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</div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Rarity%2C+J+G&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Rarity%2C+J+G&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Rarity%2C+J+G&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.04075">arXiv:2404.04075</a> <span> [<a href="https://arxiv.org/pdf/2404.04075">pdf</a>, <a href="https://arxiv.org/format/2404.04075">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> </div> </div> <p class="title is-5 mathjax"> Crosstalk-mitigated microelectronic control for optically-active spins </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Weng%2C+H">Hao-Cheng Weng</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Balram%2C+K+C">Krishna C. Balram</a>, <a href="/search/quant-ph?searchtype=author&query=Smith%2C+J+A">Joe A. Smith</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2404.04075v1-abstract-short" style="display: inline;"> To exploit the sub-nanometre dimensions of qubits for large-scale quantum information processing, corresponding control architectures require both energy and space efficiency, with the on-chip footprint of unit-cell electronics ideally micron-scale. However, the spin coherence of qubits in close packing is severely deteriorated by microwave crosstalk from neighbouring control sites. Here, we prese… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.04075v1-abstract-full').style.display = 'inline'; document.getElementById('2404.04075v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.04075v1-abstract-full" style="display: none;"> To exploit the sub-nanometre dimensions of qubits for large-scale quantum information processing, corresponding control architectures require both energy and space efficiency, with the on-chip footprint of unit-cell electronics ideally micron-scale. However, the spin coherence of qubits in close packing is severely deteriorated by microwave crosstalk from neighbouring control sites. Here, we present a crosstalk-mitigation scheme using foundry microelectronics, to address solid-state spins at sub-100 um spacing without the need for qubit-detuning. Using nitrogen-vacancy centres in nanodiamonds as qubit prototypes, we first demonstrate 10 MHz Rabi oscillation at milliwatts of microwave power. Implementing the active cancellation, we then prove that the crosstalk field from neighbouring lattice sites can be reduced to undetectable levels. We finally extend the scheme to show increased qubit control, tripling the spin coherence under crosstalk mitigation. Compatible with integrated optics, our results present a step towards scalable control across quantum platforms using silicon microelectronics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.04075v1-abstract-full').style.display = 'none'; document.getElementById('2404.04075v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.08439">arXiv:2306.08439</a> <span> [<a href="https://arxiv.org/pdf/2306.08439">pdf</a>, <a href="https://arxiv.org/format/2306.08439">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Coherent scattering from coupled two level systems </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Nutz%2C+T">Thomas Nutz</a>, <a href="/search/quant-ph?searchtype=author&query=Mister%2C+S+T">Samuel T. Mister</a>, <a href="/search/quant-ph?searchtype=author&query=Androvitsaneas%2C+P">Petros Androvitsaneas</a>, <a href="/search/quant-ph?searchtype=author&query=Young%2C+A">Andrew Young</a>, <a href="/search/quant-ph?searchtype=author&query=Harbord%2C+E">E. Harbord</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Oulton%2C+R">Ruth Oulton</a>, <a href="/search/quant-ph?searchtype=author&query=McCutcheon%2C+D+P+S">Dara P. S. McCutcheon</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.08439v1-abstract-short" style="display: inline;"> We study the resonance fluorescence properties of an optically active spin 1/2 system, elucidating the effects of a magnetic field on the coherence of the scattered light. We derive a master equation model for this system that reproduces the results of a two level system (TLS) while also being applicable to a spin system with ground state coupling. This model is then solved analytically in the wea… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.08439v1-abstract-full').style.display = 'inline'; document.getElementById('2306.08439v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.08439v1-abstract-full" style="display: none;"> We study the resonance fluorescence properties of an optically active spin 1/2 system, elucidating the effects of a magnetic field on the coherence of the scattered light. We derive a master equation model for this system that reproduces the results of a two level system (TLS) while also being applicable to a spin system with ground state coupling. This model is then solved analytically in the weak excitation regime. The inclusion of spin dynamics in our model alters the properties of the coherently scattered light at a fundamental level. For a TLS the coherence properties are known to be determined by the input laser. We show that spin scattered light inherits the coherence properties of the spin. This mapping allows us to measure spin dynamics and coherence time through direct measurement of the scattered fields. Furthermore, we show the ability to resolve sub-natural linewidth zeeman splittings. Along with representing an invaluable tool for spin spectroscopy understanding the coherence properties of the spin-scattered field will be vital for spin-photon based quantum technologies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.08439v1-abstract-full').style.display = 'none'; document.getElementById('2306.08439v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.10227">arXiv:2304.10227</a> <span> [<a href="https://arxiv.org/pdf/2304.10227">pdf</a>, <a href="https://arxiv.org/format/2304.10227">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acsphotonics.3c00713">10.1021/acsphotonics.3c00713 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Heterogeneous integration of solid state quantum systems with a foundry photonics platform </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Weng%2C+H">Hao-Cheng Weng</a>, <a href="/search/quant-ph?searchtype=author&query=Monroy-Ruz%2C+J">Jorge Monroy-Ruz</a>, <a href="/search/quant-ph?searchtype=author&query=Matthews%2C+J+C+F">Jonathan C. F. Matthews</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Balram%2C+K+C">Krishna C. Balram</a>, <a href="/search/quant-ph?searchtype=author&query=Smith%2C+J+A">Joe A. Smith</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2304.10227v1-abstract-short" style="display: inline;"> Diamond colour centres are promising optically-addressable solid state spins that can be matter-qubits, mediate deterministic interaction between photons and act as single photon emitters. Useful quantum computers will comprise millions of logical qubits. To become useful in constructing quantum computers, spin-photon interfaces must therefore become scalable and be compatible with mass-manufactur… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.10227v1-abstract-full').style.display = 'inline'; document.getElementById('2304.10227v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.10227v1-abstract-full" style="display: none;"> Diamond colour centres are promising optically-addressable solid state spins that can be matter-qubits, mediate deterministic interaction between photons and act as single photon emitters. Useful quantum computers will comprise millions of logical qubits. To become useful in constructing quantum computers, spin-photon interfaces must therefore become scalable and be compatible with mass-manufacturable photonics and electronics. Here we demonstrate heterogeneous integration of NV centres in nanodiamond with low-fluorescence silicon nitride photonics from a standard 180 nm CMOS foundry process. Nanodiamonds are positioned over pre-defined sites in a regular array on a waveguide, in a single post-processing step. Using an array of optical fibres, we excite NV centres selectively from an array of six integrated nanodiamond sites, and collect the photoluminescence (PL) in each case into waveguide circuitry on-chip. We verify single photon emission by an on-chip Hanbury Brown and Twiss cross-correlation measurement, which is a key characterisation experiment otherwise typically performed routinely with discrete optics. Our work opens up a simple and effective route to simultaneously address large arrays of individual optically-active spins at scale, without requiring discrete bulk optical setups. This is enabled by the heterogeneous integration of NV centre nanodiamonds with CMOS photonics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.10227v1-abstract-full').style.display = 'none'; document.getElementById('2304.10227v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures, and supplementary material</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ACS Photonics 2023, 10, 9, 3302-3309 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.17258">arXiv:2303.17258</a> <span> [<a href="https://arxiv.org/pdf/2303.17258">pdf</a>, <a href="https://arxiv.org/format/2303.17258">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Integrate and scale: A source of spectrally separable photon pairs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Burridge%2C+B+M">Ben M. Burridge</a>, <a href="/search/quant-ph?searchtype=author&query=Faruque%2C+I+I">Imad I. Faruque</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Barreto%2C+J">Jorge Barreto</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.17258v1-abstract-short" style="display: inline;"> Integrated photonics is a powerful contender in the race for a fault-tolerant quantum computer, claiming to be a platform capable of scaling to the necessary number of qubits. This necessitates the use of high-quality quantum states, which we create here using an all-around high-performing photon source on an integrated photonics platform. We use a photonic molecule architecture and broadband dire… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.17258v1-abstract-full').style.display = 'inline'; document.getElementById('2303.17258v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.17258v1-abstract-full" style="display: none;"> Integrated photonics is a powerful contender in the race for a fault-tolerant quantum computer, claiming to be a platform capable of scaling to the necessary number of qubits. This necessitates the use of high-quality quantum states, which we create here using an all-around high-performing photon source on an integrated photonics platform. We use a photonic molecule architecture and broadband directional couplers to protect against fabrication tolerances and ensure reliable operation. As a result, we simultaneously measure a spectral purity of $99.1 \pm 0.1$ %, a pair generation rate of $4.4 \pm 0.1$ MHz mW$^{-2}$, and an intrinsic source heralding efficiency of $94.0 \pm 2.9$ %. We also see a maximum coincidence-to-accidental ratio of $1644 \pm 263$. We claim over an order of magnitude improvement in the trivariate trade-off between source heralding efficiency, purity and brightness. Future implementations of the source could achieve in excess of $99$ % purity and heralding efficiency using state-of-the-art propagation losses. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.17258v1-abstract-full').style.display = 'none'; document.getElementById('2303.17258v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures (main text), 11 pages 14 figures (supplementary text), pre-print</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.12521">arXiv:2212.12521</a> <span> [<a href="https://arxiv.org/pdf/2212.12521">pdf</a>, <a href="https://arxiv.org/format/2212.12521">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/2058-9565/acf47b">10.1088/2058-9565/acf47b <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum-Referenced Spontaneous Emission Tomography </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Faruque%2C+I+I">I. I. Faruque</a>, <a href="/search/quant-ph?searchtype=author&query=Burridge%2C+B+M">B. M. Burridge</a>, <a href="/search/quant-ph?searchtype=author&query=Banic%2C+M">M. Banic</a>, <a href="/search/quant-ph?searchtype=author&query=Borghi%2C+M">M. Borghi</a>, <a href="/search/quant-ph?searchtype=author&query=Sipe%2C+J+E">J. E. Sipe</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Barreto%2C+J">J. Barreto</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2212.12521v3-abstract-short" style="display: inline;"> We present a method of tomography that measures the joint spectral phase (JSP) of spontaneously emitted photon pairs originating from a largely uncharacterized ``target" source. We use quantum interference between our target source and a reference source to extract the JSP with four spectrally resolved measurements, in a process that we call quantum-referenced spontaneous emission tomography (Q-Sp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.12521v3-abstract-full').style.display = 'inline'; document.getElementById('2212.12521v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.12521v3-abstract-full" style="display: none;"> We present a method of tomography that measures the joint spectral phase (JSP) of spontaneously emitted photon pairs originating from a largely uncharacterized ``target" source. We use quantum interference between our target source and a reference source to extract the JSP with four spectrally resolved measurements, in a process that we call quantum-referenced spontaneous emission tomography (Q-SpET). We have demonstrated this method on a photonic integrated circuit for a target micro-ring resonator photon-pair source. Our results show that spontaneously emitted photon pairs from a micro-ring resonator are distinctively different from that of stimulated emission, and thus cannot in general be fully characterized using classical stimulated emission tomography without detailed knowledge of the source. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.12521v3-abstract-full').style.display = 'none'; document.getElementById('2212.12521v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Quantum Sci. Technol. 8 045024 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.09051">arXiv:2211.09051</a> <span> [<a href="https://arxiv.org/pdf/2211.09051">pdf</a>, <a href="https://arxiv.org/format/2211.09051">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1117/12.2645095">10.1117/12.2645095 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Entanglement distribution quantum networking within deployed telecommunications fibre-optic infrastructure </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Clark%2C+M+J">Marcus J Clark</a>, <a href="/search/quant-ph?searchtype=author&query=Alia%2C+O">Obada Alia</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+R">Rui Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Bahrani%2C+S">Sima Bahrani</a>, <a href="/search/quant-ph?searchtype=author&query=Peranic%2C+M">Matej Peranic</a>, <a href="/search/quant-ph?searchtype=author&query=Aktas%2C+D">Djeylan Aktas</a>, <a href="/search/quant-ph?searchtype=author&query=Kanellos%2C+G+T">George T Kanellos</a>, <a href="/search/quant-ph?searchtype=author&query=Loncaric%2C+M">Martin Loncaric</a>, <a href="/search/quant-ph?searchtype=author&query=Samec%2C+Z">Zeljko Samec</a>, <a href="/search/quant-ph?searchtype=author&query=Radman%2C+A">Anton Radman</a>, <a href="/search/quant-ph?searchtype=author&query=Stipcevic%2C+M">Mario Stipcevic</a>, <a href="/search/quant-ph?searchtype=author&query=Nejabati%2C+R">Reza Nejabati</a>, <a href="/search/quant-ph?searchtype=author&query=Simeonidou%2C+D">Dimitra Simeonidou</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+S+K">Siddarth K Joshi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2211.09051v4-abstract-short" style="display: inline;"> Quantum networks have been shown to connect users with full-mesh topologies without trusted nodes. We present advancements on our scalable polarisation entanglement-based quantum network testbed, which has the ability to perform protocols beyond simple quantum key distribution. Our approach utilises wavelength multiplexing, which is ideal for quantum networks across local metropolitan areas due to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.09051v4-abstract-full').style.display = 'inline'; document.getElementById('2211.09051v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.09051v4-abstract-full" style="display: none;"> Quantum networks have been shown to connect users with full-mesh topologies without trusted nodes. We present advancements on our scalable polarisation entanglement-based quantum network testbed, which has the ability to perform protocols beyond simple quantum key distribution. Our approach utilises wavelength multiplexing, which is ideal for quantum networks across local metropolitan areas due to the ease of connecting additional users to the network without increasing the resource requirements per user. We show a 10 user fully connected quantum network with metropolitan scale deployed fibre links, demonstrating polarisation stability and the ability to generate secret keys over a period of 10.8 days with a network wide average-effective secret key rate of 3.38 bps. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.09051v4-abstract-full').style.display = 'none'; document.getElementById('2211.09051v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures, 2 tables, SPIE Photonex 2022 conference proceedings</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Proc. SPIE 12335, Quantum Technology: Driving Commercialisation of an Enabling Science III, 123350E (11 January 2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.11285">arXiv:2210.11285</a> <span> [<a href="https://arxiv.org/pdf/2210.11285">pdf</a>, <a href="https://arxiv.org/format/2210.11285">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Responsive Operations for Key Services (ROKS): A Modular, Low SWaP Quantum Communications Payload </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Colquhoun%2C+C+D">Craig D. Colquhoun</a>, <a href="/search/quant-ph?searchtype=author&query=Jeffrey%2C+H">Hazel Jeffrey</a>, <a href="/search/quant-ph?searchtype=author&query=Greenland%2C+S">Steve Greenland</a>, <a href="/search/quant-ph?searchtype=author&query=Mohapatra%2C+S">Sonali Mohapatra</a>, <a href="/search/quant-ph?searchtype=author&query=Aitken%2C+C">Colin Aitken</a>, <a href="/search/quant-ph?searchtype=author&query=Cebecauer%2C+M">Mikulas Cebecauer</a>, <a href="/search/quant-ph?searchtype=author&query=Crawshaw%2C+C">Charlotte Crawshaw</a>, <a href="/search/quant-ph?searchtype=author&query=Jeffrey%2C+K">Kenny Jeffrey</a>, <a href="/search/quant-ph?searchtype=author&query=Jeffreys%2C+T">Toby Jeffreys</a>, <a href="/search/quant-ph?searchtype=author&query=Karagiannakis%2C+P">Philippos Karagiannakis</a>, <a href="/search/quant-ph?searchtype=author&query=McTaggart%2C+A">Ahren McTaggart</a>, <a href="/search/quant-ph?searchtype=author&query=Stark%2C+C">Caitlin Stark</a>, <a href="/search/quant-ph?searchtype=author&query=Wood%2C+J">Jack Wood</a>, <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+S+K">Siddarth K. Joshi</a>, <a href="/search/quant-ph?searchtype=author&query=Sagar%2C+J">Jaya Sagar</a>, <a href="/search/quant-ph?searchtype=author&query=Hastings%2C+E">Elliott Hastings</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">Peide Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Stefko%2C+M">Milan Stefko</a>, <a href="/search/quant-ph?searchtype=author&query=Lowndes%2C+D">David Lowndes</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Sidhu%2C+J+S">Jasminder S. Sidhu</a>, <a href="/search/quant-ph?searchtype=author&query=Brougham%2C+T">Thomas Brougham</a>, <a href="/search/quant-ph?searchtype=author&query=McArthur%2C+D">Duncan McArthur</a>, <a href="/search/quant-ph?searchtype=author&query=Pousa%2C+R+G">Robert G. Pousa</a>, <a href="/search/quant-ph?searchtype=author&query=Oi%2C+D+K+L">Daniel K. L. Oi</a> , et al. (3 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2210.11285v1-abstract-short" style="display: inline;"> Quantum key distribution (QKD) is a theoretically proven future-proof secure encryption method that inherits its security from fundamental physical principles. Craft Prospect, working with a number of UK organisations, has been focused on miniaturising the technologies that enable QKD so that they may be used in smaller platforms including nanosatellites. The significant reduction of size, and the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.11285v1-abstract-full').style.display = 'inline'; document.getElementById('2210.11285v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.11285v1-abstract-full" style="display: none;"> Quantum key distribution (QKD) is a theoretically proven future-proof secure encryption method that inherits its security from fundamental physical principles. Craft Prospect, working with a number of UK organisations, has been focused on miniaturising the technologies that enable QKD so that they may be used in smaller platforms including nanosatellites. The significant reduction of size, and therefore the cost of launching quantum communication technologies either on a dedicated platform or hosted as part of a larger optical communications will improve potential access to quantum encryption on a relatively quick timescale. The ROKS mission seeks to be among the first to send a QKD payload on a CubeSat into low Earth orbit, demonstrating the capabilities of newly developed modular quantum technologies. The ROKS payload comprises a quantum source module that supplies photons randomly in any of four linear polarisation states fed from a quantum random number generator; an acquisition, pointing, and tracking system to fine-tune alignment of the quantum source beam with an optical ground station; an imager that will detect cloud cover autonomously; and an onboard computer that controls and monitors the other modules, which manages the payload and assures the overall performance and security of the system. Each of these modules have been developed with low SWaP for CubeSats, but with interoperability in mind for other satellite form factors. We present each of the listed components, together with the initial test results from our test bench and the performance of our protoflight models prior to initial integration with the 6U CubeSat platform systems. The completed ROKS payload will be ready for flight at the end of 2022, with various modular components already being baselined for flight and integrated into third party communication missions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.11285v1-abstract-full').style.display = 'none'; document.getElementById('2210.11285v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages with 25 figures. Presented at Small Satellite Conference: https://digitalcommons.usu.edu/smallsat/2022/all2022/163/. Any comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.15289">arXiv:2209.15289</a> <span> [<a href="https://arxiv.org/pdf/2209.15289">pdf</a>, <a href="https://arxiv.org/format/2209.15289">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/OPTCON.524280">10.1364/OPTCON.524280 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Methane sensing in the mid-IR using short wave IR photon counting detectors via non-linear interferometry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cardoso%2C+A+C">Arthur C. Cardoso</a>, <a href="/search/quant-ph?searchtype=author&query=Dong%2C+J">Jinghan Dong</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+H">Haichen Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+S+K">Siddarth K. Joshi</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2209.15289v2-abstract-short" style="display: inline;"> We demonstrate a novel MIR methane sensor shifting measurement wavelength to SWIR (1.55$渭$m) by using non-linear interferometry. The technique exploits the interference effects seen in three-wave mixing when pump, signal, and idler modes make a double pass through a nonlinear crystal. The method allows sensing at wavelengths where detectors are poor ($>$3$渭$m) and detection at wavelengths where ph… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.15289v2-abstract-full').style.display = 'inline'; document.getElementById('2209.15289v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.15289v2-abstract-full" style="display: none;"> We demonstrate a novel MIR methane sensor shifting measurement wavelength to SWIR (1.55$渭$m) by using non-linear interferometry. The technique exploits the interference effects seen in three-wave mixing when pump, signal, and idler modes make a double pass through a nonlinear crystal. The method allows sensing at wavelengths where detectors are poor ($>$3$渭$m) and detection at wavelengths where photon counting sensitivity can be achieved. In a first experimental demonstration, we measured a small methane concentration inside a gas cell with high precision. This interferometer can be built in a compact design for field operations and potentially enable the detection of low concentrations of methane at up to 100m range. Signal-to-noise ratio calculations show that the method can outperform existing short wavelength ($\sim$1.65$渭$m) integrated path differential absorption direct sensing at high ($>$$10^{-4}$) non-linear gain. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.15289v2-abstract-full').style.display = 'none'; document.getElementById('2209.15289v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Title change, new data, significant revision, 10 pages 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Optics Continuum, 3(5), 823-832 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.14317">arXiv:2209.14317</a> <span> [<a href="https://arxiv.org/pdf/2209.14317">pdf</a>, <a href="https://arxiv.org/format/2209.14317">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantifying Hidden Nonlinear Noise in Integrated Photonics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Burridge%2C+B+M">Ben M. Burridge</a>, <a href="/search/quant-ph?searchtype=author&query=Faruque%2C+I+I">Imad I. Faruque</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Barreto%2C+J">Jorge Barreto</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2209.14317v1-abstract-short" style="display: inline;"> We present experimental and simulated results to quantify the impact of nonlinear noise in integrated photonic devices relying on spontaneous four-wave mixing. Our results highlight the need for design rule adaptations to mitigate the otherwise intrinsic reduction in quantum state purity. The best strategy in devices with multiple parallel photon sources is to strictly limit photon generation outs… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.14317v1-abstract-full').style.display = 'inline'; document.getElementById('2209.14317v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.14317v1-abstract-full" style="display: none;"> We present experimental and simulated results to quantify the impact of nonlinear noise in integrated photonic devices relying on spontaneous four-wave mixing. Our results highlight the need for design rule adaptations to mitigate the otherwise intrinsic reduction in quantum state purity. The best strategy in devices with multiple parallel photon sources is to strictly limit photon generation outside of the sources. Otherwise, our results suggest that purity can decrease below 40%. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.14317v1-abstract-full').style.display = 'none'; document.getElementById('2209.14317v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 5 figures, pre-print</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.07270">arXiv:2207.07270</a> <span> [<a href="https://arxiv.org/pdf/2207.07270">pdf</a>, <a href="https://arxiv.org/format/2207.07270">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevA.108.012215">10.1103/PhysRevA.108.012215 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Controlling and measuring a superposition of position and momentum </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ono%2C+T">Takafumi Ono</a>, <a href="/search/quant-ph?searchtype=author&query=Samantarray%2C+N">Nigam Samantarray</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.07270v1-abstract-short" style="display: inline;"> The dynamics of a particle propagating in free space is described by its position and momentum, where quantum mechanics prohibits the simultaneous identification of two non-commutative physical quantities. Recently, a lower bound on the probability of finding a particle after propagating for a given time has been derived for well-defined initial constraints on position and momentum under the assum… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.07270v1-abstract-full').style.display = 'inline'; document.getElementById('2207.07270v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.07270v1-abstract-full" style="display: none;"> The dynamics of a particle propagating in free space is described by its position and momentum, where quantum mechanics prohibits the simultaneous identification of two non-commutative physical quantities. Recently, a lower bound on the probability of finding a particle after propagating for a given time has been derived for well-defined initial constraints on position and momentum under the assumption that particles travel in straight lines. Here, we investigate this lower limit experimentally with photons. We prepared a superposition of position and momentum states by using slits, lenses and an interferometer, and observed a quantum interference between position and momentum. The lower bound was then evaluated using the initial state and the result was 5.9\% below this classical bound. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.07270v1-abstract-full').style.display = 'none'; document.getElementById('2207.07270v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.05596">arXiv:2207.05596</a> <span> [<a href="https://arxiv.org/pdf/2207.05596">pdf</a>, <a href="https://arxiv.org/format/2207.05596">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum modulation of a coherent state wavepacket with a single electron spin </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Androvitsaneas%2C+P">P. Androvitsaneas</a>, <a href="/search/quant-ph?searchtype=author&query=Young%2C+A+B">A. B. Young</a>, <a href="/search/quant-ph?searchtype=author&query=Nutz%2C+T">T. Nutz</a>, <a href="/search/quant-ph?searchtype=author&query=Lennon%2C+J+M">J. M. Lennon</a>, <a href="/search/quant-ph?searchtype=author&query=Mister%2C+S">S. Mister</a>, <a href="/search/quant-ph?searchtype=author&query=Schneider%2C+C">C. Schneider</a>, <a href="/search/quant-ph?searchtype=author&query=Kamp%2C+M">M. Kamp</a>, <a href="/search/quant-ph?searchtype=author&query=H%C3%B6fling%2C+S">S. H枚fling</a>, <a href="/search/quant-ph?searchtype=author&query=McCutcheon%2C+D+P+S">D. P. S. McCutcheon</a>, <a href="/search/quant-ph?searchtype=author&query=Harbord%2C+E">E. Harbord</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Oulton%2C+R">R. Oulton</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.05596v1-abstract-short" style="display: inline;"> The interaction of quantum objects lies at the heart of fundamental quantum physics and is key to a wide range of quantum information technologies. Photon-quantum-emitter interactions are among the most widely studied. Two-qubit interactions are generally simplified into two quantum objects in static well-defined states . In this work we explore a fundamentally new dynamic type of spin-photon inte… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.05596v1-abstract-full').style.display = 'inline'; document.getElementById('2207.05596v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.05596v1-abstract-full" style="display: none;"> The interaction of quantum objects lies at the heart of fundamental quantum physics and is key to a wide range of quantum information technologies. Photon-quantum-emitter interactions are among the most widely studied. Two-qubit interactions are generally simplified into two quantum objects in static well-defined states . In this work we explore a fundamentally new dynamic type of spin-photon interaction. We demonstrate modulation of a coherent narrowband wavepacket with another truly quantum object, a quantum dot with ground state spin degree of freedom. What results is a quantum modulation of the wavepacket phase (either 0 or 蟺 but no values in between), a new quantum state of light that cannot be described classically. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.05596v1-abstract-full').style.display = 'none'; document.getElementById('2207.05596v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Supplementary Information available on request</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.04641">arXiv:2202.04641</a> <span> [<a href="https://arxiv.org/pdf/2202.04641">pdf</a>, <a href="https://arxiv.org/format/2202.04641">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cryptography and Security">cs.CR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1367-2630/ac8e25">10.1088/1367-2630/ac8e25 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Unconditionally secure digital signatures implemented in an 8-user quantum network </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Pelet%2C+Y">Yoann Pelet</a>, <a href="/search/quant-ph?searchtype=author&query=Puthoor%2C+I+V">Ittoop Vergheese Puthoor</a>, <a href="/search/quant-ph?searchtype=author&query=Venkatachalam%2C+N">Natarajan Venkatachalam</a>, <a href="/search/quant-ph?searchtype=author&query=Wengerowsky%2C+S">S枚ren Wengerowsky</a>, <a href="/search/quant-ph?searchtype=author&query=Lon%C4%8Dari%C4%87%2C+M">Martin Lon膷ari膰</a>, <a href="/search/quant-ph?searchtype=author&query=Neumann%2C+S+P">Sebastian Philipp Neumann</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bo Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Samec%2C+%C5%BD">沤eljko Samec</a>, <a href="/search/quant-ph?searchtype=author&query=Stip%C4%8Devi%C4%87%2C+M">Mario Stip膷evi膰</a>, <a href="/search/quant-ph?searchtype=author&query=Ursin%2C+R">Rupert Ursin</a>, <a href="/search/quant-ph?searchtype=author&query=Andersson%2C+E">Erika Andersson</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Aktas%2C+D">Djeylan Aktas</a>, <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+S+K">Siddarth Koduru Joshi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2202.04641v2-abstract-short" style="display: inline;"> The ability to know and verifiably demonstrate the origins of messages can often be as important as encrypting the message itself. Here we present an experimental demonstration of an unconditionally secure digital signature (USS) protocol implemented for the first time, to the best of our knowledge, on a fully connected quantum network without trusted nodes. Our USS protocol is secure against forg… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.04641v2-abstract-full').style.display = 'inline'; document.getElementById('2202.04641v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.04641v2-abstract-full" style="display: none;"> The ability to know and verifiably demonstrate the origins of messages can often be as important as encrypting the message itself. Here we present an experimental demonstration of an unconditionally secure digital signature (USS) protocol implemented for the first time, to the best of our knowledge, on a fully connected quantum network without trusted nodes. Our USS protocol is secure against forging, repudiation and messages are transferrable. We show the feasibility of unconditionally secure signatures using only bi-partite entangled states distributed throughout the network and experimentally evaluate the performance of the protocol in real world scenarios with varying message lengths. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.04641v2-abstract-full').style.display = 'none'; document.getElementById('2202.04641v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Preprint, 9 pages, 7 figures, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.01124">arXiv:2110.01124</a> <span> [<a href="https://arxiv.org/pdf/2110.01124">pdf</a>, <a href="https://arxiv.org/format/2110.01124">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Un-symmetric photon subtraction: a method for generating high photon number states and their relevance to loss estimation at ultimate quantum limit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Samantaray%2C+N">N. Samantaray</a>, <a href="/search/quant-ph?searchtype=author&query=Matthews%2C+J+C+F">J. C. F. Matthews</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2110.01124v1-abstract-short" style="display: inline;"> We have studied theoretical un-symmetric multi-photon subtracted twin beam state and demonstrated a method for generating states that resembles to high photon number states with the increase in the number of subtracted photons through Wigner distribution function, which can be reconstructed experimentally by Homodyne measurement. A crucial point is high non-classicality is obtained by photon subtr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.01124v1-abstract-full').style.display = 'inline'; document.getElementById('2110.01124v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.01124v1-abstract-full" style="display: none;"> We have studied theoretical un-symmetric multi-photon subtracted twin beam state and demonstrated a method for generating states that resembles to high photon number states with the increase in the number of subtracted photons through Wigner distribution function, which can be reconstructed experimentally by Homodyne measurement. A crucial point is high non-classicality is obtained by photon subtraction when mean photons per mode of twin beam state is low. We have calculated photon statistics from the phase space distribution function and found sub-poissonian behaviour in the same low mean photons regime. Furthermore, we have tested the usefulness of such states for realistic absorption measurement including detection losses by computing quantum Fisher-Information from measured Wigner function after interaction the sample. We have compared the performance of these states with respect to coherent and demonstrated how the quantum advantage is related to non-classical enhancement. We presented results up to three photon subtraction which show remarkable quantum advantage over both initial thermal and coherent state reaching the ultimate quantum limit in the loss estimation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.01124v1-abstract-full').style.display = 'none'; document.getElementById('2110.01124v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 page, 7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.12225">arXiv:2101.12225</a> <span> [<a href="https://arxiv.org/pdf/2101.12225">pdf</a>, <a href="https://arxiv.org/format/2101.12225">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PRXQuantum.3.020311">10.1103/PRXQuantum.3.020311 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Scalable authentication and optimal flooding in a quantum network </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Solomons%2C+N+R">Naomi R. Solomons</a>, <a href="/search/quant-ph?searchtype=author&query=Fletcher%2C+A+I">Alasdair I. Fletcher</a>, <a href="/search/quant-ph?searchtype=author&query=Aktas%2C+D">Djeylan Aktas</a>, <a href="/search/quant-ph?searchtype=author&query=Venkatachalam%2C+N">Natarajan Venkatachalam</a>, <a href="/search/quant-ph?searchtype=author&query=Wengerowsky%2C+S">S枚ren Wengerowsky</a>, <a href="/search/quant-ph?searchtype=author&query=Lon%C4%8Dari%C4%87%2C+M">Martin Lon膷ari膰</a>, <a href="/search/quant-ph?searchtype=author&query=Neumann%2C+S+P">Sebastian P. Neumann</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bo Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Samec%2C+%C5%BD">沤eljko Samec</a>, <a href="/search/quant-ph?searchtype=author&query=Stip%C4%8Devi%C4%87%2C+M">Mario Stip膷evi膰</a>, <a href="/search/quant-ph?searchtype=author&query=Ursin%2C+R">Rupert Ursin</a>, <a href="/search/quant-ph?searchtype=author&query=Pirandola%2C+S">Stefano Pirandola</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+S+K">Siddarth Koduru Joshi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2101.12225v2-abstract-short" style="display: inline;"> The global interest in quantum networks stems from the security guaranteed by the laws of physics. Deploying quantum networks means facing the challenges of scaling up the physical hardware and, more importantly, of scaling up all other network layers and optimally utilising network resources. Here we consider two related protocols, their experimental demonstrations on an 8-user quantum network te… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.12225v2-abstract-full').style.display = 'inline'; document.getElementById('2101.12225v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.12225v2-abstract-full" style="display: none;"> The global interest in quantum networks stems from the security guaranteed by the laws of physics. Deploying quantum networks means facing the challenges of scaling up the physical hardware and, more importantly, of scaling up all other network layers and optimally utilising network resources. Here we consider two related protocols, their experimental demonstrations on an 8-user quantum network test-bed, and discuss their usefulness with the aid of example use cases. First, an authentication transfer protocol to manage a fundamental limitation of quantum communication -- the need for a pre-shared key between every pair of users linked together on the quantum network. By temporarily trusting some intermediary nodes for a short period of time (<35 min in our network), we can generate and distribute these initial authentication keys with a very high level of security. Second, when end users quantify their trust in intermediary nodes, our flooding protocol can be used to improve both end-to-end communication speeds and increase security against malicious nodes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.12225v2-abstract-full').style.display = 'none'; document.getElementById('2101.12225v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">New version includes changes suggested by referees, and a modification to an incorrect calculation. Fig. 6 has been updated correspondingly. With thanks to Rui Wang for spotting the mistake, and the referees for detailed feedback</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PRX Quantum 3, 020311 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.09480">arXiv:2011.09480</a> <span> [<a href="https://arxiv.org/pdf/2011.09480">pdf</a>, <a href="https://arxiv.org/format/2011.09480">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cryptography and Security">cs.CR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Emerging Technologies">cs.ET</span> </div> </div> <p class="title is-5 mathjax"> Experimental implementation of secure anonymous protocols on an eight-user quantum network </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Z">Zixin Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+S+K">Siddarth Koduru Joshi</a>, <a href="/search/quant-ph?searchtype=author&query=Aktas%2C+D">Djeylan Aktas</a>, <a href="/search/quant-ph?searchtype=author&query=Lupo%2C+C">Cosmo Lupo</a>, <a href="/search/quant-ph?searchtype=author&query=Quintavalle%2C+A+O">Armanda O. Quintavalle</a>, <a href="/search/quant-ph?searchtype=author&query=Venkatachalam%2C+N">Natarajan Venkatachalam</a>, <a href="/search/quant-ph?searchtype=author&query=Wengerowsky%2C+S">S枚ren Wengerowsky</a>, <a href="/search/quant-ph?searchtype=author&query=Lon%C4%8Dari%C4%87%2C+M">Martin Lon膷ari膰</a>, <a href="/search/quant-ph?searchtype=author&query=Neumann%2C+S+P">Sebastian Philipp Neumann</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bo Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Samec%2C+%C5%BD">沤eljko Samec</a>, <a href="/search/quant-ph?searchtype=author&query=Kling%2C+L">Laurent Kling</a>, <a href="/search/quant-ph?searchtype=author&query=Stip%C4%8Devi%C4%87%2C+M">Mario Stip膷evi膰</a>, <a href="/search/quant-ph?searchtype=author&query=Ursin%2C+R">Rupert Ursin</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2011.09480v1-abstract-short" style="display: inline;"> Anonymity in networked communication is vital for many privacy-preserving tasks. Secure key distribution alone is insufficient for high-security communications, often knowing who transmits a message to whom and when must also be kept hidden from an adversary. Here we experimentally demonstrate 5 information-theoretically secure anonymity protocols on an 8 user city-wide quantum network using polar… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.09480v1-abstract-full').style.display = 'inline'; document.getElementById('2011.09480v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.09480v1-abstract-full" style="display: none;"> Anonymity in networked communication is vital for many privacy-preserving tasks. Secure key distribution alone is insufficient for high-security communications, often knowing who transmits a message to whom and when must also be kept hidden from an adversary. Here we experimentally demonstrate 5 information-theoretically secure anonymity protocols on an 8 user city-wide quantum network using polarisation-entangled photon pairs. At the heart of these protocols is anonymous broadcasting, which is a cryptographic primitive that allows one user to reveal one bit of information while keeping her identity anonymous. For a network of $n$ users, the protocols retain anonymity for the sender, given less than $n-2$ users are dishonest. This is one of the earliest implementations of genuine multi-user cryptographic protocols beyond standard QKD. Our anonymous protocols enhance the functionality of any fully-connected Quantum Key Distribution network without trusted nodes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.09480v1-abstract-full').style.display = 'none'; document.getElementById('2011.09480v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 4 figures, 1 table, experimental work. ZH and SKJ contributed equally to this work and are joint first authors</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.11586">arXiv:2009.11586</a> <span> [<a href="https://arxiv.org/pdf/2009.11586">pdf</a>, <a href="https://arxiv.org/format/2009.11586">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevA.104.063718">10.1103/PhysRevA.104.063718 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Poissonian twin beam states and the effect of symmetrical photon subtraction in loss estimations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Samantaray%2C+N">N. Samantaray</a>, <a href="/search/quant-ph?searchtype=author&query=Matthews%2C+J+C+F">J. C. F. Matthews</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2009.11586v1-abstract-short" style="display: inline;"> We have devised an experimentally realizable model generating twin beam states whose individual beam photon statistics are varied from thermal to Poissonian keeping the non-classical mode correlation intact. We have studied the usefulness of these states for loss measurement by considering three different estimators, comparing with the correlated thermal twin beam states generated from spontaneous… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.11586v1-abstract-full').style.display = 'inline'; document.getElementById('2009.11586v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.11586v1-abstract-full" style="display: none;"> We have devised an experimentally realizable model generating twin beam states whose individual beam photon statistics are varied from thermal to Poissonian keeping the non-classical mode correlation intact. We have studied the usefulness of these states for loss measurement by considering three different estimators, comparing with the correlated thermal twin beam states generated from spontaneous parametric down conversion or four-wave mixing. We then incorporated the photon subtraction operation into the model and demonstrate their advantage in loss estimations with respect to un-subtracted states at both fixed squeezing and per photon exposure of the absorbing sample. For instance, at fixed squeezing, for two photon subtraction, up to three times advantage is found. In the latter case, albeit the advantage due to photon subtraction mostly subsides in standard regime, an unexpected result is that in some operating regimes the photon subtraction scheme can also give up to 20% advantage over the correlated Poisson beam result. We have also made a comparative study of these estimators for finding the best measurement for loss estimations. We present results for all the values of the model parameters changing the statistics of twin beam states from thermal to Poissonian. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.11586v1-abstract-full').style.display = 'none'; document.getElementById('2009.11586v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 12 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.08339">arXiv:2009.08339</a> <span> [<a href="https://arxiv.org/pdf/2009.08339">pdf</a>, <a href="https://arxiv.org/format/2009.08339">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-021-01333-w">10.1038/s41567-021-01333-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Error protected qubits in a silicon photonic chip </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Vigliar%2C+C">Caterina Vigliar</a>, <a href="/search/quant-ph?searchtype=author&query=Paesani%2C+S">Stefano Paesani</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+Y">Yunhong Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Adcock%2C+J+C">Jeremy C. Adcock</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jianwei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Morley-Short%2C+S">Sam Morley-Short</a>, <a href="/search/quant-ph?searchtype=author&query=Bacco%2C+D">Davide Bacco</a>, <a href="/search/quant-ph?searchtype=author&query=Oxenl%C3%B8we%2C+L+K">Leif K. Oxenl酶we</a>, <a href="/search/quant-ph?searchtype=author&query=Thompson%2C+M+G">Mark G. Thompson</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Laing%2C+A">Anthony Laing</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2009.08339v1-abstract-short" style="display: inline;"> General purpose quantum computers can, in principle, entangle a number of noisy physical qubits to realise composite qubits protected against errors. Architectures for measurement-based quantum computing intrinsically support error-protected qubits and are the most viable approach for constructing an all-photonic quantum computer. Here we propose and demonstrate an integrated silicon photonic arch… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.08339v1-abstract-full').style.display = 'inline'; document.getElementById('2009.08339v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.08339v1-abstract-full" style="display: none;"> General purpose quantum computers can, in principle, entangle a number of noisy physical qubits to realise composite qubits protected against errors. Architectures for measurement-based quantum computing intrinsically support error-protected qubits and are the most viable approach for constructing an all-photonic quantum computer. Here we propose and demonstrate an integrated silicon photonic architecture that both entangles multiple photons, and encodes multiple physical qubits on individual photons, to produce error-protected qubits. We realise reconfigurable graph states to compare several schemes with and without error-correction encodings and implement a range of quantum information processing tasks. We observe a success rate increase from 62.5% to 95.8% when running a phase estimation algorithm without and with error protection, respectively. Finally, we realise hypergraph states, which are a generalised class of resource states that offer protection against correlated errors. Our results show how quantum error-correction encodings can be implemented with resource-efficient photonic architectures to improve the performance of quantum algorithms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.08339v1-abstract-full').style.display = 'none'; document.getElementById('2009.08339v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2005.13478">arXiv:2005.13478</a> <span> [<a href="https://arxiv.org/pdf/2005.13478">pdf</a>, <a href="https://arxiv.org/format/2005.13478">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevApplied.15.034029">10.1103/PhysRevApplied.15.034029 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The NV centre coupled to an ultra-small mode volume cavity: a high efficiency source of indistinguishable photons at 200 K </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Smith%2C+J+A">Joe A. Smith</a>, <a href="/search/quant-ph?searchtype=author&query=Clear%2C+C">Chloe Clear</a>, <a href="/search/quant-ph?searchtype=author&query=Balram%2C+K+C">Krishna C. Balram</a>, <a href="/search/quant-ph?searchtype=author&query=McCutcheon%2C+D+P+S">Dara P. S. McCutcheon</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2005.13478v2-abstract-short" style="display: inline;"> Solid state atom-like systems have great promise for linear optic quantum computing and quantum communication but are burdened by phonon sidebands and broadening due to surface charges. Nevertheless, coupling to a small mode volume cavity would allow high rates of extraction from even highly dephased emitters. We consider the nitrogen vacancy centre in diamond, a system understood to have a poor q… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.13478v2-abstract-full').style.display = 'inline'; document.getElementById('2005.13478v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2005.13478v2-abstract-full" style="display: none;"> Solid state atom-like systems have great promise for linear optic quantum computing and quantum communication but are burdened by phonon sidebands and broadening due to surface charges. Nevertheless, coupling to a small mode volume cavity would allow high rates of extraction from even highly dephased emitters. We consider the nitrogen vacancy centre in diamond, a system understood to have a poor quantum optics interface with highly distinguishable photons, and design a silicon nitride cavity that allows 99 % efficient extraction of photons at 200 K with an indistinguishability of > 50%, improvable by external filtering. We analyse our design using FDTD simulations, and treat optical emission using a cavity QED master equation valid at and beyond strong coupling and which includes both ZPL broadening and sideband emission. The simulated design is compact (< 10 um), and owing to its planar geometry, can be fabricated using standard silicon processes. Our work therefore points towards scalable fabrication of non-cryogenic atom-like efficient sources of indistinguishable photons. