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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <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/2502.01040">arXiv:2502.01040</a> <span> [<a href="https://arxiv.org/pdf/2502.01040">pdf</a>, <a href="https://arxiv.org/format/2502.01040">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Enhancement of Electric Drive in Silicon Quantum Dots with Electric Quadrupole Spin Resonance </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Mai%2C+P+Y">Philip Y. Mai</a>, <a href="/search/cond-mat?searchtype=author&query=Pereira%2C+P+H">Pedro H. Pereira</a>, <a href="/search/cond-mat?searchtype=author&query=Alonso%2C+L+A">Lucas Andrade Alonso</a>, <a href="/search/cond-mat?searchtype=author&query=Leon%2C+R+C+C">Ross C. C. Leon</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+J+C+C">Jason C. C. Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Dunmore%2C+D">Daniel Dunmore</a>, <a href="/search/cond-mat?searchtype=author&query=Lemyre%2C+J+C">Julien Camirand Lemyre</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">Wister Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">Kuan Yen Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Cifuentes%2C+J+D">Jes煤s D. Cifuentes</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Pioro-Ladri%C3%A8re%2C+M">Michel Pioro-Ladri猫re</a>, <a href="/search/cond-mat?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/cond-mat?searchtype=author&query=Souza%2C+R+d+M+e">Reinaldo de Melo e Souza</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A">Andrew Dzurak</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</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="2502.01040v2-abstract-short" style="display: inline;"> Quantum computation with electron spin qubits requires coherent and efficient manipulation of these spins, typically accomplished through the application of alternating magnetic or electric fields for electron spin resonance (ESR). In particular, electrical driving allows us to apply localized fields on the electrons, which benefits scale-up architectures. However, we have found that Electric Dipo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.01040v2-abstract-full').style.display = 'inline'; document.getElementById('2502.01040v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2502.01040v2-abstract-full" style="display: none;"> Quantum computation with electron spin qubits requires coherent and efficient manipulation of these spins, typically accomplished through the application of alternating magnetic or electric fields for electron spin resonance (ESR). In particular, electrical driving allows us to apply localized fields on the electrons, which benefits scale-up architectures. However, we have found that Electric Dipole Spin Resonance (EDSR) is insufficient for modeling the Rabi behavior in recent experimental studies. Therefore, we propose that the electron spin is being driven by a new method of electric spin qubit control which generalizes the spin dynamics by taking into account a quadrupolar contribution of the quantum dot: electric quadrupole spin resonance (EQSR). In this work, we explore the electric quadrupole driving of a quantum dot in silicon, specifically examining the cases of 5 and 13 electron occupancies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2502.01040v2-abstract-full').style.display = 'none'; document.getElementById('2502.01040v2-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2025. </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">Main: 5 pages, 4 figures Supp: 4 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.13882">arXiv:2411.13882</a> <span> [<a href="https://arxiv.org/pdf/2411.13882">pdf</a>, <a href="https://arxiv.org/format/2411.13882">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A 2x2 quantum dot array in silicon with fully tuneable pairwise interdot coupling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Youn%2C+T">Tony Youn</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+J+Y">Jonathan Yue Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/cond-mat?searchtype=author&query=Dickie%2C+A">Alexandra Dickie</a>, <a href="/search/cond-mat?searchtype=author&query=Yianni%2C+S">Steve Yianni</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Cifuentes%2C+J+D">Jes煤s D. Cifuentes</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</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="2411.13882v2-abstract-short" style="display: inline;"> Recent advances in semiconductor spin qubits have achieved linear arrays exceeding ten qubits. Moving to two-dimensional (2D) qubit arrays is a critical next step to advance towards fault-tolerant implementations, but it poses substantial fabrication challenges, particularly because enabling control of nearest-neighbor entanglement requires the incorporation of interstitial exchange gates between… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.13882v2-abstract-full').style.display = 'inline'; document.getElementById('2411.13882v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.13882v2-abstract-full" style="display: none;"> Recent advances in semiconductor spin qubits have achieved linear arrays exceeding ten qubits. Moving to two-dimensional (2D) qubit arrays is a critical next step to advance towards fault-tolerant implementations, but it poses substantial fabrication challenges, particularly because enabling control of nearest-neighbor entanglement requires the incorporation of interstitial exchange gates between quantum dots in the qubit architecture. In this work, we present a 2D array of silicon metal-oxide-semiconductor (MOS) quantum dots with tunable interdot coupling between all adjacent dots. The device is characterized at 4.2 K, where we demonstrate the formation and isolation of double-dot and triple-dot configurations. We show control of all nearest-neighbor tunnel couplings spanning up to 30 decades per volt through the interstitial exchange gates and use advanced modeling tools to estimate the exchange interactions that could be realized among qubits in this architecture. These results represent a significant step towards the development of 2D MOS quantum processors compatible with foundry manufacturing techniques. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.13882v2-abstract-full').style.display = 'none'; document.getElementById('2411.13882v2-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">9 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/2410.15590">arXiv:2410.15590</a> <span> [<a href="https://arxiv.org/pdf/2410.15590">pdf</a>, <a href="https://arxiv.org/format/2410.15590">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A 300 mm foundry silicon spin qubit unit cell exceeding 99% fidelity in all operations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Steinacker%2C+P">Paul Steinacker</a>, <a href="/search/cond-mat?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/cond-mat?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/cond-mat?searchtype=author&query=Nickl%2C+A">Andreas Nickl</a>, <a href="/search/cond-mat?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/cond-mat?searchtype=author&query=Candido%2C+M">Marco Candido</a>, <a href="/search/cond-mat?searchtype=author&query=Cifuentes%2C+J+D">Jesus D. Cifuentes</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Kubicek%2C+S">Stefan Kubicek</a>, <a href="/search/cond-mat?searchtype=author&query=Jussot%2C+J">Julien Jussot</a>, <a href="/search/cond-mat?searchtype=author&query=Canvel%2C+Y">Yann Canvel</a>, <a href="/search/cond-mat?searchtype=author&query=Beyne%2C+S">Sofie Beyne</a>, <a href="/search/cond-mat?searchtype=author&query=Shimura%2C+Y">Yosuke Shimura</a>, <a href="/search/cond-mat?searchtype=author&query=Loo%2C+R">Roger Loo</a>, <a href="/search/cond-mat?searchtype=author&query=Godfrin%2C+C">Clement Godfrin</a>, <a href="/search/cond-mat?searchtype=author&query=Raes%2C+B">Bart Raes</a>, <a href="/search/cond-mat?searchtype=author&query=Baudot%2C+S">Sylvain Baudot</a>, <a href="/search/cond-mat?searchtype=author&query=Wan%2C+D">Danny Wan</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/cond-mat?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a> , et al. (2 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="2410.15590v2-abstract-short" style="display: inline;"> Fabrication of quantum processors in advanced 300 mm wafer-scale complementary metal-oxide-semiconductor (CMOS) foundries provides a unique scaling pathway towards commercially viable quantum computing with potentially millions of qubits on a single chip. Here, we show precise qubit operation of a silicon two-qubit device made in a 300 mm semiconductor processing line. The key metrics including si… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15590v2-abstract-full').style.display = 'inline'; document.getElementById('2410.15590v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.15590v2-abstract-full" style="display: none;"> Fabrication of quantum processors in advanced 300 mm wafer-scale complementary metal-oxide-semiconductor (CMOS) foundries provides a unique scaling pathway towards commercially viable quantum computing with potentially millions of qubits on a single chip. Here, we show precise qubit operation of a silicon two-qubit device made in a 300 mm semiconductor processing line. The key metrics including single- and two-qubit control fidelities exceed 99% and state preparation and measurement fidelity exceeds 99.9%, as evidenced by gate set tomography (GST). We report coherence and lifetimes up to $T_\mathrm{2}^{\mathrm{*}} = 30.4$ $渭$s, $T_\mathrm{2}^{\mathrm{Hahn}} = 803$ $渭$s, and $T_1 = 6.3$ s. Crucially, the dominant operational errors originate from residual nuclear spin carrying isotopes, solvable with further isotopic purification, rather than charge noise arising from the dielectric environment. Our results answer the longstanding question whether the favourable properties including high-fidelity operation and long coherence times can be preserved when transitioning from a tailored academic to an industrial semiconductor fabrication technology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15590v2-abstract-full').style.display = 'none'; document.getElementById('2410.15590v2-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 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">10 pages, 4 figures, 4 extended data 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/2308.12626">arXiv:2308.12626</a> <span> [<a href="https://arxiv.org/pdf/2308.12626">pdf</a>, <a href="https://arxiv.org/format/2308.12626">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Methods for transverse and longitudinal spin-photon coupling in silicon quantum dots with intrinsic spin-orbit effect </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Guo%2C+K+S">Kevin S. Guo</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</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="2308.12626v1-abstract-short" style="display: inline;"> In a full-scale quantum computer with a fault-tolerant architecture, having scalable, long-range interaction between qubits is expected to be a highly valuable resource. One promising method of achieving this is through the light-matter interaction between spins in semiconductors and photons in superconducting cavities. This paper examines the theory of both transverse and longitudinal spin-photon… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.12626v1-abstract-full').style.display = 'inline'; document.getElementById('2308.12626v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.12626v1-abstract-full" style="display: none;"> In a full-scale quantum computer with a fault-tolerant architecture, having scalable, long-range interaction between qubits is expected to be a highly valuable resource. One promising method of achieving this is through the light-matter interaction between spins in semiconductors and photons in superconducting cavities. This paper examines the theory of both transverse and longitudinal spin-photon coupling and their applications in the silicon metal-oxide-semiconductor (SiMOS) platform. We propose a method of coupling which uses the intrinsic spin-orbit interaction arising from orbital degeneracies in SiMOS qubits. Using theoretical analysis and experimental data, we show that the strong coupling regime is achievable in the transverse scheme. We also evaluate the feasibility of a longitudinal coupling driven by an AC modulation on the qubit. These coupling methods eschew the requirement for an external micromagnet, enhancing prospects for scalability and integration into a large-scale quantum computer. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.12626v1-abstract-full').style.display = 'none'; document.getElementById('2308.12626v1-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 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.12452">arXiv:2307.12452</a> <span> [<a href="https://arxiv.org/pdf/2307.12452">pdf</a>, <a href="https://arxiv.org/format/2307.12452">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> <p class="title is-5 mathjax"> Characterizing non-Markovian Quantum Process by Fast Bayesian Tomography </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Su%2C+R+Y">R. Y. Su</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+J+Y">J. Y. Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Stuyck%2C+N+D">N. Dumoulin. Stuyck</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+M+K">M. K. Feng</a>, <a href="/search/cond-mat?searchtype=author&query=Gilbert%2C+W">W. Gilbert</a>, <a href="/search/cond-mat?searchtype=author&query=Evans%2C+T+J">T. J. Evans</a>, <a href="/search/cond-mat?searchtype=author&query=Lim%2C+W+H">W. H. Lim</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">F. E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">W. Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Harper%2C+R">R. Harper</a>, <a href="/search/cond-mat?searchtype=author&query=Bartlett%2C+S+D">S. D. Bartlett</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">C. H. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">A. Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">A. Saraiva</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">T. Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</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="2307.12452v2-abstract-short" style="display: inline;"> To push gate performance to levels beyond the thresholds for quantum error correction, it is important to characterize the error sources occurring on quantum gates. However, the characterization of non-Markovian error poses a challenge to current quantum process tomography techniques. Fast Bayesian Tomography (FBT) is a self-consistent gate set tomography protocol that can be bootstrapped from ear… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.12452v2-abstract-full').style.display = 'inline'; document.getElementById('2307.12452v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.12452v2-abstract-full" style="display: none;"> To push gate performance to levels beyond the thresholds for quantum error correction, it is important to characterize the error sources occurring on quantum gates. However, the characterization of non-Markovian error poses a challenge to current quantum process tomography techniques. Fast Bayesian Tomography (FBT) is a self-consistent gate set tomography protocol that can be bootstrapped from earlier characterization knowledge and be updated in real-time with arbitrary gate sequences. Here we demonstrate how FBT allows for the characterization of key non-Markovian error processes. We introduce two experimental protocols for FBT to diagnose the non-Markovian behavior of two-qubit systems on silicon quantum dots. To increase the efficiency and scalability of the experiment-analysis loop, we develop an online FBT software stack. To reduce experiment cost and analysis time, we also introduce a native readout method and warm boot strategy. Our results demonstrate that FBT is a useful tool for probing non-Markovian errors that can be detrimental to the ultimate realization of fault-tolerant operation on quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.12452v2-abstract-full').style.display = 'none'; document.getElementById('2307.12452v2-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.01065">arXiv:2212.01065</a> <span> [<a href="https://arxiv.org/pdf/2212.01065">pdf</a>, <a href="https://arxiv.org/format/2212.01065">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="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-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/10.1063/5.0129345">10.1063/5.0129345 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Initial experimental results on a superconducting-qubit reset based on photon-assisted quasiparticle tunneling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sevriuk%2C+V+A">V. A. Sevriuk</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+W">W. Liu</a>, <a href="/search/cond-mat?searchtype=author&query=R%C3%B6nkk%C3%B6%2C+J">J. R枚nkk枚</a>, <a href="/search/cond-mat?searchtype=author&query=Hsu%2C+H">H. Hsu</a>, <a href="/search/cond-mat?searchtype=author&query=Marxer%2C+F">F. Marxer</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%B6rstedt%2C+T+F">T. F. M枚rstedt</a>, <a href="/search/cond-mat?searchtype=author&query=Partanen%2C+M">M. Partanen</a>, <a href="/search/cond-mat?searchtype=author&query=R%C3%A4bin%C3%A4%2C+J">J. R盲bin盲</a>, <a href="/search/cond-mat?searchtype=author&query=Venkatesh%2C+M">M. Venkatesh</a>, <a href="/search/cond-mat?searchtype=author&query=Hotari%2C+J">J. Hotari</a>, <a href="/search/cond-mat?searchtype=author&query=Gr%C3%B6nberg%2C+L">L. Gr枚nberg</a>, <a href="/search/cond-mat?searchtype=author&query=Heinsoo%2C+J">J. Heinsoo</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+T">T. Li</a>, <a href="/search/cond-mat?searchtype=author&query=Tuorila%2C+J">J. Tuorila</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Hassel%2C+J">J. Hassel</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">K. Y. Tan</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%B6tt%C3%B6nen%2C+M">M. M枚tt枚nen</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="2212.01065v1-abstract-short" style="display: inline;"> We present here our recent results on qubit reset scheme based on a quantum-circuit refrigerator (QCR). In particular, we use the photon-assisted quasiparticle tunneling through a superconductor--insulator--normal-metal--insulator--superconductor junction to controllably decrease the energy relaxation time of the qubit during the QCR operation. In our experiment, we use a transmon qubit with dispe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.01065v1-abstract-full').style.display = 'inline'; document.getElementById('2212.01065v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.01065v1-abstract-full" style="display: none;"> We present here our recent results on qubit reset scheme based on a quantum-circuit refrigerator (QCR). In particular, we use the photon-assisted quasiparticle tunneling through a superconductor--insulator--normal-metal--insulator--superconductor junction to controllably decrease the energy relaxation time of the qubit during the QCR operation. In our experiment, we use a transmon qubit with dispersive readout. The QCR is capacitively coupled to the qubit through its normal-metal island. We employ rapid, square-shaped QCR control voltage pulses with durations in the range of 2--350 ns and a variety of amplitudes to optimize the reset time and fidelity. Consequently, we reach a qubit ground-state probability of roughly 97% with 80-ns pulses starting from the first excited state. The qubit state probability is extracted from averaged readout signal, where the calibration is based of the Rabi oscillations, thus not distinguishing the residual thermal population of the qubit. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.01065v1-abstract-full').style.display = 'none'; document.getElementById('2212.01065v1-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 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> Appl. Phys. Lett. 121, 234002 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.11865">arXiv:2207.11865</a> <span> [<a href="https://arxiv.org/pdf/2207.11865">pdf</a>, <a href="https://arxiv.org/format/2207.11865">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="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/PhysRevB.107.085427">10.1103/PhysRevB.107.085427 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Control of dephasing in spin qubits during coherent transport in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/cond-mat?searchtype=author&query=Yoneda%2C+J">Jun Yoneda</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">Wister Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Su%2C+Y">Yue Su</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Cifuentes%2C+J+D">Jesus D. Cifuentes</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Gilbert%2C+W">William Gilbert</a>, <a href="/search/cond-mat?searchtype=author&query=Leon%2C+R+C+C">Ross C. C. Leon</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</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="2207.11865v2-abstract-short" style="display: inline;"> One of the key pathways towards scalability of spin-based quantum computing systems lies in achieving long-range interactions between electrons and increasing their inter-connectivity. Coherent spin transport is one of the most promising strategies to achieve this architectural advantage. Experimental results have previously demonstrated high fidelity transportation of spin qubits between two quan… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.11865v2-abstract-full').style.display = 'inline'; document.getElementById('2207.11865v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.11865v2-abstract-full" style="display: none;"> One of the key pathways towards scalability of spin-based quantum computing systems lies in achieving long-range interactions between electrons and increasing their inter-connectivity. Coherent spin transport is one of the most promising strategies to achieve this architectural advantage. Experimental results have previously demonstrated high fidelity transportation of spin qubits between two quantum dots in silicon and identified possible sources of error. In this theoretical study, we investigate these errors and analyze the