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.13478v2-abstract-full').style.display = 'none'; document.getElementById('2005.13478v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 7 figures. Results for 3-level Jahn-Teller dephasing and explicit effects of the LDOS on the sideband added</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Applied 15, 034029 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2002.06169">arXiv:2002.06169</a> <span> [<a href="https://arxiv.org/pdf/2002.06169">pdf</a>, <a href="https://arxiv.org/format/2002.06169">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Machine Learning">cs.LG</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-021-01201-7">10.1038/s41567-021-01201-7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Learning models of quantum systems from experiments </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gentile%2C+A+A">Antonio A. Gentile</a>, <a href="/search/quant-ph?searchtype=author&query=Flynn%2C+B">Brian Flynn</a>, <a href="/search/quant-ph?searchtype=author&query=Knauer%2C+S">Sebastian Knauer</a>, <a href="/search/quant-ph?searchtype=author&query=Wiebe%2C+N">Nathan Wiebe</a>, <a href="/search/quant-ph?searchtype=author&query=Paesani%2C+S">Stefano Paesani</a>, <a href="/search/quant-ph?searchtype=author&query=Granade%2C+C+E">Christopher E. Granade</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Santagati%2C+R">Raffaele Santagati</a>, <a href="/search/quant-ph?searchtype=author&query=Laing%2C+A">Anthony Laing</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2002.06169v1-abstract-short" style="display: inline;"> An isolated system of interacting quantum particles is described by a Hamiltonian operator. Hamiltonian models underpin the study and analysis of physical and chemical processes throughout science and industry, so it is crucial they are faithful to the system they represent. However, formulating and testing Hamiltonian models of quantum systems from experimental data is difficult because it is imp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.06169v1-abstract-full').style.display = 'inline'; document.getElementById('2002.06169v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2002.06169v1-abstract-full" style="display: none;"> An isolated system of interacting quantum particles is described by a Hamiltonian operator. Hamiltonian models underpin the study and analysis of physical and chemical processes throughout science and industry, so it is crucial they are faithful to the system they represent. However, formulating and testing Hamiltonian models of quantum systems from experimental data is difficult because it is impossible to directly observe which interactions the quantum system is subject to. Here, we propose and demonstrate an approach to retrieving a Hamiltonian model from experiments, using unsupervised machine learning. We test our methods experimentally on an electron spin in a nitrogen-vacancy interacting with its spin bath environment, and numerically, finding success rates up to 86%. By building agents capable of learning science, which recover meaningful representations, we can gain further insight on the physics of quantum systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.06169v1-abstract-full').style.display = 'none'; document.getElementById('2002.06169v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">27 pages, 8 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1911.07839">arXiv:1911.07839</a> <span> [<a href="https://arxiv.org/pdf/1911.07839">pdf</a>, <a href="https://arxiv.org/format/1911.07839">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-019-0727-x">10.1038/s41567-019-0727-x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Chip-to-chip quantum teleportation and multi-photon entanglement in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Llewellyn%2C+D">Daniel Llewellyn</a>, <a href="/search/quant-ph?searchtype=author&query=Ding%2C+Y">Yunhong Ding</a>, <a href="/search/quant-ph?searchtype=author&query=Faruque%2C+I+I">Imad I. Faruque</a>, <a href="/search/quant-ph?searchtype=author&query=Paesani%2C+S">Stefano Paesani</a>, <a href="/search/quant-ph?searchtype=author&query=Bacco%2C+D">Davide Bacco</a>, <a href="/search/quant-ph?searchtype=author&query=Santagati%2C+R">Raffaele Santagati</a>, <a href="/search/quant-ph?searchtype=author&query=Qian%2C+Y">Yan-Jun Qian</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+Y">Yan Li</a>, <a href="/search/quant-ph?searchtype=author&query=Xiao%2C+Y">Yun-Feng Xiao</a>, <a href="/search/quant-ph?searchtype=author&query=Huber%2C+M">Marcus Huber</a>, <a href="/search/quant-ph?searchtype=author&query=Malik%2C+M">Mehul Malik</a>, <a href="/search/quant-ph?searchtype=author&query=Sinclair%2C+G+F">Gary F. Sinclair</a>, <a href="/search/quant-ph?searchtype=author&query=Zhou%2C+X">Xiaoqi Zhou</a>, <a href="/search/quant-ph?searchtype=author&query=Rottwitt%2C+K">Karsten Rottwitt</a>, <a href="/search/quant-ph?searchtype=author&query=Brien%2C+J+L+O">Jeremy L. O Brien</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+Q">Qihuang Gong</a>, <a href="/search/quant-ph?searchtype=author&query=Oxenlowe%2C+L+K">Leif K. Oxenlowe</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jianwei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Thompson%2C+M+G">Mark G. Thompson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1911.07839v2-abstract-short" style="display: inline;"> Exploiting semiconductor fabrication techniques, natural carriers of quantum information such as atoms, electrons, and photons can be embedded in scalable integrated devices. Integrated optics provides a versatile platform for large-scale quantum information processing and transceiving with photons. Scaling up the integrated devices for quantum applications requires highperformance single-photon g… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.07839v2-abstract-full').style.display = 'inline'; document.getElementById('1911.07839v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1911.07839v2-abstract-full" style="display: none;"> Exploiting semiconductor fabrication techniques, natural carriers of quantum information such as atoms, electrons, and photons can be embedded in scalable integrated devices. Integrated optics provides a versatile platform for large-scale quantum information processing and transceiving with photons. Scaling up the integrated devices for quantum applications requires highperformance single-photon generation and photonic qubit-qubit entangling operations. However, previous demonstrations report major challenges in producing multiple bright, pure and identical single-photons, and entangling multiple photonic qubits with high fidelity. Another notable challenge is to noiselessly interface multiphoton sources and multiqubit operators in a single device. Here we demonstrate on-chip genuine multipartite entanglement and quantum teleportation in silicon, by coherently controlling an integrated network of microresonator nonlinear single-photon sources and linear-optic multiqubit entangling circuits. The microresonators are engineered to locally enhance the nonlinearity, producing multiple frequencyuncorrelated and indistinguishable single-photons, without requiring any spectral filtering. The multiqubit states are processed in a programmable linear circuit facilitating Bell-projection and fusion operation in a measurement-based manner. We benchmark key functionalities, such as intra-/inter-chip teleportation of quantum states, and generation of four-photon Greenberger-HorneZeilinger entangled states. The production, control, and transceiving of states are all achieved in micrometer-scale silicon chips, fabricated by complementary metal-oxide-semiconductor processes. Our work lays the groundwork for scalable on-chip multiphoton technologies for quantum computing and communication. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.07839v2-abstract-full').style.display = 'none'; document.getElementById('1911.07839v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 November, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat. Phys. 16, 148-153 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.00649">arXiv:1910.00649</a> <span> [<a href="https://arxiv.org/pdf/1910.00649">pdf</a>, <a href="https://arxiv.org/format/1910.00649">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/OE.27.020787">10.1364/OE.27.020787 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Localization-based two-photon wave-function information encoding </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Santagati%2C+R">Raffaele Santagati</a>, <a href="/search/quant-ph?searchtype=author&query=Price%2C+A+B">Alasdair B. Price</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Leonetti%2C+M">Marco Leonetti</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1910.00649v2-abstract-short" style="display: inline;"> In quantum communications, quantum states are employed for the transmission of information between remote parties. This usually requires sharing knowledge of the measurement bases through a classical public channel in the sifting phase of the protocol. Here, we demonstrate a quantum communication scheme where the information on the bases is shared "non-classically", by encoding this information… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.00649v2-abstract-full').style.display = 'inline'; document.getElementById('1910.00649v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.00649v2-abstract-full" style="display: none;"> In quantum communications, quantum states are employed for the transmission of information between remote parties. This usually requires sharing knowledge of the measurement bases through a classical public channel in the sifting phase of the protocol. Here, we demonstrate a quantum communication scheme where the information on the bases is shared "non-classically", by encoding this information in the same photons used for carrying the data. This enhanced capability is achieved by exploiting the localization of the photonic wave function, observed when the photons are prepared and measured in the same quantum basis. We experimentally implement our scheme by using a multi-mode optical fiber coupled to an adaptive optics setup. We observe a decrease in the error rate for higher dimensionality, indicating an improved resilience against noise. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.00649v2-abstract-full').style.display = 'none'; document.getElementById('1910.00649v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Opt. Express 27, 20787-20799 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1909.09383">arXiv:1909.09383</a> <span> [<a href="https://arxiv.org/pdf/1909.09383">pdf</a>, <a href="https://arxiv.org/format/1909.09383">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/5.0002709">10.1063/5.0002709 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Single photon emission and single spin coherence of a nitrogen vacancy centre encapsulated in silicon nitride </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Smith%2C+J">Joe Smith</a>, <a href="/search/quant-ph?searchtype=author&query=Monroy-Ruz%2C+J">Jorge Monroy-Ruz</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Balram%2C+K+C">Krishna C. Balram</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1909.09383v2-abstract-short" style="display: inline;"> Finding the right material platform for engineering efficient photonic interfaces to solid state emitters has been a long-standing bottleneck for scaling up solid state quantum systems. In this work, we demonstrate that nitrogen-rich silicon nitride, with its low background auto-fluorescence at visible wavelengths, is a viable quantum photonics platform by showing that nitrogen vacancy centres emb… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.09383v2-abstract-full').style.display = 'inline'; document.getElementById('1909.09383v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.09383v2-abstract-full" style="display: none;"> Finding the right material platform for engineering efficient photonic interfaces to solid state emitters has been a long-standing bottleneck for scaling up solid state quantum systems. In this work, we demonstrate that nitrogen-rich silicon nitride, with its low background auto-fluorescence at visible wavelengths, is a viable quantum photonics platform by showing that nitrogen vacancy centres embedded in nanodiamonds preserve both their quantum optical and spin properties post-encapsulation. Given the variety of high-performance photonic components already demonstrated in silicon nitride, our work opens up a new avenue for building integrated photonic circuits using solid state emitters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.09383v2-abstract-full').style.display = 'none'; document.getElementById('1909.09383v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 4 figures. Results unchanged, arguments revised</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Appl. Phys. Lett. 116, 134001 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.08745">arXiv:1908.08745</a> <span> [<a href="https://arxiv.org/pdf/1908.08745">pdf</a>, <a href="https://arxiv.org/format/1908.08745">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/OPTICA.379679">10.1364/OPTICA.379679 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Chip-based measurement-device-independent quantum key distribution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Semenenko%2C+H">Henry Semenenko</a>, <a href="/search/quant-ph?searchtype=author&query=Sibson%2C+P">Philip Sibson</a>, <a href="/search/quant-ph?searchtype=author&query=Hart%2C+A">Andy Hart</a>, <a href="/search/quant-ph?searchtype=author&query=Thompson%2C+M+G">Mark G. Thompson</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Erven%2C+C">Chris Erven</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1908.08745v2-abstract-short" style="display: inline;"> Modern communication strives towards provably secure systems which can be widely deployed. Quantum key distribution provides a methodology to verify the integrity and security of a key exchange based on physical laws. However, physical systems often fall short of theoretical models, meaning they can be compromised through uncharacterized side-channels. The complexity of detection means that the me… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.08745v2-abstract-full').style.display = 'inline'; document.getElementById('1908.08745v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.08745v2-abstract-full" style="display: none;"> Modern communication strives towards provably secure systems which can be widely deployed. Quantum key distribution provides a methodology to verify the integrity and security of a key exchange based on physical laws. However, physical systems often fall short of theoretical models, meaning they can be compromised through uncharacterized side-channels. The complexity of detection means that the measurement system is a vulnerable target for an adversary. Here, we present secure key exchange up to 200 km while removing all side-channels from the measurement system. We use mass-manufacturable, monolithically integrated transmitters that represent an accessible, quantum-ready communication platform. This work demonstrates a network topology that allows secure equipment sharing which is accessible with a cost-effective transmitter, significantly reducing the barrier for widespread uptake of quantum-secured communication. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.08745v2-abstract-full').style.display = 'none'; document.getElementById('1908.08745v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 March, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Optica 7 (3), 238-242 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.08229">arXiv:1907.08229</a> <span> [<a href="https://arxiv.org/pdf/1907.08229">pdf</a>, <a href="https://arxiv.org/format/1907.08229">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/sciadv.aba0959">10.1126/sciadv.aba0959 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A trusted-node-free eight-user metropolitan quantum communication network </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+S+K">Siddarth Koduru Joshi</a>, <a href="/search/quant-ph?searchtype=author&query=Aktas%2C+D">Djeylan Aktas</a>, <a href="/search/quant-ph?searchtype=author&query=Wengerowsky%2C+S">S枚ren Wengerowsky</a>, <a href="/search/quant-ph?searchtype=author&query=Lon%C4%8Dari%C4%87%2C+M">Martin Lon膷ari膰</a>, <a href="/search/quant-ph?searchtype=author&query=Neumann%2C+S+P">Sebastian Philipp Neumann</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+B">Bo Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Scheidl%2C+T">Thomas Scheidl</a>, <a href="/search/quant-ph?searchtype=author&query=Curr%C3%A1s-Lorenzo%2C+G">Guillermo Curr谩s-Lorenzo</a>, <a href="/search/quant-ph?searchtype=author&query=Samec%2C+%C5%BD">沤eljko Samec</a>, <a href="/search/quant-ph?searchtype=author&query=Kling%2C+L">Laurent Kling</a>, <a href="/search/quant-ph?searchtype=author&query=Qiu%2C+A">Alex Qiu</a>, <a href="/search/quant-ph?searchtype=author&query=Razavi%2C+M">Mohsen Razavi</a>, <a href="/search/quant-ph?searchtype=author&query=Stip%C4%8Devi%C4%87%2C+M">Mario Stip膷evi膰</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Ursin%2C+R">Rupert Ursin</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1907.08229v4-abstract-short" style="display: inline;"> Quantum communication is rapidly gaining popularity due to its high security and technological maturity. However, most implementations are limited to just two communicating parties (users). Quantum communication networks aim to connect a multitude of users. Here we present a fully connected quantum communication network on a city wide scale without active switching or trusted nodes. We demonstrate… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.08229v4-abstract-full').style.display = 'inline'; document.getElementById('1907.08229v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.08229v4-abstract-full" style="display: none;"> Quantum communication is rapidly gaining popularity due to its high security and technological maturity. However, most implementations are limited to just two communicating parties (users). Quantum communication networks aim to connect a multitude of users. Here we present a fully connected quantum communication network on a city wide scale without active switching or trusted nodes. We demonstrate simultaneous and secure connections between all 28 pairings of 8 users. Our novel network topology is easily scalable to many users, allows traffic management features and minimises the infrastructure as well as the user hardware needed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.08229v4-abstract-full').style.display = 'none'; document.getElementById('1907.08229v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 9 figures, 3 tables. Corrected typos, updated references</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science Advances 6, no. 36 (2020): eaba0959 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.10158">arXiv:1906.10158</a> <span> [<a href="https://arxiv.org/pdf/1906.10158">pdf</a>, <a href="https://arxiv.org/format/1906.10158">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/OE.386615">10.1364/OE.386615 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Mid-infrared quantum optics in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Rosenfeld%2C+L+M">Lawrence M. Rosenfeld</a>, <a href="/search/quant-ph?searchtype=author&query=Sulway%2C+D+A">Dominic A. Sulway</a>, <a href="/search/quant-ph?searchtype=author&query=Sinclair%2C+G+F">Gary F. Sinclair</a>, <a href="/search/quant-ph?searchtype=author&query=Anant%2C+V">Vikas Anant</a>, <a href="/search/quant-ph?searchtype=author&query=Thompson%2C+M+G">Mark G. Thompson</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Silverstone%2C+J+W">Joshua W. Silverstone</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1906.10158v2-abstract-short" style="display: inline;"> Applied quantum optics stands to revolutionise many aspects of information technology, provided performance can be maintained when scaled up. Silicon quantum photonics satisfies the scaling requirements of miniaturisation and manufacturability, but at 1.55 $渭$m it suffers from unacceptable linear and nonlinear loss. Here we show that, by translating silicon quantum photonics to the mid-infrared, a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.10158v2-abstract-full').style.display = 'inline'; document.getElementById('1906.10158v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.10158v2-abstract-full" style="display: none;"> Applied quantum optics stands to revolutionise many aspects of information technology, provided performance can be maintained when scaled up. Silicon quantum photonics satisfies the scaling requirements of miniaturisation and manufacturability, but at 1.55 $渭$m it suffers from unacceptable linear and nonlinear loss. Here we show that, by translating silicon quantum photonics to the mid-infrared, a new quantum optics platform is created which can simultaneously maximise manufacturability and miniaturisation, while minimising loss. We demonstrate the necessary platform components: photon-pair generation, single-photon detection, and high-visibility quantum interference, all at wavelengths beyond 2 $渭$m. Across various regimes, we observe a maximum net coincidence rate of 448 $\pm$ 12 Hz, a coincidence-to-accidental ratio of 25.7 $\pm$ 1.1, and, a net two photon quantum interference visibility of 0.993 $\pm$ 0.017. Mid-infrared silicon quantum photonics will bring new quantum applications within reach. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.10158v2-abstract-full').style.display = 'none'; document.getElementById('1906.10158v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures; revised figures, updated discussion in section 3, typos corrected, added reference</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.05331">arXiv:1906.05331</a> <span> [<a href="https://arxiv.org/pdf/1906.05331">pdf</a>, <a href="https://arxiv.org/format/1906.05331">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Twin-beam sub-shot-noise raster-scanning microscope with a hybrid detection scheme </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Sabines-Chesterking%2C+J">J. Sabines-Chesterking</a>, <a href="/search/quant-ph?searchtype=author&query=McMillan%2C+A+R">A. R. McMillan</a>, <a href="/search/quant-ph?searchtype=author&query=Moreau%2C+P+A">P. A. Moreau</a>, <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+S+K">S. K. Joshi</a>, <a href="/search/quant-ph?searchtype=author&query=Knauer%2C+S">S. Knauer</a>, <a href="/search/quant-ph?searchtype=author&query=Johnston%2C+E">E. Johnston</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Matthews%2C+J+C+F">J. C. F. Matthews</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1906.05331v1-abstract-short" style="display: inline;"> By exploiting the quantised nature of light, we demonstrate a sub-shot-noise scanning optical transmittance microscope. Our microscope demonstrates, with micron scale resolution, a factor of improvement in precision of 1.76(9) in transmittance estimation gained per probe photon relative to an optimal classical version at the same optical power. This would allow us to observe photosensitive samples… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.05331v1-abstract-full').style.display = 'inline'; document.getElementById('1906.05331v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.05331v1-abstract-full" style="display: none;"> By exploiting the quantised nature of light, we demonstrate a sub-shot-noise scanning optical transmittance microscope. Our microscope demonstrates, with micron scale resolution, a factor of improvement in precision of 1.76(9) in transmittance estimation gained per probe photon relative to an optimal classical version at the same optical power. This would allow us to observe photosensitive samples with nearly twice the precision,without sacrificing image resolution or increasing optical power to improve signal-to-noise ratio. Our setup uses correlated twin-beams produced by parametric down-conversion, and a hybrid detection scheme comprising photon-counting-based feed-forward and a highly efficient CCD camera. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.05331v1-abstract-full').style.display = 'none'; document.getElementById('1906.05331v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.09753">arXiv:1807.09753</a> <span> [<a href="https://arxiv.org/pdf/1807.09753">pdf</a>, <a href="https://arxiv.org/format/1807.09753">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevX.9.021019">10.1103/PhysRevX.9.021019 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetic-field-learning using a single electronic spin in diamond with one-photon-readout at room temperature </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Santagati%2C+R">Raffaele Santagati</a>, <a href="/search/quant-ph?searchtype=author&query=Gentile%2C+A+A">Antonio A. Gentile</a>, <a href="/search/quant-ph?searchtype=author&query=Knauer%2C+S">Sebastian Knauer</a>, <a href="/search/quant-ph?searchtype=author&query=Schmitt%2C+S">Simon Schmitt</a>, <a href="/search/quant-ph?searchtype=author&query=Paesani%2C+S">Stefano Paesani</a>, <a href="/search/quant-ph?searchtype=author&query=Granade%2C+C">Christopher Granade</a>, <a href="/search/quant-ph?searchtype=author&query=Wiebe%2C+N">Nathan Wiebe</a>, <a href="/search/quant-ph?searchtype=author&query=Osterkamp%2C+C">Christian Osterkamp</a>, <a href="/search/quant-ph?searchtype=author&query=McGuinness%2C+L+P">Liam P. McGuinness</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jianwei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Thompson%2C+M+G">Mark G. Thompson</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Jelezko%2C+F">Fedor Jelezko</a>, <a href="/search/quant-ph?searchtype=author&query=Laing%2C+A">Anthony Laing</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1807.09753v1-abstract-short" style="display: inline;"> Nitrogen-vacancy (NV) centres in diamond are appealing nano-scale quantum sensors for temperature, strain, electric fields and, most notably, for magnetic fields. However, the cryogenic temperatures required for low-noise single-shot readout that have enabled the most sensitive NV-magnetometry reported to date, are impractical for key applications, e.g. biological sensing. Overcoming the noisy rea… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.09753v1-abstract-full').style.display = 'inline'; document.getElementById('1807.09753v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.09753v1-abstract-full" style="display: none;"> Nitrogen-vacancy (NV) centres in diamond are appealing nano-scale quantum sensors for temperature, strain, electric fields and, most notably, for magnetic fields. However, the cryogenic temperatures required for low-noise single-shot readout that have enabled the most sensitive NV-magnetometry reported to date, are impractical for key applications, e.g. biological sensing. Overcoming the noisy readout at room-temperature has until now demanded repeated collection of fluorescent photons, which increases the time-cost of the procedure thus reducing its sensitivity. Here we show how machine learning can process the noisy readout of a single NV centre at room-temperature, requiring on average only one photon per algorithm step, to sense magnetic field strength with a precision comparable to those reported for cryogenic experiments. Analysing large data sets from NV centres in bulk diamond, we report absolute sensitivities of $60$ nT s$^{1/2}$ including initialisation, readout, and computational overheads. We show that dephasing times can be simultaneously estimated, and that time-dependent fields can be dynamically tracked at room temperature. Our results dramatically increase the practicality of early-term single spin sensors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.09753v1-abstract-full').style.display = 'none'; document.getElementById('1807.09753v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">including supplementary informations</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. X 9, 021019 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1707.03331">arXiv:1707.03331</a> <span> [<a href="https://arxiv.org/pdf/1707.03331">pdf</a>, <a href="https://arxiv.org/format/1707.03331">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cryptography and Security">cs.CR</span> </div> </div> <p class="title is-5 mathjax"> A quantum key distribution protocol for rapid denial of service detection </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Price%2C+A+B">Alasdair B. Price</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Erven%2C+C">Chris Erven</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1707.03331v2-abstract-short" style="display: inline;"> We introduce a quantum key distribution protocol designed to expose fake users that connect to Alice or Bob for the purpose of monopolising the link and denying service. It inherently resists attempts to exhaust Alice and Bob's initial shared secret, and is 100% efficient, regardless of the number of qubits exchanged above the finite key limit. Additionally, secure key can be generated from two-ph… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.03331v2-abstract-full').style.display = 'inline'; document.getElementById('1707.03331v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1707.03331v2-abstract-full" style="display: none;"> We introduce a quantum key distribution protocol designed to expose fake users that connect to Alice or Bob for the purpose of monopolising the link and denying service. It inherently resists attempts to exhaust Alice and Bob's initial shared secret, and is 100% efficient, regardless of the number of qubits exchanged above the finite key limit. Additionally, secure key can be generated from two-photon pulses, without having to make any extra modifications. This is made possible by relaxing the security of BB84 to that of the quantum-safe block cipher used for day-to-day encryption, meaning the overall security remains unaffected for useful real-world cryptosystems such as AES-GCM being keyed with quantum devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1707.03331v2-abstract-full').style.display = 'none'; document.getElementById('1707.03331v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 November, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 July, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 3 figures. v2: Shifted focus of paper towards DoS and added protocol 4. v1: Accepted to QCrypt 2017</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1705.03032">arXiv:1705.03032</a> <span> [<a href="https://arxiv.org/pdf/1705.03032">pdf</a>, <a href="https://arxiv.org/format/1705.03032">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1367-2630/aa9b5c">10.1088/1367-2630/aa9b5c <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental demonstration of a measurement-based realisation of a quantum channel </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=McCutcheon%2C+W">W. McCutcheon</a>, <a href="/search/quant-ph?searchtype=author&query=McMillan%2C+A">A. McMillan</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Tame%2C+M+S">M. S. Tame</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1705.03032v2-abstract-short" style="display: inline;"> We introduce and experimentally demonstrate a method for realising a quantum channel using the measurement-based model. Using a photonic setup and modifying the bases of single-qubit measurements on a four-qubit entangled cluster state, representative channels are realised for the case of a single qubit in the form of amplitude and phase damping channels. The experimental results match the theoret… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.03032v2-abstract-full').style.display = 'inline'; document.getElementById('1705.03032v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1705.03032v2-abstract-full" style="display: none;"> We introduce and experimentally demonstrate a method for realising a quantum channel using the measurement-based model. Using a photonic setup and modifying the bases of single-qubit measurements on a four-qubit entangled cluster state, representative channels are realised for the case of a single qubit in the form of amplitude and phase damping channels. The experimental results match the theoretical model well, demonstrating the successful performance of the channels. We also show how other types of quantum channels can be realised using our approach. This work highlights the potential of the measurement-based model for realising quantum channels which may serve as building blocks for simulations of realistic open quantum systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.03032v2-abstract-full').style.display = 'none'; document.getElementById('1705.03032v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 April, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> New J. Phys. 20, 033019 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1705.01029">arXiv:1705.01029</a> <span> [<a href="https://arxiv.org/pdf/1705.01029">pdf</a>, <a href="https://arxiv.org/format/1705.01029">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/OE.26.020379">10.1364/OE.26.020379 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On-chip quantum interference with heralded photons from two independent micro-ring resonator sources in silicon photonics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Faruque%2C+I+I">Imad I. Faruque</a>, <a href="/search/quant-ph?searchtype=author&query=Sinclair%2C+G+F">Gary F. Sinclair</a>, <a href="/search/quant-ph?searchtype=author&query=Bonneau%2C+D">Damien Bonneau</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Thompson%2C+M+G">Mark G. Thompson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1705.01029v2-abstract-short" style="display: inline;"> High visibility on-chip quantum interference among indistinguishable single-photons from multiples sources is a key prerequisite for integrated linear optical quantum computing. Resonant enhancement in micro-ring resonators naturally enables brighter, purer and more indistinguishable single-photon production without any tight spectral filtering. The indistinguishability of heralded single-photons… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.01029v2-abstract-full').style.display = 'inline'; document.getElementById('1705.01029v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1705.01029v2-abstract-full" style="display: none;"> High visibility on-chip quantum interference among indistinguishable single-photons from multiples sources is a key prerequisite for integrated linear optical quantum computing. Resonant enhancement in micro-ring resonators naturally enables brighter, purer and more indistinguishable single-photon production without any tight spectral filtering. The indistinguishability of heralded single-photons from multiple micro-ring resonators has not been measured in any photonic platform. Here, we report on-chip indistinguishability measurements of heralded single-photons generated from independent micro-ring resonators by using an on-chip Mach-Zehnder interferometer and spectral demultiplexer. We measured the raw heralded two-photon interference fringe visibility as 72 +/- 3%. This result agrees with our model, which includes device imperfections, spectral impurity and multi-pair emissions. We identify multi-pair emissions as the main factor limiting the nonclassical interference visibility, and show a route towards achieving near unity visibility in future experiments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.01029v2-abstract-full').style.display = 'none'; document.getElementById('1705.01029v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Optics Express Vol. 26, Issue 16, pp. 20379-20395 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1703.05402">arXiv:1703.05402</a> <span> [<a href="https://arxiv.org/pdf/1703.05402">pdf</a>, <a href="https://arxiv.org/format/1703.05402">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nphys4074">10.1038/nphys4074 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental Quantum Hamiltonian Learning </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+J">Jianwei Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Paesani%2C+S">Stefano Paesani</a>, <a href="/search/quant-ph?searchtype=author&query=Santagati%2C+R">Raffaele Santagati</a>, <a href="/search/quant-ph?searchtype=author&query=Knauer%2C+S">Sebastian Knauer</a>, <a href="/search/quant-ph?searchtype=author&query=Gentile%2C+A+A">Antonio A. Gentile</a>, <a href="/search/quant-ph?searchtype=author&query=Wiebe%2C+N">Nathan Wiebe</a>, <a href="/search/quant-ph?searchtype=author&query=Petruzzella%2C+M">Maurangelo Petruzzella</a>, <a href="/search/quant-ph?searchtype=author&query=O%27Brien%2C+J+L">Jeremy L. O'Brien</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Laing%2C+A">Anthony Laing</a>, <a href="/search/quant-ph?searchtype=author&query=Thompson%2C+M+G">Mark G. Thompson</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1703.05402v1-abstract-short" style="display: inline;"> Efficiently characterising quantum systems, verifying operations of quantum devices and validating underpinning physical models, are central challenges for the development of quantum technologies and for our continued understanding of foundational physics. Machine-learning enhanced by quantum simulators has been proposed as a route to improve the computational cost of performing these studies. Her… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.05402v1-abstract-full').style.display = 'inline'; document.getElementById('1703.05402v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1703.05402v1-abstract-full" style="display: none;"> Efficiently characterising quantum systems, verifying operations of quantum devices and validating underpinning physical models, are central challenges for the development of quantum technologies and for our continued understanding of foundational physics. Machine-learning enhanced by quantum simulators has been proposed as a route to improve the computational cost of performing these studies. Here we interface two different quantum systems through a classical channel - a silicon-photonics quantum simulator and an electron spin in a diamond nitrogen-vacancy centre - and use the former to learn the latter's Hamiltonian via Bayesian inference. We learn the salient Hamiltonian parameter with an uncertainty of approximately $10^{-5}$. Furthermore, an observed saturation in the learning algorithm suggests deficiencies in the underlying Hamiltonian model, which we exploit to further improve the model itself. We go on to implement an interactive version of the protocol and experimentally show its ability to characterise the operation of the quantum photonic device. This work demonstrates powerful new quantum-enhanced techniques for investigating foundational physical models and characterising quantum technologies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.05402v1-abstract-full').style.display = 'none'; document.getElementById('1703.05402v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Physics 13, 551-555 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1611.07871">arXiv:1611.07871</a> <span> [<a href="https://arxiv.org/pdf/1611.07871">pdf</a>, <a href="https://arxiv.org/ps/1611.07871">ps</a>, <a href="https://arxiv.org/format/1611.07871">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> </div> <p class="title is-5 mathjax"> Demonstrating an absolute quantum advantage in direct absorption measurement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Moreau%2C+P">Paul-Antoine Moreau</a>, <a href="/search/quant-ph?searchtype=author&query=Sabines-Chesterking%2C+J">Javier Sabines-Chesterking</a>, <a href="/search/quant-ph?searchtype=author&query=Whittaker%2C+R">Rebecca Whittaker</a>, <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+S+K">Siddarth K. Joshi</a>, <a href="/search/quant-ph?searchtype=author&query=Birchall%2C+P">Patrick Birchall</a>, <a href="/search/quant-ph?searchtype=author&query=McMillan%2C+A">Alex McMillan</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Matthews%2C+J+C+F">Jonathan C. F. Matthews</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1611.07871v1-abstract-short" style="display: inline;"> Engineering apparatus that harness quantum theory offers practical advantages over current technology. A fundamentally more powerful prospect is the long-standing prediction that such quantum technologies could out-perform any future iteration of their classical counterparts, no matter how well the attributes of those classical strategies can be improved. Here, we experimentally demonstrate such a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.07871v1-abstract-full').style.display = 'inline'; document.getElementById('1611.07871v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1611.07871v1-abstract-full" style="display: none;"> Engineering apparatus that harness quantum theory offers practical advantages over current technology. A fundamentally more powerful prospect is the long-standing prediction that such quantum technologies could out-perform any future iteration of their classical counterparts, no matter how well the attributes of those classical strategies can be improved. Here, we experimentally demonstrate such an instance of \textit{absolute} advantage per photon probe in the precision of optical direct absorption measurement. We use correlated intensity measurements of spontaneous parametric downconversion using a commercially available air-cooled CCD, a new estimator for data analysis and a high heralding efficiency photon-pair source. We show this enables improvement in the precision of measurement, per photon probe, beyond what is achievable with an ideal coherent state (a perfect laser) detected with $100\%$ efficient and noiseless detection. We see this absolute improvement for up to $50\%$ absorption, with a maximum observed factor of improvement of 1.46. This equates to around $32\%$ reduction in the total number of photons traversing an optical sample, compared to any future direct optical absorption measurement using classical light. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.07871v1-abstract-full').style.display = 'none'; document.getElementById('1611.07871v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 November, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2016. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1611.07870">arXiv:1611.07870</a> <span> [<a href="https://arxiv.org/pdf/1611.07870">pdf</a>, <a href="https://arxiv.org/format/1611.07870">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevApplied.8.014016">10.1103/PhysRevApplied.8.014016 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Sub-shot-noise transmission measurement using optically gated single photons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Sabines-Chesterking%2C+J">J. Sabines-Chesterking</a>, <a href="/search/quant-ph?searchtype=author&query=Whittaker%2C+R">R. Whittaker</a>, <a href="/search/quant-ph?searchtype=author&query=Joshi%2C+S+K">S. K. Joshi</a>, <a href="/search/quant-ph?searchtype=author&query=Birchall%2C+P+M">P. M. Birchall</a>, <a href="/search/quant-ph?searchtype=author&query=Moreau%2C+P+A">P. A. Moreau</a>, <a href="/search/quant-ph?searchtype=author&query=McMillan%2C+A">A. McMillan</a>, <a href="/search/quant-ph?searchtype=author&query=Cable%2C+H+V">H. V. Cable</a>, <a href="/search/quant-ph?searchtype=author&query=O%27Brien%2C+J+L">J. L. O'Brien</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Matthews%2C+J+C+F">J. C. F. Matthews</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1611.07870v1-abstract-short" style="display: inline;"> Harnessing the unique properties of quantum mechanics offers the possibility to deliver new technologies that can fundamentally outperform their classical counterparts. These technologies only deliver advantages when components operate with performance beyond specific thresholds. For optical quantum metrology, the biggest challenge that impacts on performance thresholds is optical loss. Here we de… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.07870v1-abstract-full').style.display = 'inline'; document.getElementById('1611.07870v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1611.07870v1-abstract-full" style="display: none;"> Harnessing the unique properties of quantum mechanics offers the possibility to deliver new technologies that can fundamentally outperform their classical counterparts. These technologies only deliver advantages when components operate with performance beyond specific thresholds. For optical quantum metrology, the biggest challenge that impacts on performance thresholds is optical loss. Here we demonstrate how including an optical delay and an optical switch in a feed-forward configuration with a stable and efficient correlated photon pair source reduces the detector efficiency required to enable quantum enhanced sensing down to the detection level of single photons. When the switch is active, we observe a factor of improvement in precision of 1.27 for transmission measurement on a per input photon basis, compared to the performance of a laser emitting an ideal coherent state and measured with the same detection efficiency as our setup. When the switch is inoperative, we observe no quantum advantage. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.07870v1-abstract-full').style.display = 'none'; document.getElementById('1611.07870v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 November, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Applied 8, 014016 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1611.04772">arXiv:1611.04772</a> <span> [<a href="https://arxiv.org/pdf/1611.04772">pdf</a>, <a href="https://arxiv.org/format/1611.04772">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/ncomms13251">10.1038/ncomms13251 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental Verification of Multipartite Entanglement in Quantum Networks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=McCutcheon%2C+W">W. McCutcheon</a>, <a href="/search/quant-ph?searchtype=author&query=Pappa%2C+A">A. Pappa</a>, <a href="/search/quant-ph?searchtype=author&query=Bell%2C+B+A">B. A. Bell</a>, <a href="/search/quant-ph?searchtype=author&query=McMillan%2C+A">A. McMillan</a>, <a href="/search/quant-ph?searchtype=author&query=Chailloux%2C+A">A. Chailloux</a>, <a href="/search/quant-ph?searchtype=author&query=Lawson%2C+T">T. Lawson</a>, <a href="/search/quant-ph?searchtype=author&query=Mafu%2C+M">M. Mafu</a>, <a href="/search/quant-ph?searchtype=author&query=Markham%2C+D">D. Markham</a>, <a href="/search/quant-ph?searchtype=author&query=Diamanti%2C+E">E. Diamanti</a>, <a href="/search/quant-ph?searchtype=author&query=Kerenidis%2C+I">I. Kerenidis</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Tame%2C+M+S">M. S. Tame</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1611.04772v1-abstract-short" style="display: inline;"> Multipartite entangled states are a fundamental resource for a wide range of quantum information processing tasks. In particular, in quantum networks it is essential for the parties involved to be able to verify if entanglement is present before they carry out a given distributed task. Here we design and experimentally demonstrate a protocol that allows any party in a network to check if a source… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.04772v1-abstract-full').style.display = 'inline'; document.getElementById('1611.04772v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1611.04772v1-abstract-full" style="display: none;"> Multipartite entangled states are a fundamental resource for a wide range of quantum information processing tasks. In particular, in quantum networks it is essential for the parties involved to be able to verify if entanglement is present before they carry out a given distributed task. Here we design and experimentally demonstrate a protocol that allows any party in a network to check if a source is distributing a genuinely multipartite entangled state, even in the presence of untrusted parties. The protocol remains secure against dishonest behaviour of the source and other parties, including the use of system imperfections to their advantage. We demonstrate the verification protocol in a three- and four-party setting using polarization-entangled photons, highlighting its potential for realistic photonic quantum communication and networking applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.04772v1-abstract-full').style.display = 'none'; document.getElementById('1611.04772v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 November, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 7, 13251 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1611.01189">arXiv:1611.01189</a> <span> [<a href="https://arxiv.org/pdf/1611.01189">pdf</a>, <a href="https://arxiv.org/format/1611.01189">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/2058-9565/aa6ae2">10.1088/2058-9565/aa6ae2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimentally exploring compressed sensing quantum tomography </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Steffens%2C+A">A. Steffens</a>, <a href="/search/quant-ph?searchtype=author&query=Riofrio%2C+C">C. Riofrio</a>, <a href="/search/quant-ph?searchtype=author&query=McCutcheon%2C+W">W. McCutcheon</a>, <a href="/search/quant-ph?searchtype=author&query=Roth%2C+I">I. Roth</a>, <a href="/search/quant-ph?searchtype=author&query=Bell%2C+B+A">B. A. Bell</a>, <a href="/search/quant-ph?searchtype=author&query=McMillan%2C+A">A. McMillan</a>, <a href="/search/quant-ph?searchtype=author&query=Tame%2C+M+S">M. S. Tame</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Eisert%2C+J">J. Eisert</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1611.01189v2-abstract-short" style="display: inline;"> In the light of the progress in quantum technologies, the task of verifying the correct functioning of processes and obtaining accurate tomographic information about quantum states becomes increasingly important. Compressed sensing, a machinery derived from the theory of signal processing, has emerged as a feasible tool to perform robust and significantly more resource-economical quantum state tom… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.01189v2-abstract-full').style.display = 'inline'; document.getElementById('1611.01189v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1611.01189v2-abstract-full" style="display: none;"> In the light of the progress in quantum technologies, the task of verifying the correct functioning of processes and obtaining accurate tomographic information about quantum states becomes increasingly important. Compressed sensing, a machinery derived from the theory of signal processing, has emerged as a feasible tool to perform robust and significantly more resource-economical quantum state tomography for intermediate-sized quantum systems. In this work, we provide a comprehensive analysis of compressed sensing tomography in the regime in which tomographically complete data is available with reliable statistics from experimental observations of a multi-mode photonic architecture. Due to the fact that the data is known with high statistical significance, we are in a position to systematically explore the quality of reconstruction depending on the number of employed measurement settings, randomly selected from the complete set of data, and on different model assumptions. We present and test a complete prescription to perform efficient compressed sensing and are able to reliably use notions of model selection and cross-validation to account for experimental imperfections and finite counting statistics. Thus, we establish compressed sensing as an effective tool for quantum state tomography, specifically suited for photonic systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.01189v2-abstract-full').style.display = 'none'; document.getElementById('1611.01189v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 November, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 November, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Quantum Sci. Technol. 2, 025005 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1610.09954">arXiv:1610.09954</a> <span> [<a href="https://arxiv.org/pdf/1610.09954">pdf</a>, <a href="https://arxiv.org/format/1610.09954">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1209/0295-5075/116/64007">10.1209/0295-5075/116/64007 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Modelling Defect Cavities Formed in Inverse Three-Dimensional Rod-Connected Diamond Photonic Crystals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Taverne%2C+M+P+C">M. P. C. Taverne</a>, <a href="/search/quant-ph?searchtype=author&query=Ho%2C+Y+-+D">Y. -L. D. Ho</a>, <a href="/search/quant-ph?searchtype=author&query=Zheng%2C+X">X. Zheng</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+S">S. Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+L+-">L. -F. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Lopez-Garcia%2C+M">M. Lopez-Garcia</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1610.09954v2-abstract-short" style="display: inline;"> Defect cavities in 3D photonic crystal can trap and store light in the smallest volumes allowable in dielectric materials, enhancing non-linearities and cavity QED effects. Here, we study inverse rod-connected diamond (RCD) crystals containing point defect cavities using plane-wave expansion and finite-difference time domain methods. By optimizing the dimensions of the crystal, wide photonic band… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.09954v2-abstract-full').style.display = 'inline'; document.getElementById('1610.09954v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1610.09954v2-abstract-full" style="display: none;"> Defect cavities in 3D photonic crystal can trap and store light in the smallest volumes allowable in dielectric materials, enhancing non-linearities and cavity QED effects. Here, we study inverse rod-connected diamond (RCD) crystals containing point defect cavities using plane-wave expansion and finite-difference time domain methods. By optimizing the dimensions of the crystal, wide photonic band gaps are obtained. Mid-bandgap resonances can then be engineered by introducing point defects in the crystal. We investigate a variety of single spherical defects at different locations in the unit cell focusing on high-refractive-index contrast (3.3:1) inverse RCD structures; quality factors (Q-factors) and mode volumes of the resonant cavity modes are calculated. By choosing a symmetric arrangement, consisting of a single sphere defect located at the center of a tetrahedral arrangement, mode volumes < 0.06 cubic wavelengths are obtained, a record for high index cavities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.09954v2-abstract-full').style.display = 'none'; document.getElementById('1610.09954v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 January, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, 8 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.02851">arXiv:1609.02851</a> <span> [<a href="https://arxiv.org/pdf/1609.02851">pdf</a>, <a href="https://arxiv.org/format/1609.02851">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acsphotonics.8b01380">10.1021/acsphotonics.8b01380 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Efficient deterministic giant photon phase shift from a single charged quantum dot </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Androvitsaneas%2C+P">P. Androvitsaneas</a>, <a href="/search/quant-ph?searchtype=author&query=Young%2C+A+B">A. B. Young</a>, <a href="/search/quant-ph?searchtype=author&query=Lennon%2C+J+M">J. M. Lennon</a>, <a href="/search/quant-ph?searchtype=author&query=Schneider%2C+C">C. Schneider</a>, <a href="/search/quant-ph?searchtype=author&query=Maier%2C+S">S. Maier</a>, <a href="/search/quant-ph?searchtype=author&query=Hinchliff%2C+J+J">J. J. Hinchliff</a>, <a href="/search/quant-ph?searchtype=author&query=Atkinson%2C+G">G. Atkinson</a>, <a href="/search/quant-ph?searchtype=author&query=Kamp%2C+M">M. Kamp</a>, <a href="/search/quant-ph?searchtype=author&query=H%C3%B6fling%2C+S">S. H枚fling</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Oulton%2C+R">R. Oulton</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1609.02851v2-abstract-short" style="display: inline;"> Solid-state quantum emitters have long been recognised as the ideal platform to realize integrated quantum photonic technologies. We use a self-assembled negatively charged QD in a low Q-factor photonic micropillar to demonstrate for the first time a key figure of merit for deterministic switching and spin-photon entanglement: a shift in phase of an input single photon of $>90^{o}$ with values of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.02851v2-abstract-full').style.display = 'inline'; document.getElementById('1609.02851v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.02851v2-abstract-full" style="display: none;"> Solid-state quantum emitters have long been recognised as the ideal platform to realize integrated quantum photonic technologies. We use a self-assembled negatively charged QD in a low Q-factor photonic micropillar to demonstrate for the first time a key figure of merit for deterministic switching and spin-photon entanglement: a shift in phase of an input single photon of $>90^{o}$ with values of up to $2蟺/3$ ($120^{o}$) demonstrated. This $>蟺/2$ ($90^{o}$) measured value represents an important threshold: above this value input photons interact with the emitter deterministically. A deterministic photon-emitter interaction is the only viable scalable means to achieve several vital functionalities not possible in linear optics such as quantum switches and entanglement gates. Our experimentally determined value is limited by mode mismatch between the input laser and the cavity, QD spectral fluctuations and spin relaxation. We determine that up to $80\%$ of the collected photons have interacted with the QD and undergone a phase shift of $蟺$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.02851v2-abstract-full').style.display = 'none'; document.getElementById('1609.02851v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Supplementary information is available upon request</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1606.05109">arXiv:1606.05109</a> <span> [<a href="https://arxiv.org/pdf/1606.05109">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nphoton.2016.234">10.1038/nphoton.2016.234 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Laser writing of coherent colour centres in diamond </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu-Chen Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Salter%2C+P+S">Patrick S. Salter</a>, <a href="/search/quant-ph?searchtype=author&query=Knauer%2C+S">Sebastian Knauer</a>, <a href="/search/quant-ph?searchtype=author&query=Weng%2C+L">Laiyi Weng</a>, <a href="/search/quant-ph?searchtype=author&query=Frangeskou%2C+A+C">Angelo C. Frangeskou</a>, <a href="/search/quant-ph?searchtype=author&query=Stephen%2C+C+J">Colin J. Stephen</a>, <a href="/search/quant-ph?searchtype=author&query=Dolan%2C+P+R">Philip R. Dolan</a>, <a href="/search/quant-ph?searchtype=author&query=Johnson%2C+S">Sam Johnson</a>, <a href="/search/quant-ph?searchtype=author&query=Green%2C+B+L">Ben L. Green</a>, <a href="/search/quant-ph?searchtype=author&query=Morley%2C+G+W">Gavin W. Morley</a>, <a href="/search/quant-ph?searchtype=author&query=Newton%2C+M+E">Mark E. Newton</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Booth%2C+M+J">Martin J. Booth</a>, <a href="/search/quant-ph?searchtype=author&query=Smith%2C+J+M">Jason M. Smith</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1606.05109v1-abstract-short" style="display: inline;"> Optically active point defects in crystals have gained widespread attention as photonic systems that can find use in quantum information technologies. However challenges remain in the placing of individual defects at desired locations, an essential element of device fabrication. Here we report the controlled generation of single nitrogen-vacancy (NV) centres in diamond using laser writing. The use… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.05109v1-abstract-full').style.display = 'inline'; document.getElementById('1606.05109v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1606.05109v1-abstract-full" style="display: none;"> Optically active point defects in crystals have gained widespread attention as photonic systems that can find use in quantum information technologies. However challenges remain in the placing of individual defects at desired locations, an essential element of device fabrication. Here we report the controlled generation of single nitrogen-vacancy (NV) centres in diamond using laser writing. The use of aberration correction in the writing optics allows precise positioning of vacancies within the diamond crystal, and subsequent annealing produces single NV centres with up to 45% success probability, within about 200 nm of the desired position. Selected NV centres fabricated by this method display stable, coherent optical transitions at cryogenic temperatures, a pre-requisite for the creation of distributed quantum networks of solid-state qubits. The results illustrate the potential of laser writing as a new tool for defect engineering in quantum technologies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.05109v1-abstract-full').style.display = 'none'; document.getElementById('1606.05109v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 June, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages including Supplementary information</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Photonics 11, 77 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1511.08776">arXiv:1511.08776</a> <span> [<a href="https://arxiv.org/pdf/1511.08776">pdf</a>, <a href="https://arxiv.org/format/1511.08776">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.93.241409">10.1103/PhysRevB.93.241409 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A charged quantum dot micropillar system for deterministic light matter interactions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Androvitsaneas%2C+P">Petros Androvitsaneas</a>, <a href="/search/quant-ph?searchtype=author&query=Young%2C+A+B">Andrew B. Young</a>, <a href="/search/quant-ph?searchtype=author&query=Schneider%2C+C">Chritian Schneider</a>, <a href="/search/quant-ph?searchtype=author&query=Maier%2C+S">Sebastian Maier</a>, <a href="/search/quant-ph?searchtype=author&query=Kamp%2C+M">Martin Kamp</a>, <a href="/search/quant-ph?searchtype=author&query=H%C3%B6fling%2C+S">Sven H枚fling</a>, <a href="/search/quant-ph?searchtype=author&query=Knauer%2C+S">Sebastian Knauer</a>, <a href="/search/quant-ph?searchtype=author&query=Harbord%2C+E">Edmund Harbord</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+C">Cheng-Yong Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Oulton%2C+R">Ruth Oulton</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1511.08776v1-abstract-short" style="display: inline;"> Quantum dots (QDs) are semiconductor nanostructures in which a three dimensional potential trap produces an electronic quantum confinement, thus mimicking the behaviour of single atomic dipole-like transitions. However unlike atoms, QDs can be incorporated into solid state photonic devices such as cavities or waveguides that enhance the light-matter interaction. A near unit efficiency light-matter… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.08776v1-abstract-full').style.display = 'inline'; document.getElementById('1511.08776v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1511.08776v1-abstract-full" style="display: none;"> Quantum dots (QDs) are semiconductor nanostructures in which a three dimensional potential trap produces an electronic quantum confinement, thus mimicking the behaviour of single atomic dipole-like transitions. However unlike atoms, QDs can be incorporated into solid state photonic devices such as cavities or waveguides that enhance the light-matter interaction. A near unit efficiency light-matter interaction is essential for deterministic, scalable quantum information (QI) devices. In this limit, a single photon input into the device will undergo a large rotation of the polarization of the light field due to the strong interaction with the QD. In this paper we measure a macroscopic ($\sim6^o$) phase shift of light as a result of the interaction with a negatively charged QD coupled to a low quality-factor (Q$\sim290$) pillar microcavity. This unexpectedly large rotation angle demonstrates this simple low Q-factor design would enable near deterministic light-matter interactions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.08776v1-abstract-full').style.display = 'none'; document.getElementById('1511.08776v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 November, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 93, 241409 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1411.5827">arXiv:1411.5827</a> <span> [<a href="https://arxiv.org/pdf/1411.5827">pdf</a>, <a href="https://arxiv.org/format/1411.5827">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/ncomms6480">10.1038/ncomms6480 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental demonstration of graph-state quantum secret sharing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bell%2C+B+A">B. A. Bell</a>, <a href="/search/quant-ph?searchtype=author&query=Markham%2C+D">D. Markham</a>, <a href="/search/quant-ph?searchtype=author&query=Herrera-Mart%C3%AD%2C+D+A">D. A. Herrera-Mart铆</a>, <a href="/search/quant-ph?searchtype=author&query=Marin%2C+A">A. Marin</a>, <a href="/search/quant-ph?searchtype=author&query=Wadsworth%2C+W+J">W. J. Wadsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Tame%2C+M+S">M. S. Tame</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1411.5827v1-abstract-short" style="display: inline;"> Distributed quantum communication and quantum computing offer many new opportunities for quantum information processing. Here networks based on highly nonlocal quantum resources with complex entanglement structures have been proposed for distributing, sharing and processing quantum information. Graph states in particular have emerged as powerful resources for such tasks using measurement-based tec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.5827v1-abstract-full').style.display = 'inline'; document.getElementById('1411.5827v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1411.5827v1-abstract-full" style="display: none;"> Distributed quantum communication and quantum computing offer many new opportunities for quantum information processing. Here networks based on highly nonlocal quantum resources with complex entanglement structures have been proposed for distributing, sharing and processing quantum information. Graph states in particular have emerged as powerful resources for such tasks using measurement-based techniques. We report an experimental demonstration of graph-state quantum secret sharing, an important primitive for a quantum network. We use an all-optical setup to encode quantum information into photons representing a five-qubit graph state. We are able to reliably encode, distribute and share quantum information between four parties. In our experiment we demonstrate the integration of three distinct secret sharing protocols, which allow for security and protocol parameters not possible with any single protocol alone. Our results show that graph states are a promising approach for sophisticated multi-layered protocols in quantum networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.5827v1-abstract-full').style.display = 'none'; document.getElementById('1411.5827v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 November, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 5, 5480 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1410.3859">arXiv:1410.3859</a> <span> [<a href="https://arxiv.org/pdf/1410.3859">pdf</a>, <a href="https://arxiv.org/format/1410.3859">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.113.200501">10.1103/PhysRevLett.113.200501 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental Realization of a One-way Quantum Computer Algorithm Solving Simon's Problem </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Tame%2C+M+S">M. S. Tame</a>, <a href="/search/quant-ph?searchtype=author&query=Bell%2C+B+A">B. A. Bell</a>, <a href="/search/quant-ph?searchtype=author&query=Di+Franco%2C+C">C. Di Franco</a>, <a href="/search/quant-ph?searchtype=author&query=Wadsworth%2C+W+J">W. J. Wadsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1410.3859v1-abstract-short" style="display: inline;"> We report an experimental demonstration of a one-way implementation of a quantum algorithm solving Simon's Problem - a black box period-finding problem which has an exponential gap between the classical and quantum runtime. Using an all-optical setup and modifying the bases of single-qubit measurements on a five-qubit cluster state, key representative functions of the logical two-qubit version's b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.3859v1-abstract-full').style.display = 'inline'; document.getElementById('1410.3859v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1410.3859v1-abstract-full" style="display: none;"> We report an experimental demonstration of a one-way implementation of a quantum algorithm solving Simon's Problem - a black box period-finding problem which has an exponential gap between the classical and quantum runtime. Using an all-optical setup and modifying the bases of single-qubit measurements on a five-qubit cluster state, key representative functions of the logical two-qubit version's black box can be queried and solved. To the best of our knowledge, this work represents the first experimental realization of the quantum algorithm solving Simon's Problem. The experimental results are in excellent agreement with the theoretical model, demonstrating the successful performance of the algorithm. With a view to scaling up to larger numbers of qubits, we analyze the resource requirements for an n-qubit version. This work helps highlight how one-way quantum computing provides a practical route to experimentally investigating the quantum-classical gap in the query complexity model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1410.3859v1-abstract-full').style.display = 'none'; document.getElementById('1410.3859v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 October, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 113, 200501 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1409.4209">arXiv:1409.4209</a> <span> [<a href="https://arxiv.org/pdf/1409.4209">pdf</a>, <a href="https://arxiv.org/format/1409.4209">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1364/JOSAB.32.000639">10.1364/JOSAB.32.000639 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigation of defect cavities formed in three-dimensional woodpile photonic crystals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Taverne%2C+M+P+C">Mike P. C. Taverne</a>, <a href="/search/quant-ph?searchtype=author&query=Ho%2C+Y+-+D">Y. -L. D. Ho</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1409.4209v4-abstract-short" style="display: inline;"> We report the optimisation of optical properties of single defects in three-dimensional (3D) face-centred-cubic (FCC) woodpile photonic crystal (PC) cavities by using plane-wave expansion (PWE) and finite-difference time-domain (FDTD) methods. By optimising the dimensions of a 3D woodpile PC, wide photonic band gaps (PBG) are created. Optical cavities with resonances in the bandgap arise when poin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.4209v4-abstract-full').style.display = 'inline'; document.getElementById('1409.4209v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1409.4209v4-abstract-full" style="display: none;"> We report the optimisation of optical properties of single defects in three-dimensional (3D) face-centred-cubic (FCC) woodpile photonic crystal (PC) cavities by using plane-wave expansion (PWE) and finite-difference time-domain (FDTD) methods. By optimising the dimensions of a 3D woodpile PC, wide photonic band gaps (PBG) are created. Optical cavities with resonances in the bandgap arise when point defects are introduced in the crystal. Three types of single defects are investigated in high refractive index contrast (Gallium Phosphide-Air) woodpile structures and Q-factors and mode volumes ($V_{eff}$) of the resonant cavity modes are calculated. We show that, by introducing an air buffer around a single defect, smaller mode volumes can be obtained. We demonstrate high Q-factors up to 700000 and cavity volumes down to $V_{eff}<0.2(位/n)^3$. The estimates of $Q$ and $V_{eff}$ are then used to quantify the enhancement of spontaneous emission and the possibility of achieving strong coupling with nitrogen-vacancy (NV) colour centres in diamond. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.4209v4-abstract-full').style.display = 'none'; document.getElementById('1409.4209v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 February, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 September, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 11 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> JOSA B, Vol. 32, Issue 4, pp. 639-648 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1409.3787">arXiv:1409.3787</a> <span> [<a href="https://arxiv.org/pdf/1409.3787">pdf</a>, <a href="https://arxiv.org/ps/1409.3787">ps</a>, <a href="https://arxiv.org/format/1409.3787">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.91.075304">10.1103/PhysRevB.91.075304 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Extended linear regime of cavity-QED enhanced optical circular birefringence induced by a charged quantum dot </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hu%2C+C+Y">C. Y. Hu</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1409.3787v2-abstract-short" style="display: inline;"> Giant optical Faraday rotation (GFR) and giant optical circular birefringence (GCB) induced by a single quantum-dot spin in an optical microcavity can be regarded as linear effects in the weak-excitation approximation if the input field lies in the low-power limit [Hu et al, Phys.Rev. B {\bf 78}, 085307(2008) and ibid {\bf 80}, 205326(2009)]. In this work, we investigate the transition from the we… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.3787v2-abstract-full').style.display = 'inline'; document.getElementById('1409.3787v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1409.3787v2-abstract-full" style="display: none;"> Giant optical Faraday rotation (GFR) and giant optical circular birefringence (GCB) induced by a single quantum-dot spin in an optical microcavity can be regarded as linear effects in the weak-excitation approximation if the input field lies in the low-power limit [Hu et al, Phys.Rev. B {\bf 78}, 085307(2008) and ibid {\bf 80}, 205326(2009)]. In this work, we investigate the transition from the weak-excitation approximation moving into the saturation regime comparing a semiclassical approximation with the numerical results from a quantum optics toolbox [S.M. Tan, J. Opt. B {\bf 1}, 424 (1999)]. We find that the GFR and GCB around the cavity resonance in the strong coupling regime are input-field independent at intermediate powers and can be well described by the semiclassical approximation. Those associated with the dressed state resonances in the strong coupling regime or merging with the cavity resonance in the Purcell regime are sensitive to input field at intermediate powers, and cannot be well described by the semiclassical approximation due to the quantum dot saturation. As the GFR and GCB around the cavity resonance are relatively immune to the saturation effects, the rapid read out of single electron spins can be carried out with coherent state and other statistically fluctuating light fields. This also shows that high speed quantum entangling gates, robust against input power variations, can be built exploiting these linear effects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.3787v2-abstract-full').style.display = 'none'; document.getElementById('1409.3787v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 January, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 September, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Section IV has been added to show the linear GFR/GCB is not affected by high-order dressed state resonances in reflection/transmission spectra. 