impact of tunnel coupling, magnetic field and spin-orbit effects on the spin transfer process. The interplay between these effects gives rise to double dot configurations that include regimes of enhanced decoherence that should be avoided for quantum information processing. These conclusions permit us to extrapolate previous experimental conclusions and rationalize the future design of large scale quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.11865v2-abstract-full').style.display = 'none'; document.getElementById('2207.11865v2-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 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 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">18 pages, 9 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/2108.00836">arXiv:2108.00836</a> <span> [<a href="https://arxiv.org/pdf/2108.00836">pdf</a>, <a href="https://arxiv.org/format/2108.00836">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="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/10.1063/5.0096467">10.1063/5.0096467 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Implementation of the SMART protocol for global qubit control in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Hansen%2C+I">Ingvild Hansen</a>, <a href="/search/cond-mat?searchtype=author&query=Seedhouse%2C+A+E">Amanda E. Seedhouse</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F">Fay Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</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="2108.00836v3-abstract-short" style="display: inline;"> Quantum computing based on spins in the solid state allows for densely-packed arrays of quantum bits. While high-fidelity operation of single qubits has been demonstrated with individual control pulses, the operation of large-scale quantum processors requires a shift in paradigm towards global control solutions. Here we report the experimental implementation of a new type of qubit protocol - the S… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.00836v3-abstract-full').style.display = 'inline'; document.getElementById('2108.00836v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.00836v3-abstract-full" style="display: none;"> Quantum computing based on spins in the solid state allows for densely-packed arrays of quantum bits. While high-fidelity operation of single qubits has been demonstrated with individual control pulses, the operation of large-scale quantum processors requires a shift in paradigm towards global control solutions. Here we report the experimental implementation of a new type of qubit protocol - the SMART (Sinusoidally Modulated, Always Rotating and Tailored) protocol. As with a dressed qubit, we resonantly drive a two-level system with a continuous microwave field, but here we add a tailored modulation to the dressing field to achieve increased robustness to detuning noise and microwave amplitude fluctuations. We implement this new protocol to control a single spin confined in a silicon quantum dot and confirm the optimal modulation conditions predicted from theory. Universal control of a single qubit is demonstrated using modulated Stark shift control via the local gate electrodes. We measure an extended coherence time of $2$ ms and an average Clifford gate fidelity $>99$ $\%$ despite the relatively long qubit gate times ($>15$ $\unicode[serif]{x03BC}$s, $20$ times longer than a conventional square pulse gate), constituting a significant improvement over a conventional spin qubit and a dressed qubit. This work shows that future scalable spin qubit arrays could be operated using global microwave control and local gate addressability, while maintaining robustness to relevant experimental inhomogeneities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.00836v3-abstract-full').style.display = 'none'; document.getElementById('2108.00836v3-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 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Applied Physics Reviews 9, 031409 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2008.04020">arXiv:2008.04020</a> <span> [<a href="https://arxiv.org/pdf/2008.04020">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="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/s41467-021-24371-7">10.1038/s41467-021-24371-7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coherent spin qubit transport in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yoneda%2C+J">J. Yoneda</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">W. Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Feng%2C+M">M. Feng</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">C. H. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">T. Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Gilbert%2C+W">W. Gilbert</a>, <a href="/search/cond-mat?searchtype=author&query=Leon%2C+R+C+C">R. C. C. Leon</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">F. E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">K. M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">A. Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Bartlett%2C+S+D">S. D. Bartlett</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">A. Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">A. Saraiva</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</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="2008.04020v2-abstract-short" style="display: inline;"> A fault-tolerant quantum processor may be configured using stationary qubits interacting only with their nearest neighbours, but at the cost of significant overheads in physical qubits per logical qubit. Such overheads could be reduced by coherently transporting qubits across the chip, allowing connectivity beyond immediate neighbours. Here we demonstrate high-fidelity coherent transport of an ele… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.04020v2-abstract-full').style.display = 'inline'; document.getElementById('2008.04020v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2008.04020v2-abstract-full" style="display: none;"> A fault-tolerant quantum processor may be configured using stationary qubits interacting only with their nearest neighbours, but at the cost of significant overheads in physical qubits per logical qubit. Such overheads could be reduced by coherently transporting qubits across the chip, allowing connectivity beyond immediate neighbours. Here we demonstrate high-fidelity coherent transport of an electron spin qubit between quantum dots in isotopically-enriched silicon. We observe qubit precession in the inter-site tunnelling regime and assess the impact of qubit transport using Ramsey interferometry and quantum state tomography techniques. We report a polarization transfer fidelity of 99.97% and an average coherent transfer fidelity of 99.4%. Our results provide key elements for high-fidelity, on-chip quantum information distribution, as long envisaged, reinforcing the scaling prospects of silicon-based spin qubits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.04020v2-abstract-full').style.display = 'none'; document.getElementById('2008.04020v2-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 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 August, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 12, 4114 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.07666">arXiv:2004.07666</a> <span> [<a href="https://arxiv.org/pdf/2004.07666">pdf</a>, <a href="https://arxiv.org/format/2004.07666">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/10.1021/acs.nanolett.0c04771">10.1021/acs.nanolett.0c04771 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Exchange coupling in a linear chain of three quantum-dot spin qubits in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Sahasrabudhe%2C+H">Harshad Sahasrabudhe</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">Wister Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y">Yu Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+H+C">Henry C. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Veldhorst%2C+M">Menno Veldhorst</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+J+C+C">Jason C. C. Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Mohiyaddin%2C+F+A">Fahd A. Mohiyaddin</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">Andrea Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Rahman%2C+R">Rajib Rahman</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</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="2004.07666v1-abstract-short" style="display: inline;"> Quantum gates between spin qubits can be implemented leveraging the natural Heisenberg exchange interaction between two electrons in contact with each other. This interaction is controllable by electrically tailoring the overlap between electronic wavefunctions in quantum dot systems, as long as they occupy neighbouring dots. An alternative route is the exploration of superexchange - the coupling… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.07666v1-abstract-full').style.display = 'inline'; document.getElementById('2004.07666v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.07666v1-abstract-full" style="display: none;"> Quantum gates between spin qubits can be implemented leveraging the natural Heisenberg exchange interaction between two electrons in contact with each other. This interaction is controllable by electrically tailoring the overlap between electronic wavefunctions in quantum dot systems, as long as they occupy neighbouring dots. An alternative route is the exploration of superexchange - the coupling between remote spins mediated by a third idle electron that bridges the distance between quantum dots. We experimentally demonstrate direct exchange coupling and provide evidence for second neighbour mediated superexchange in a linear array of three single-electron spin qubits in silicon, inferred from the electron spin resonance frequency spectra. We confirm theoretically through atomistic modeling that the device geometry only allows for sizeable direct exchange coupling for neighbouring dots, while next nearest neighbour coupling cannot stem from the vanishingly small tail of the electronic wavefunction of the remote dots, and is only possible if mediated. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.07666v1-abstract-full').style.display = 'none'; document.getElementById('2004.07666v1-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 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">20 pages, 1.4MB, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nano Letters 2021, 21, 3, 1517-1522 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1911.10709">arXiv:1911.10709</a> <span> [<a href="https://arxiv.org/pdf/1911.10709">pdf</a>, <a href="https://arxiv.org/format/1911.10709">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/PhysRevApplied.13.054005">10.1103/PhysRevApplied.13.054005 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Autonomous tuning and charge state detection of gate defined quantum dots </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Darulov%C3%A1%2C+J">J. Darulov谩</a>, <a href="/search/cond-mat?searchtype=author&query=Pauka%2C+S+J">S. J. Pauka</a>, <a href="/search/cond-mat?searchtype=author&query=Wiebe%2C+N">N. Wiebe</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Gardener%2C+G+C">G. C. Gardener</a>, <a href="/search/cond-mat?searchtype=author&query=Manfra%2C+M+J">M. J. Manfra</a>, <a href="/search/cond-mat?searchtype=author&query=Cassidy%2C+M+C">M. C. Cassidy</a>, <a href="/search/cond-mat?searchtype=author&query=Troyer%2C+M">M. Troyer</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="1911.10709v2-abstract-short" style="display: inline;"> Defining quantum dots in semiconductor based heterostructures is an essential step in initializing solid-state qubits. With growing device complexity and increasing number of functional devices required for measurements, a manual approach to finding suitable gate voltages to confine electrons electrostatically is impractical. Here, we implement a two-stage device characterization and dot-tuning pr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.10709v2-abstract-full').style.display = 'inline'; document.getElementById('1911.10709v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1911.10709v2-abstract-full" style="display: none;"> Defining quantum dots in semiconductor based heterostructures is an essential step in initializing solid-state qubits. With growing device complexity and increasing number of functional devices required for measurements, a manual approach to finding suitable gate voltages to confine electrons electrostatically is impractical. Here, we implement a two-stage device characterization and dot-tuning process which first determines whether devices are functional and then attempts to tune the functional devices to the single or double quantum dot regime. We show that automating well established manual tuning procedures and replacing the experimenter's decisions by supervised machine learning is sufficient to tune double quantum dots in multiple devices without pre-measured input or manual intervention. The quality of measurement results and charge states are assessed by four binary classifiers trained with experimental data, reflecting real device behaviour. We compare and optimize eight models and different data preprocessing techniques for each of the classifiers to achieve reliable autonomous tuning, an essential step towards scalable quantum systems in quantum dot based qubit architectures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.10709v2-abstract-full').style.display = 'none'; document.getElementById('1911.10709v2-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 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 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> Phys. Rev. Applied 13, 054005 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1909.11976">arXiv:1909.11976</a> <span> [<a href="https://arxiv.org/pdf/1909.11976">pdf</a>, <a href="https://arxiv.org/format/1909.11976">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Superconducting charge sensor coupled to an electron layer in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Jenei%2C+M">M谩t茅 Jenei</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+R">Ruichen Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">Kuan Y. Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Sun%2C+Y">Yuxin Sun</a>, <a href="/search/cond-mat?searchtype=author&query=Sevriuk%2C+V">Vasilii Sevriuk</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F">Fay Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Rossi%2C+A">Alessandro Rossi</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A">Andrew Dzurak</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%B6tt%C3%B6nen%2C+M">Mikko M枚tt枚nen</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="1909.11976v1-abstract-short" style="display: inline;"> Schemes aimed at transferring individual electrons in semiconductor devices and detecting possible transfer errors have increasing importance for metrological applications. We study the coupling of a superconducting Josephson-junction-based charge detector to an electron island defined by field-effect in silicon. The flexibility of our device allows one to tune the coupling using the detector as a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.11976v1-abstract-full').style.display = 'inline'; document.getElementById('1909.11976v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.11976v1-abstract-full" style="display: none;"> Schemes aimed at transferring individual electrons in semiconductor devices and detecting possible transfer errors have increasing importance for metrological applications. We study the coupling of a superconducting Josephson-junction-based charge detector to an electron island defined by field-effect in silicon. The flexibility of our device allows one to tune the coupling using the detector as an additional gate electrode. We study the reliability of the electron sensor in different device configurations and the suitability of various operation modes for error detection in electron pumping experiments. As a result, we obtain a charge detection bandwidth of 5.87 kHz with unity signal to noise ratio at 300 mK bath temperature. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.11976v1-abstract-full').style.display = 'none'; document.getElementById('1909.11976v1-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 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">7 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/1909.02866">arXiv:1909.02866</a> <span> [<a href="https://arxiv.org/pdf/1909.02866">pdf</a>, <a href="https://arxiv.org/format/1909.02866">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="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/PhysRevResearch.1.033163">10.1103/PhysRevResearch.1.033163 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Waiting time distributions in a two-level fluctuator coupled to a superconducting charge detector </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Jenei%2C+M">M谩t茅 Jenei</a>, <a href="/search/cond-mat?searchtype=author&query=Potanina%2C+E">Elina Potanina</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+R">Ruichen Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">Kuan Y. Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Rossi%2C+A">Alessandro Rossi</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Sevriuk%2C+V">Vasilii Sevriuk</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%B6tt%C3%B6nen%2C+M">Mikko M枚tt枚nen</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A">Andrew Dzurak</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="1909.02866v2-abstract-short" style="display: inline;"> We analyze charge fluctuations in a parasitic state strongly coupled to a superconducting Josephson-junction-based charge detector. The charge dynamics of the state resembles that of electron transport in a quantum dot with two charge states, and hence we refer to it as a two-level fluctuator. By constructing the distribution of waiting times from the measured detector signal and comparing it with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.02866v2-abstract-full').style.display = 'inline'; document.getElementById('1909.02866v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.02866v2-abstract-full" style="display: none;"> We analyze charge fluctuations in a parasitic state strongly coupled to a superconducting Josephson-junction-based charge detector. The charge dynamics of the state resembles that of electron transport in a quantum dot with two charge states, and hence we refer to it as a two-level fluctuator. By constructing the distribution of waiting times from the measured detector signal and comparing it with a waiting time theory, we extract the electron in- and out-tunneling rates for the two-level fluctuator, which are severely asymmetric. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.02866v2-abstract-full').style.display = 'none'; document.getElementById('1909.02866v2-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 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 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">7 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. Research 1, 033163 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1902.09126">arXiv:1902.09126</a> <span> [<a href="https://arxiv.org/pdf/1902.09126">pdf</a>, <a href="https://arxiv.org/format/1902.09126">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="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/s41586-020-2171-6">10.1038/s41586-020-2171-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Silicon quantum processor unit cell operation above one Kelvin </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">C. H. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Leon%2C+R+C+C">R. C. C. Leon</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+J+C+C">J. C. C. Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">A. Saraiva</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">T. Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">W. Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Lemyre%2C+J+C">J. Camirand Lemyre</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">K. Y. Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">F. E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">K. M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">A. Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Pioro-Ladri%C3%A8re%2C+M">M. Pioro-Ladri猫re</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">A. Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</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="1902.09126v2-abstract-short" style="display: inline;"> Quantum computers are expected to outperform conventional computers for a range of important problems, from molecular simulation to search algorithms, once they can be scaled up to large numbers of quantum bits (qubits), typically millions. For most solid-state qubit technologies, e.g. those using superconducting circuits or semiconductor spins, scaling poses a significant challenge as every addit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.09126v2-abstract-full').style.display = 'inline'; document.getElementById('1902.09126v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1902.09126v2-abstract-full" style="display: none;"> Quantum computers are expected to outperform conventional computers for a range of important problems, from molecular simulation to search algorithms, once they can be scaled up to large numbers of quantum bits (qubits), typically millions. For most solid-state qubit technologies, e.g. those using superconducting circuits or semiconductor spins, scaling poses a significant challenge as every additional qubit increases the heat generated, while the cooling power of dilution refrigerators is severely limited at their operating temperature below 100 mK. Here we demonstrate operation of a scalable silicon quantum processor unit cell, comprising two qubits confined to quantum dots (QDs) at $\sim$1.5 Kelvin. We achieve this by isolating the QDs from the electron reservoir, initialising and reading the qubits solely via tunnelling of electrons between the two QDs. We coherently control the qubits using electrically-driven spin resonance (EDSR) in isotopically enriched silicon $^{28}$Si, attaining single-qubit gate fidelities of 98.6% and coherence time $T_2^*$ = 2$渭$s during `hot' operation, comparable to those of spin qubits in natural silicon at millikelvin temperatures. Furthermore, we show that the unit cell can be operated at magnetic fields as low as 0.1 T, corresponding to a qubit control frequency of 3.5 GHz, where the qubit energy is well below the thermal energy. The unit cell constitutes the core building block of a full-scale silicon quantum computer, and satisfies layout constraints required by error correction architectures. Our work indicates that a spin-based quantum computer could be operated at elevated temperatures in a simple pumped $^4$He system, offering orders of magnitude higher cooling power than dilution refrigerators, potentially enabling classical control electronics to be integrated with the qubit array. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.09126v2-abstract-full').style.display = 'none'; document.getElementById('1902.09126v2-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 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 February, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 580, 350-354 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1902.01550">arXiv:1902.01550</a> <span> [<a href="https://arxiv.org/pdf/1902.01550">pdf</a>, <a href="https://arxiv.org/format/1902.01550">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1038/s41467-019-14053-w">10.1038/s41467-019-14053-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coherent spin control of s-, p-, d- and f-electrons in a silicon quantum dot </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Leon%2C+R+C+C">R. C. C. Leon</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">C. H. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+J+C+C">J. C. C. Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Lemyre%2C+J+C">J. Camirand Lemyre</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">T. Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">W. Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">K. Y. Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">F. E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">K. M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">A. Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">A. Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Pioro-Ladriere%2C+M">M. Pioro-Ladriere</a>, <a href="/search/cond-mat?searchtype=author&query=Saraiva%2C+A">A. Saraiva</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</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="1902.01550v3-abstract-short" style="display: inline;"> Once the periodic properties of elements were unveiled, chemical bonds could be understood in terms of the valence of atoms. Ideally, this rationale would extend to quantum dots, often termed artificial atoms, and quantum computation could be performed by merely controlling the outer-shell electrons of dot-based qubits. Imperfections in the semiconductor material, including at the atomic scale, di… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.01550v3-abstract-full').style.display = 'inline'; document.getElementById('1902.01550v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1902.01550v3-abstract-full" style="display: none;"> Once the periodic properties of elements were unveiled, chemical bonds could be understood in terms of the valence of atoms. Ideally, this rationale would extend to quantum dots, often termed artificial atoms, and quantum computation could be performed by merely controlling the outer-shell electrons of dot-based qubits. Imperfections in the semiconductor material, including at the atomic scale, disrupt this analogy between atoms and quantum dots, so that real devices seldom display such a systematic many-electron arrangement. We demonstrate here an electrostatically-defined quantum dot that is robust to disorder, revealing a well defined shell structure. We observe four shells (31 electrons) with multiplicities given by spin and valley degrees of freedom. We explore various fillings consisting of a single valence electron -- namely 1, 5, 13 and 25 electrons -- as potential qubits, and we identify fillings that yield a total spin-1 on the dot. An integrated micromagnet allows us to perform electrically-driven spin resonance (EDSR). Higher shell states are shown to be more susceptible to the driving field, leading to faster Rabi rotations of the qubit. We investigate the impact of orbital excitations of the p- and d-shell electrons on single qubits as a function of the dot deformation. This allows us to tune the dot excitation spectrum and exploit it for faster qubit control. Furthermore, hotspots arising from this tunable energy level structure provide a pathway towards fast spin initialisation. The observation of spin-1 states may be exploited in the future to study symmetry-protected topological states in antiferromagnetic spin chains and their application to quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.01550v3-abstract-full').style.display = 'none'; document.getElementById('1902.01550v3-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> 6 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 February, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 11, 797 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1812.08347">arXiv:1812.08347</a> <span> [<a href="https://arxiv.org/pdf/1812.08347">pdf</a>, <a href="https://arxiv.org/format/1812.08347">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1038/s41467-019-13416-7">10.1038/s41467-019-13416-7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Single-spin qubits in isotopically enriched silicon at low magnetic field </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+R">R. Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">T. Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">K. Y. Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Hensen%2C+B">B. Hensen</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+J+C+C">J. C. C. Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Leon%2C+R+C+C">R. C. C. Leon</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">C. H. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Gilbert%2C+W">W. Gilbert</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">F. E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">K. M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Kiselev%2C+A+A">A. A. Kiselev</a>, <a href="/search/cond-mat?searchtype=author&query=Ladd%2C+T+D">T. D. Ladd</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">A. Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">A. Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</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="1812.08347v5-abstract-short" style="display: inline;"> Single-electron spin qubits employ magnetic fields on the order of 1 Tesla or above to enable quantum state readout via spin-dependent-tunnelling. This requires demanding microwave engineering for coherent spin resonance control and significant on-chip real estate for electron reservoirs, both of which limit the prospects for large scale multi-qubit systems. Alternatively, singlet-triplet (ST) rea… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.08347v5-abstract-full').style.display = 'inline'; document.getElementById('1812.08347v5-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1812.08347v5-abstract-full" style="display: none;"> Single-electron spin qubits employ magnetic fields on the order of 1 Tesla or above to enable quantum state readout via spin-dependent-tunnelling. This requires demanding microwave engineering for coherent spin resonance control and significant on-chip real estate for electron reservoirs, both of which limit the prospects for large scale multi-qubit systems. Alternatively, singlet-triplet (ST) readout enables high-fidelity spin-state measurements in much lower magnetic fields, without the need for reservoirs. Here, we demonstrate low-field operation of metal-oxide-silicon (MOS) quantum dot qubits by combining coherent single-spin control with high-fidelity, single-shot, Pauli-spin-blockade-based ST readout. We discover that the qubits decohere faster at low magnetic fields with $T_{2}^{Rabi}=18.6$~$渭$s and $T_2^*=1.4$~$渭$s at 150~mT. Their coherence is limited by spin flips of residual $^{29}$Si nuclei in the isotopically enriched $^{28}$Si host material, which occur more frequently at lower fields. Our finding indicates that new trade-offs will be required to ensure the frequency stabilization of spin qubits and highlights the importance of isotopic enrichment of device substrates for the realization of a scalable silicon-based quantum processor. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.08347v5-abstract-full').style.display = 'none'; document.getElementById('1812.08347v5-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 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 December, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat Commun 10, 5500 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.10415">arXiv:1807.10415</a> <span> [<a href="https://arxiv.org/pdf/1807.10415">pdf</a>, <a href="https://arxiv.org/ps/1807.10415">ps</a>, <a href="https://arxiv.org/format/1807.10415">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/PhysRevX.9.021028">10.1103/PhysRevX.9.021028 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Controlling spin-orbit interactions in silicon quantum dots using magnetic field direction </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Hensen%2C+B">Bas Hensen</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+H">Henry Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">Wister Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Fogarty%2C+M">Michael Fogarty</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F">Fay Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K">Kohei Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Culcer%2C+D">Dimitrie Culcer</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">Andrea Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A">Andrew Dzurak</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="1807.10415v4-abstract-short" style="display: inline;"> Silicon quantum dots are considered an excellent platform for spin qubits, partly due to their weak spin-orbit interaction. However, the sharp interfaces in the heterostructures induce a small but significant spin-orbit interaction which degrade the performance of the qubits or, when understood and controlled, could be used as a powerful resource. To understand how to control this interaction we b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.10415v4-abstract-full').style.display = 'inline'; document.getElementById('1807.10415v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.10415v4-abstract-full" style="display: none;"> Silicon quantum dots are considered an excellent platform for spin qubits, partly due to their weak spin-orbit interaction. However, the sharp interfaces in the heterostructures induce a small but significant spin-orbit interaction which degrade the performance of the qubits or, when understood and controlled, could be used as a powerful resource. To understand how to control this interaction we build a detailed profile of the spin-orbit interaction of a silicon metal-oxide-semiconductor double quantum dot system. We probe the derivative of the Stark shift, $g$-factor and $g$-factor difference for two single-electron quantum dot qubits as a function of external magnetic field and find that they are dominated by spin-orbit interactions originating from the vector potential, consistent with recent theoretical predictions. Conversely, by populating the double dot with two electrons we probe the mixing of singlet and spin-polarized triplet states during electron tunneling, which we conclude is dominated by momentum-term spin-orbit interactions that varies from 1.85 MHz up to 27.5 MHz depending on the magnetic field orientation. Finally, we exploit the tunability of the derivative of the Stark shift of one of the dots to reduce its sensitivity to electric noise and observe an 80 % increase in $T_2^*$. We conclude that the tuning of the spin-orbit interaction will be crucial for scalable quantum computing in silicon and that the optimal setting will depend on the exact mode of qubit operations used. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.10415v4-abstract-full').style.display = 'none'; document.getElementById('1807.10415v4-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, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 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">Journal ref:</span> Phys. Rev. X 9, 021028 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.09500">arXiv:1807.09500</a> <span> [<a href="https://arxiv.org/pdf/1807.09500">pdf</a>, <a href="https://arxiv.org/format/1807.09500">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="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/s41928-019-0234-1">10.1038/s41928-019-0234-1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Silicon qubit fidelities approaching incoherent noise limits via pulse engineering </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">C. H. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Harper%2C+R">R. Harper</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">W. Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Evans%2C+T">T. Evans</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+J+C+C">J. C. C. Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Hensen%2C+B">B. Hensen</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">A. Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">T. Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">F. E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Flammia%2C+S+T">S. T. Flammia</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">K. M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">A. Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Bartlett%2C+S+D">S. D. Bartlett</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</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="1807.09500v3-abstract-short" style="display: inline;"> The performance requirements for fault-tolerant quantum computing are very stringent. Qubits must be manipulated, coupled, and measured with error rates well below 1%. For semiconductor implementations, silicon quantum dot spin qubits have demonstrated average single-qubit Clifford gate error rates that approach this threshold, notably with error rates of 0.14% in isotopically enriched $^{28}$Si/S… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.09500v3-abstract-full').style.display = 'inline'; document.getElementById('1807.09500v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.09500v3-abstract-full" style="display: none;"> The performance requirements for fault-tolerant quantum computing are very stringent. Qubits must be manipulated, coupled, and measured with error rates well below 1%. For semiconductor implementations, silicon quantum dot spin qubits have demonstrated average single-qubit Clifford gate error rates that approach this threshold, notably with error rates of 0.14% in isotopically enriched $^{28}$Si/SiGe devices. This gate performance, together with high-fidelity two-qubit gates and measurements, is only known to meet the threshold for fault-tolerant quantum computing in some architectures when assuming that the noise is incoherent, and still lower error rates are needed to reduce overhead. Here we experimentally show that pulse engineering techniques, widely used in magnetic resonance, improve average Clifford gate error rates for silicon quantum dot spin qubits to 0.043%,a factor of 3 improvement on previous best results for silicon quantum dot devices. By including tomographically complete measurements in randomised benchmarking, we infer a higher-order feature of the noise called the unitarity, which measures the coherence of noise. This in turn allows us to theoretically predict that average gate error rates as low as 0.026% may be achievable with further pulse improvements. These fidelities are ultimately limited by Markovian noise, which we attribute to charge noise emanating from the silicon device structure itself, or the environment. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.09500v3-abstract-full').style.display = 'none'; document.getElementById('1807.09500v3-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 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 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">Journal ref:</span> Nature Electronics 2, 151-158 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1805.05027">arXiv:1805.05027</a> <span> [<a href="https://arxiv.org/pdf/1805.05027">pdf</a>, <a href="https://arxiv.org/format/1805.05027">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="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/s41586-019-1197-0">10.1038/s41586-019-1197-0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Fidelity benchmarks for two-qubit gates in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Huang%2C+W">W. Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C+H">C. H. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">T. Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Hensen%2C+B">B. Hensen</a>, <a href="/search/cond-mat?searchtype=author&query=Leon%2C+R+C+C">R. C. C. Leon</a>, <a href="/search/cond-mat?searchtype=author&query=Fogarty%2C+M+A">M. A. Fogarty</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+J+C+C">J. C. C. Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Hudson%2C+F+E">F. E. Hudson</a>, <a href="/search/cond-mat?searchtype=author&query=Itoh%2C+K+M">K. M. Itoh</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">A. Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Laucht%2C+A">A. Laucht</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</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="1805.05027v3-abstract-short" style="display: inline;"> Universal quantum computation will require qubit technology based on a scalable platform, together with quantum error correction protocols that place strict limits on the maximum infidelities for one- and two-qubit gate operations. While a variety of qubit systems have shown high fidelities at the one-qubit level, superconductor technologies have been the only solid-state qubits manufactured via s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.05027v3-abstract-full').style.display = 'inline'; document.getElementById('1805.05027v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1805.05027v3-abstract-full" style="display: none;"> Universal quantum computation will require qubit technology based on a scalable platform, together with quantum error correction protocols that place strict limits on the maximum infidelities for one- and two-qubit gate operations. While a variety of qubit systems have shown high fidelities at the one-qubit level, superconductor technologies have been the only solid-state qubits manufactured via standard lithographic techniques which have demonstrated two-qubit fidelities near the fault-tolerant threshold. Silicon-based quantum dot qubits are also amenable to large-scale manufacture and can achieve high single-qubit gate fidelities (exceeding 99.9%) using isotopically enriched silicon. However, while two-qubit gates have been demonstrated in silicon, it has not yet been possible to rigorously assess their fidelities using randomized benchmarking, since this requires sequences of significant numbers of qubit operations ($\gtrsim 20$) to be completed with non-vanishing fidelity. Here, for qubits encoded on the electron spin states of gate-defined quantum dots, we demonstrate Bell state tomography with fidelities ranging from 80% to 89%, and two-qubit randomized benchmarking with an average Clifford gate fidelity of 94.7% and average Controlled-ROT (CROT) fidelity of 98.0%. These fidelities are found to be limited by the relatively slow gate times employed here compared with the decoherence times $T_2^*$ of the qubits. Silicon qubit designs employing fast gate operations based on high Rabi frequencies, together with advanced pulsing techniques, should therefore enable significantly higher fidelities in the near future. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.05027v3-abstract-full').style.display = 'none'; document.getElementById('1805.05027v3-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 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 May, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 569, 532-536 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1603.01225">arXiv:1603.01225</a> <span> [<a href="https://arxiv.org/pdf/1603.01225">pdf</a>, <a href="https://arxiv.org/ps/1603.01225">ps</a>, <a href="https://arxiv.org/format/1603.01225">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Other Condensed Matter">cond-mat.other</span> </div> </div> <p class="title is-5 mathjax"> Three-waveform bidirectional pumping of single electrons with a silicon quantum dot </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Rossi%2C+A">Alessandro Rossi</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">Kuan Yen Tan</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%A4kinen%2C+A">Akseli M盲kinen</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%B6tt%C3%B6nen%2C+M">Mikko M枚tt枚nen</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="1603.01225v2-abstract-short" style="display: inline;"> Semiconductor-based quantum dot single-electron pumps are currently the most promising candidates for the direct realization of the emerging quantum standard of the ampere in the International System of Units. Here, we discuss a silicon quantum dot single-electron pump with radio frequency control over the transparencies of entrance and exit barriers as well as the dot potential. We show that our… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.01225v2-abstract-full').style.display = 'inline'; document.getElementById('1603.01225v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1603.01225v2-abstract-full" style="display: none;"> Semiconductor-based quantum dot single-electron pumps are currently the most promising candidates for the direct realization of the emerging quantum standard of the ampere in the International System of Units. Here, we discuss a silicon quantum dot single-electron pump with radio frequency control over the transparencies of entrance and exit barriers as well as the dot potential. We show that our driving protocol leads to robust bidirectional pumping: one can conveniently reverse the direction of the quantized current by changing only the phase shift of one driving waveform with respect to the others. We also study the improvement in the robustness of the current quantization owing to the introduction of three control voltages in comparison with the two-waveform driving. We anticipate that this pumping technique may be used in the future to perform error counting experiments by pumping the electrons into and out of a reservoir island monitored by a charge sensor. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.01225v2-abstract-full').style.display = 'none'; document.getElementById('1603.01225v2-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 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 March, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">9 pages, 3 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/1502.04446">arXiv:1502.04446</a> <span> [<a href="https://arxiv.org/pdf/1502.04446">pdf</a>, <a href="https://arxiv.org/format/1502.04446">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Electron counting in a silicon single-electron pump </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Rossi%2C+A">Alessandro Rossi</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">Kuan Yen Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Huhtinen%2C+K">Kukka-Emilia Huhtinen</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%B6tt%C3%B6nen%2C+M">Mikko M枚tt枚nen</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</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="1502.04446v2-abstract-short" style="display: inline;"> We report electron counting experiments in a silicon metal-oxide-semiconductor quantum dot architecture which has been previously demonstrated to generate a quantized current in excess of 80 pA with uncertainty below 30 parts per million. Single-shot detection of electrons pumped into a reservoir dot is performed using a capacitively coupled single-electron transistor. We extract the full probabil… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.04446v2-abstract-full').style.display = 'inline'; document.getElementById('1502.04446v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1502.04446v2-abstract-full" style="display: none;"> We report electron counting experiments in a silicon metal-oxide-semiconductor quantum dot architecture which has been previously demonstrated to generate a quantized current in excess of 80 pA with uncertainty below 30 parts per million. Single-shot detection of electrons pumped into a reservoir dot is performed using a capacitively coupled single-electron transistor. We extract the full probability distribution of the transfer of n electrons per pumping cycle for n = 0, 1, 2, 3, and 4. We find that the probabilities extracted from the counting experiment are in agreement with direct current measurements in a broad range of dc electrochemical potentials of the pump. The electron counting technique is also used to confirm the improving robustness of the pumping mechanism with increasing electrostatic confinement of the quantum dot. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.04446v2-abstract-full').style.display = 'none'; document.getElementById('1502.04446v2-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 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 February, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">4 pages, 3 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/1406.1267">arXiv:1406.1267</a> <span> [<a href="https://arxiv.org/pdf/1406.1267">pdf</a>, <a href="https://arxiv.org/format/1406.1267">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1021/nl500927q">10.1021/nl500927q <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An accurate single-electron pump based on a highly tunable silicon quantum dot </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Rossi%2C+A">A. Rossi</a>, <a href="/search/cond-mat?searchtype=author&query=Tanttu%2C+T">T. Tanttu</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">K. Y. Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Iisakka%2C+I">I. Iisakka</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+R">R. Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Tettamanzi%2C+G+C">G. C. Tettamanzi</a>, <a href="/search/cond-mat?searchtype=author&query=Rogge%2C+S">S. Rogge</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%B6tt%C3%B6nen%2C+M">M. M枚tt枚nen</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="1406.1267v1-abstract-short" style="display: inline;"> Nanoscale single-electron pumps can be used to generate accurate currents, and can potentially serve to realize a new standard of electrical current based on elementary charge. Here, we use a silicon-based quantum dot with tunable tunnel barriers as an accurate source of quantized current. The charge transfer accuracy of our pump can be dramatically enhanced by controlling the electrostatic confin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.1267v1-abstract-full').style.display = 'inline'; document.getElementById('1406.1267v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1406.1267v1-abstract-full" style="display: none;"> Nanoscale single-electron pumps can be used to generate accurate currents, and can potentially serve to realize a new standard of electrical current based on elementary charge. Here, we use a silicon-based quantum dot with tunable tunnel barriers as an accurate source of quantized current. The charge transfer accuracy of our pump can be dramatically enhanced by controlling the electrostatic confinement of the dot using purposely engineered gate electrodes. Improvements in the operational robustness, as well as suppression of non-adiabatic transitions that reduce pumping accuracy, are achieved via small adjustments of the gate voltages. We can produce an output current in excess of 80 pA with experimentally determined relative uncertainty below 50 parts per million. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.1267v1-abstract-full').style.display = 'none'; document.getElementById('1406.1267v1-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 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">12 pages, 7 figures, includes supplementary information, Nano Letters (2014)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nano Letters (2014), 14(6), pp. 3405-3411 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1103.5891">arXiv:1103.5891</a> <span> [<a href="https://arxiv.org/pdf/1103.5891">pdf</a>, <a href="https://arxiv.org/format/1103.5891">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="Materials Science">cond-mat.mtrl-sci</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/10.1063/1.3593491">10.1063/1.3593491 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Single-electron shuttle based on a silicon quantum dot </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Mottonen%2C+M">M. Mottonen</a>, <a href="/search/cond-mat?searchtype=author&query=Kemppinen%2C+A">A. Kemppinen</a>, <a href="/search/cond-mat?searchtype=author&query=Lai%2C+N+S">N. S. Lai</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">K. Y. Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Lim%2C+W+H">W. H. Lim</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</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="1103.5891v3-abstract-short" style="display: inline;"> We report on single-electron shuttling experiments with a silicon metal-oxide-semiconductor quantum dot at 300 mK. Our system consists of an accumulated electron layer at the Si/SiO_2 interface below an aluminum top gate with two additional barrier gates used to deplete the electron gas locally and to define a quantum dot. Directional single-electron shuttling from the source and to the drain lead… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1103.5891v3-abstract-full').style.display = 'inline'; document.getElementById('1103.5891v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1103.5891v3-abstract-full" style="display: none;"> We report on single-electron shuttling experiments with a silicon metal-oxide-semiconductor quantum dot at 300 mK. Our system consists of an accumulated electron layer at the Si/SiO_2 interface below an aluminum top gate with two additional barrier gates used to deplete the electron gas locally and to define a quantum dot. Directional single-electron shuttling from the source and to the drain lead is achieved by applying a dc source-drain bias while driving the barrier gates with an ac voltage of frequency f_p. Current plateaus at integer levels of ef_p are observed up to f_p = 240 MHz operation frequencies. The observed results are explained by a sequential tunneling model which suggests that the electron gas may be heated substantially by the ac driving voltage. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1103.5891v3-abstract-full').style.display = 'none'; document.getElementById('1103.5891v3-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 October, 2011; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 March, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2011. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Appl. Phys. Lett. 98, 212103 (2011) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1003.2679">arXiv:1003.2679</a> <span> [<a href="https://arxiv.org/pdf/1003.2679">pdf</a>, <a href="https://arxiv.org/format/1003.2679">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="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/nature09392">10.1038/nature09392 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Single-shot readout of an electron spin in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">Andrea Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Pla%2C+J+J">Jarryd J. Pla</a>, <a href="/search/cond-mat?searchtype=author&query=Zwanenburg%2C+F+A">Floris A. Zwanenburg</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Huebl%2C+H">Hans Huebl</a>, <a href="/search/cond-mat?searchtype=author&query=Mottonen%2C+M">Mikko Mottonen</a>, <a href="/search/cond-mat?searchtype=author&query=Nugroho%2C+C+D">Christopher D. Nugroho</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C">Changyi Yang</a>, <a href="/search/cond-mat?searchtype=author&query=van+Donkelaar%2C+J+A">Jessica A. van Donkelaar</a>, <a href="/search/cond-mat?searchtype=author&query=Alves%2C+A+D+C">Andrew D. C. Alves</a>, <a href="/search/cond-mat?searchtype=author&query=Jamieson%2C+D+N">David N. Jamieson</a>, <a href="/search/cond-mat?