11 pages, 9 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 91, 075304 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1406.0714">arXiv:1406.0714</a> <span> [<a href="https://arxiv.org/pdf/1406.0714">pdf</a>, <a href="https://arxiv.org/ps/1406.0714">ps</a>, <a href="https://arxiv.org/format/1406.0714">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.115.153901">10.1103/PhysRevLett.115.153901 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Polarization engineering in photonic crystal waveguides for spin-photon entanglers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Young%2C+A+B">Andrew B. Young</a>, <a href="/search/quant-ph?searchtype=author&query=Thijssen%2C+A">Arthur Thijssen</a>, <a href="/search/quant-ph?searchtype=author&query=Beggs%2C+D+M">Daryl M. Beggs</a>, <a href="/search/quant-ph?searchtype=author&query=Androvitsaneas%2C+P">Petros Androvitsaneas</a>, <a href="/search/quant-ph?searchtype=author&query=Kuipers%2C+L">L. Kuipers</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Hughes%2C+S">Stephen Hughes</a>, <a href="/search/quant-ph?searchtype=author&query=Oulton%2C+R">Ruth Oulton</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1406.0714v2-abstract-short" style="display: inline;"> By performing a full analysis of the projected local density of states (LDOS) in a photonic crystal waveguide, we show that phase plays a crucial role in the symmetry of the light-matter interaction. By considering a quantum dot (QD) spin coupled to a photonic crystal waveguide (PCW) mode, we demonstrate that the light-matter interaction can be asymmetric, leading to unidirectional emission and a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.0714v2-abstract-full').style.display = 'inline'; document.getElementById('1406.0714v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1406.0714v2-abstract-full" style="display: none;"> By performing a full analysis of the projected local density of states (LDOS) in a photonic crystal waveguide, we show that phase plays a crucial role in the symmetry of the light-matter interaction. By considering a quantum dot (QD) spin coupled to a photonic crystal waveguide (PCW) mode, we demonstrate that the light-matter interaction can be asymmetric, leading to unidirectional emission and a deterministic entangled photon source. Further we show that understanding the phase associated with both the LDOS and the QD spin is essential for a range of devices that that can be realised with a QD in a PCW. We also show how quantum entanglement can completely reverse photon propagation direction, and highlight a fundamental breakdown of the semiclassical dipole approximation for describing light-matter interactions in these spin dependent systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.0714v2-abstract-full').style.display = 'none'; document.getElementById('1406.0714v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 July, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 June, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Updated version fixes some errors. The main changes have come in the second half of the paper, with a more in depth treatment of the scattering from dipoles inside the PCW</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 115, 153901 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1404.5498">arXiv:1404.5498</a> <span> [<a href="https://arxiv.org/pdf/1404.5498">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/ncomms4658">10.1038/ncomms4658 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental demonstration of a graph state quantum error-correction code </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bell%2C+B+A">B. A. Bell</a>, <a href="/search/quant-ph?searchtype=author&query=Herrera-Mart%C3%AD%2C+D+A">D. A. Herrera-Mart铆</a>, <a href="/search/quant-ph?searchtype=author&query=Tame%2C+M+S">M. S. Tame</a>, <a href="/search/quant-ph?searchtype=author&query=Markham%2C+D">D. Markham</a>, <a href="/search/quant-ph?searchtype=author&query=Wadsworth%2C+W+J">W. J. Wadsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1404.5498v1-abstract-short" style="display: inline;"> Scalable quantum computing and communication requires the protection of quantum information from the detrimental effects of decoherence and noise. Previous work tackling this problem has relied on the original circuit model for quantum computing. However, recently a family of entangled resources known as graph states has emerged as a versatile alternative for protecting quantum information. Depend… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1404.5498v1-abstract-full').style.display = 'inline'; document.getElementById('1404.5498v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1404.5498v1-abstract-full" style="display: none;"> Scalable quantum computing and communication requires the protection of quantum information from the detrimental effects of decoherence and noise. Previous work tackling this problem has relied on the original circuit model for quantum computing. However, recently a family of entangled resources known as graph states has emerged as a versatile alternative for protecting quantum information. Depending on the graph's structure, errors can be detected and corrected in an efficient way using measurement-based techniques. In this article we report an experimental demonstration of error correction using a graph state code. We have used an all-optical setup to encode quantum information into photons representing a four-qubit graph state. We are able to reliably detect errors and correct against qubit loss. The graph we have realized is setup independent, thus it could be employed in other physical settings. Our results show that graph state codes are a promising approach for achieving scalable quantum information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1404.5498v1-abstract-full').style.display = 'none'; document.getElementById('1404.5498v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 April, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 5, 3658 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1308.3436">arXiv:1308.3436</a> <span> [<a href="https://arxiv.org/pdf/1308.3436">pdf</a>, <a href="https://arxiv.org/format/1308.3436">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.112.130501">10.1103/PhysRevLett.112.130501 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Reference frame independent quantum key distribution server with telecom tether for on-chip client </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+P">P. Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Aungskunsiri%2C+K">K. Aungskunsiri</a>, <a href="/search/quant-ph?searchtype=author&query=Mart%C3%ADn-L%C3%B3pez%2C+E">E. Mart铆n-L贸pez</a>, <a href="/search/quant-ph?searchtype=author&query=Wabnig%2C+J">J. Wabnig</a>, <a href="/search/quant-ph?searchtype=author&query=Lobino%2C+M">M. Lobino</a>, <a href="/search/quant-ph?searchtype=author&query=Nock%2C+R+W">R. W. Nock</a>, <a href="/search/quant-ph?searchtype=author&query=Munns%2C+J">J. Munns</a>, <a href="/search/quant-ph?searchtype=author&query=Bonneau%2C+D">D. Bonneau</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+P">P. Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Li%2C+H+W">H. W. Li</a>, <a href="/search/quant-ph?searchtype=author&query=Laing%2C+A">A. Laing</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Niskanen%2C+A+O">A. O. Niskanen</a>, <a href="/search/quant-ph?searchtype=author&query=Thompson%2C+M+G">M. G. Thompson</a>, <a href="/search/quant-ph?searchtype=author&query=O%27Brien%2C+J+L">J. L. O'Brien</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1308.3436v1-abstract-short" style="display: inline;"> We demonstrate a client-server quantum key distribution (QKD) scheme, with large resources such as laser and detectors situated at the server-side, which is accessible via telecom-fibre, to a client requiring only an on-chip polarisation rotator, that may be integrated into a handheld device. The detrimental effects of unstable fibre birefringence are overcome by employing the reference frame inde… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1308.3436v1-abstract-full').style.display = 'inline'; document.getElementById('1308.3436v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1308.3436v1-abstract-full" style="display: none;"> We demonstrate a client-server quantum key distribution (QKD) scheme, with large resources such as laser and detectors situated at the server-side, which is accessible via telecom-fibre, to a client requiring only an on-chip polarisation rotator, that may be integrated into a handheld device. The detrimental effects of unstable fibre birefringence are overcome by employing the reference frame independent QKD protocol for polarisation qubits in polarisation maintaining fibre, where standard QKD protocols fail, as we show for comparison. This opens the way for quantum enhanced secure communications between companies and members of the general public equipped with handheld mobile devices, via telecom-fibre tethering. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1308.3436v1-abstract-full').style.display = 'none'; document.getElementById('1308.3436v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 August, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Comments welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 112, 130501 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1308.2527">arXiv:1308.2527</a> <span> [<a href="https://arxiv.org/pdf/1308.2527">pdf</a>, <a href="https://arxiv.org/ps/1308.2527">ps</a>, <a href="https://arxiv.org/format/1308.2527">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.111.093603">10.1103/PhysRevLett.111.093603 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multi-Colour Quantum Metrology with Entangled Photons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bell%2C+B">Bryn Bell</a>, <a href="/search/quant-ph?searchtype=author&query=Kannan%2C+S">Srikanth Kannan</a>, <a href="/search/quant-ph?searchtype=author&query=McMillan%2C+A">Alex McMillan</a>, <a href="/search/quant-ph?searchtype=author&query=Clark%2C+A+S">Alex S. Clark</a>, <a href="/search/quant-ph?searchtype=author&query=Wadsworth%2C+W+J">William J. Wadsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">John G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1308.2527v1-abstract-short" style="display: inline;"> Entangled photons can be used to make measurements with an accuracy beyond that possible with classical light. While most implementations of quantum metrology have used states made up of a single colour of photons, we show that entangled states of two colours can show supersensitivity to optical phase and path-length by using a photonic crystal fibre source of photon pairs inside an interferometer… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1308.2527v1-abstract-full').style.display = 'inline'; document.getElementById('1308.2527v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1308.2527v1-abstract-full" style="display: none;"> Entangled photons can be used to make measurements with an accuracy beyond that possible with classical light. While most implementations of quantum metrology have used states made up of a single colour of photons, we show that entangled states of two colours can show supersensitivity to optical phase and path-length by using a photonic crystal fibre source of photon pairs inside an interferometer. This setup is relatively simple and robust to experimental imperfections. We demonstrate sensitivity beyond the standard quantum limit and show super-resolved interference fringes using entangled states of two, four, and six photons. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1308.2527v1-abstract-full').style.display = 'none'; document.getElementById('1308.2527v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 August, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 7 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 111, 093603 (2013) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1306.5801">arXiv:1306.5801</a> <span> [<a href="https://arxiv.org/pdf/1306.5801">pdf</a>, <a href="https://arxiv.org/ps/1306.5801">ps</a>, <a href="https://arxiv.org/format/1306.5801">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/srep02032">10.1038/srep02032 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Two-photon interference between disparate sources for quantum networking </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=McMillan%2C+A+R">A. R. McMillan</a>, <a href="/search/quant-ph?searchtype=author&query=Labont%C3%A9%2C+L">L. Labont茅</a>, <a href="/search/quant-ph?searchtype=author&query=Clark%2C+A+S">A. S. Clark</a>, <a href="/search/quant-ph?searchtype=author&query=Bell%2C+B">B. Bell</a>, <a href="/search/quant-ph?searchtype=author&query=Alibart%2C+O">O. Alibart</a>, <a href="/search/quant-ph?searchtype=author&query=Martin%2C+A">A. Martin</a>, <a href="/search/quant-ph?searchtype=author&query=Wadsworth%2C+W+J">W. J. Wadsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Tanzilli%2C+S">S. Tanzilli</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1306.5801v1-abstract-short" style="display: inline;"> Quantum networks involve entanglement sharing between multiple users. Ideally, any two users would be able to connect regardless of the type of photon source they employ, provided they fulfill the requirements for two-photon interference. From a theoretical perspective, photons coming from different origins can interfere with a perfect visibility, provided they are made indistinguishable in all de… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.5801v1-abstract-full').style.display = 'inline'; document.getElementById('1306.5801v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1306.5801v1-abstract-full" style="display: none;"> Quantum networks involve entanglement sharing between multiple users. Ideally, any two users would be able to connect regardless of the type of photon source they employ, provided they fulfill the requirements for two-photon interference. From a theoretical perspective, photons coming from different origins can interfere with a perfect visibility, provided they are made indistinguishable in all degrees of freedom. Previous experimental demonstrations of such a scenario have been limited to photon wavelengths below 900 nm, unsuitable for long distance communication, and suffered from low interference visibility. We report two-photon interference using two disparate heralded single photon sources, which involve different nonlinear effects, operating in the telecom wavelength range. The measured visibility of the two-photon interference is 80+/-4%, which paves the way to hybrid universal quantum networks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.5801v1-abstract-full').style.display = 'none'; document.getElementById('1306.5801v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 June, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Sci. Rep. 3, 2032 (2013) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1305.3357">arXiv:1305.3357</a> <span>  </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum enhanced metrology in the presence of arbitrary loss </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a>, <a href="/search/quant-ph?searchtype=author&query=Bell%2C+B">B. Bell</a>, <a href="/search/quant-ph?searchtype=author&query=Young%2C+A+B">A. B. Young</a>, <a href="/search/quant-ph?searchtype=author&query=Hu%2C+C+Y">C. Y. Hu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1305.3357v2-abstract-short" style="display: inline;"> We introduce the concept of entanglement enhanced interferometry from the viewpoint of the detected photons. The standard quantum limit is achieved when sequentially detected photons are assumed to be in an uncorrelated product state. However when we access the correlations between the detected photons that existed before the interferometer it becomes clear that entanglement enhanced measurement b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1305.3357v2-abstract-full').style.display = 'inline'; document.getElementById('1305.3357v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1305.3357v2-abstract-full" style="display: none;"> We introduce the concept of entanglement enhanced interferometry from the viewpoint of the detected photons. The standard quantum limit is achieved when sequentially detected photons are assumed to be in an uncorrelated product state. However when we access the correlations between the detected photons that existed before the interferometer it becomes clear that entanglement enhanced measurement beyond the quantum limit could be achieved independent of loss. We describe possible realisations of this post-measurement entanglement detection using a small array of spin photon entangling gates. We then describe a proof of principle experiment using only linear optics resources. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1305.3357v2-abstract-full').style.display = 'none'; document.getElementById('1305.3357v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 June, 2013; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 May, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">This paper has been withdrawn by the authors due to some crucial errors</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1305.0212">arXiv:1305.0212</a> <span> [<a href="https://arxiv.org/pdf/1305.0212">pdf</a>, <a href="https://arxiv.org/ps/1305.0212">ps</a>, <a href="https://arxiv.org/format/1305.0212">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1367-2630/15/5/053030">10.1088/1367-2630/15/5/053030 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Experimental characterization of universal one-way quantum computing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bell%2C+B+A">B. A. Bell</a>, <a href="/search/quant-ph?searchtype=author&query=Tame%2C+M+S">M. S. Tame</a>, <a href="/search/quant-ph?searchtype=author&query=Clark%2C+A+S">A. S. Clark</a>, <a href="/search/quant-ph?searchtype=author&query=Nock%2C+R+W">R. W. Nock</a>, <a href="/search/quant-ph?searchtype=author&query=Wadsworth%2C+W+J">W. J. Wadsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Rarity%2C+J+G">J. G. Rarity</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1305.0212v1-abstract-short" style="display: inline;"> We report the characterization of a universal set of logic gates for one-way quantum computing using a four-photon `star' cluster state generated by fusing photons from two independent photonic crystal fibre sources. We obtain a fidelity for the cluster state of 0.66 +/- 0.01 with respect to the ideal case. We perform quantum process tomography to completely characterize a controlled-NOT, Hadamard… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1305.0212v1-abstract-full').style.display = 'inline'; document.getElementById('1305.0212v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1305.0212v1-abstract-full" style="display: none;"> We report the characterization of a universal set of logic gates for one-way quantum computing using a four-photon `star' cluster state generated by fusing photons from two independent photonic crystal fibre sources. We obtain a fidelity for the cluster state of 0.66 +/- 0.01 with respect to the ideal case. We perform quantum process tomography to completely characterize a controlled-NOT, Hadamard and T gate all on the same compact entangled resource. Together, these operations make up a universal set of gates such that arbitrary quantum logic can be efficiently constructed from combinations of them. We find process fidelities with respect to the ideal cases of 0.64 +/- 0.01 for the CNOT, 0.67 +/- 0.03 for the Hadamard and 0.76 +/- 0.04 for the T gate. The characterisation of these gates enables the simulation of larger protocols and algorithms. As a basic example, we simulate a Swap gate consisting of three concatenated CNOT gates. Our work provides some pragmatic insights into the prospects for building up to a fully scalable and fault-tolerant one-way quantum computer with photons in realistic conditions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1305.0212v1-abstract-full').style.display = 'none'; document.getElementById('1305.0212v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 May, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 7 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> New J. Phys. 15, 053030 (2013) </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Rarity%2C+J+G&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Rarity%2C+J+G&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Rarity%2C+J+G&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div 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