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/cond-mat?searchtype=author&query=Hollenberg%2C+L+C+L">Lloyd C. L. Hollenberg</a>, <a href="/search/cond-mat?searchtype=author&query=Clark%2C+R+G">Robert G. Clark</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</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="1003.2679v3-abstract-short" style="display: inline;"> The size of silicon transistors used in microelectronic devices is shrinking to the level where quantum effects become important. While this presents a significant challenge for the further scaling of microprocessors, it provides the potential for radical innovations in the form of spin-based quantum computers and spintronic devices. An electron spin in Si can represent a well-isolated quantum bit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1003.2679v3-abstract-full').style.display = 'inline'; document.getElementById('1003.2679v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1003.2679v3-abstract-full" style="display: none;"> The size of silicon transistors used in microelectronic devices is shrinking to the level where quantum effects become important. While this presents a significant challenge for the further scaling of microprocessors, it provides the potential for radical innovations in the form of spin-based quantum computers and spintronic devices. An electron spin in Si can represent a well-isolated quantum bit with long coherence times because of the weak spin-orbit coupling and the possibility to eliminate nuclear spins from the bulk crystal. However, the control of single electrons in Si has proved challenging, and has so far hindered the observation and manipulation of a single spin. Here we report the first demonstration of single-shot, time-resolved readout of an electron spin in Si. This has been performed in a device consisting of implanted phosphorus donors coupled to a metal-oxide-semiconductor single-electron transistor - compatible with current microelectronic technology. We observed a spin lifetime approaching 1 second at magnetic fields below 2 T, and achieved spin readout fidelity better than 90%. High-fidelity single-shot spin readout in Si opens the path to the development of a new generation of quantum computing and spintronic devices, built using the most important material in the semiconductor industry. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1003.2679v3-abstract-full').style.display = 'none'; document.getElementById('1003.2679v3-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 May, 2010; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 March, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2010. </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> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 467, 687 (2010) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0910.0731">arXiv:0910.0731</a> <span> [<a href="https://arxiv.org/pdf/0910.0731">pdf</a>, <a href="https://arxiv.org/ps/0910.0731">ps</a>, <a href="https://arxiv.org/format/0910.0731">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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.81.161304">10.1103/PhysRevB.81.161304 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Probe and Control of the Reservoir Density of States in Single-Electron Devices </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Mottonen%2C+M">M. Mottonen</a>, <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">K. Y. Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Zwanenburg%2C+F+A">F. A. Zwanenburg</a>, <a href="/search/cond-mat?searchtype=author&query=Lim%2C+W+H">W. H. Lim</a>, <a href="/search/cond-mat?searchtype=author&query=Escott%2C+C+C">C. C. Escott</a>, <a href="/search/cond-mat?searchtype=author&query=Pirkkalainen%2C+J+-">J. -M. Pirkkalainen</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">A. Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C">C. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=van+Donkelaar%2C+J+A">J. A. van Donkelaar</a>, <a href="/search/cond-mat?searchtype=author&query=Alves%2C+A+D+C">A. D. C. Alves</a>, <a href="/search/cond-mat?searchtype=author&query=Jamieson%2C+D+N">D. N. Jamieson</a>, <a href="/search/cond-mat?searchtype=author&query=Hollenberg%2C+L+C+L">L. C. L. Hollenberg</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</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="0910.0731v1-abstract-short" style="display: inline;"> We present a systematic study of quasi-one-dimensional density of states (DOS) in electron accumulation layers near a Si-SiO2 interface. In the experiments we have employed two conceptually different objects to probe DOS, namely, a phosphorus donor and a quantum dot, both operating in the single-electron tunneling regime. We demonstrate how the peaks in DOS can be moved in the transport window i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0910.0731v1-abstract-full').style.display = 'inline'; document.getElementById('0910.0731v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0910.0731v1-abstract-full" style="display: none;"> We present a systematic study of quasi-one-dimensional density of states (DOS) in electron accumulation layers near a Si-SiO2 interface. In the experiments we have employed two conceptually different objects to probe DOS, namely, a phosphorus donor and a quantum dot, both operating in the single-electron tunneling regime. We demonstrate how the peaks in DOS can be moved in the transport window independently of the other device properties, and in agreement with the theoretical analysis. This method introduces a fast and convenient way of identifying excited states in these emerging nanostructures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0910.0731v1-abstract-full').style.display = 'none'; document.getElementById('0910.0731v1-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 October, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2009. </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. B 81, 161304 (2010) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0910.0576">arXiv:0910.0576</a> <span> [<a href="https://arxiv.org/pdf/0910.0576">pdf</a>, <a href="https://arxiv.org/format/0910.0576">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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/10.1063/1.3272858">10.1063/1.3272858 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of the single-electron regime in a highly tunable silicon quantum dot </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lim%2C+W+H">W. H. Lim</a>, <a href="/search/cond-mat?searchtype=author&query=Zwanenburg%2C+F+A">F. A. Zwanenburg</a>, <a href="/search/cond-mat?searchtype=author&query=Huebl%2C+H">H. Huebl</a>, <a href="/search/cond-mat?searchtype=author&query=Mottonen%2C+M">M. Mottonen</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">A. Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</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="0910.0576v3-abstract-short" style="display: inline;"> We report on low-temperature electronic transport measurements of a silicon metal-oxide-semiconductor quantum dot, with independent gate control of electron densities in the leads and the quantum dot island. This architecture allows the dot energy levels to be probed without affecting the electron density in the leads, and vice versa. Appropriate gate biasing enables the dot occupancy to be redu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0910.0576v3-abstract-full').style.display = 'inline'; document.getElementById('0910.0576v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0910.0576v3-abstract-full" style="display: none;"> We report on low-temperature electronic transport measurements of a silicon metal-oxide-semiconductor quantum dot, with independent gate control of electron densities in the leads and the quantum dot island. This architecture allows the dot energy levels to be probed without affecting the electron density in the leads, and vice versa. Appropriate gate biasing enables the dot occupancy to be reduced to the single-electron level, as evidenced by magnetospectroscopy measurements of the ground state of the first two charge transitions. Independent gate control of the electron reservoirs also enables discrimination between excited states of the dot and density of states modulations in the leads. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0910.0576v3-abstract-full').style.display = 'none'; document.getElementById('0910.0576v3-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 November, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 October, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2009. </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, 3 figures, accepted for Applied Physics Letters</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Appl. Phys. Lett. 95, 242102 (2009) (3 pages) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0905.4358">arXiv:0905.4358</a> <span> [<a href="https://arxiv.org/pdf/0905.4358">pdf</a>, <a href="https://arxiv.org/format/0905.4358">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Transport Spectroscopy of Single Phosphorus Donors in a Silicon Nanoscale Transistor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Tan%2C+K+Y">Kuan Yen Tan</a>, <a href="/search/cond-mat?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%B6tt%C3%B6nen%2C+M">Mikko M枚tt枚nen</a>, <a href="/search/cond-mat?searchtype=author&query=Morello%2C+A">Andrea Morello</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+C">Changyi Yang</a>, <a href="/search/cond-mat?searchtype=author&query=van+Donkelaar%2C+J">Jessica van Donkelaar</a>, <a href="/search/cond-mat?searchtype=author&query=Alves%2C+A">Andrew Alves</a>, <a href="/search/cond-mat?searchtype=author&query=Pirkkalainen%2C+J">Juha-Matti Pirkkalainen</a>, <a href="/search/cond-mat?searchtype=author&query=Jamieson%2C+D+N">David N. Jamieson</a>, <a href="/search/cond-mat?searchtype=author&query=Clark%2C+R+G">Robert G. Clark</a>, <a href="/search/cond-mat?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</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="0905.4358v4-abstract-short" style="display: inline;"> We have developed nano-scale double-gated field-effect-transistors for the study of electron states and transport properties of single deliberately-implanted phosphorus donors. The devices provide a high-level of control of key parameters required for potential applications in nanoelectronics. For the donors, we resolve transitions corresponding to two charge states successively occupied by spin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0905.4358v4-abstract-full').style.display = 'inline'; document.getElementById('0905.4358v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0905.4358v4-abstract-full" style="display: none;"> We have developed nano-scale double-gated field-effect-transistors for the study of electron states and transport properties of single deliberately-implanted phosphorus donors. The devices provide a high-level of control of key parameters required for potential applications in nanoelectronics. For the donors, we resolve transitions corresponding to two charge states successively occupied by spin down and spin up electrons. The charging energies and the Lande g-factors are consistent with expectations for donors in gated nanostructures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0905.4358v4-abstract-full').style.display = 'none'; document.getElementById('0905.4358v4-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 February, 2010; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 May, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2009. </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, journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nano Letters 10, 11 (2010) </p> </li> 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