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<div class="control is-expanded"> <label for="query" class="hidden-label">Search term or terms</label> <input class="input is-medium" id="query" name="query" placeholder="Search term..." type="text" value="Bal, M"> </div> <div class="select control is-medium"> <label class="is-hidden" for="searchtype">Field</label> <select class="is-medium" id="searchtype" name="searchtype"><option value="all">All fields</option><option value="title">Title</option><option selected value="author">Author(s)</option><option value="abstract">Abstract</option><option value="comments">Comments</option><option value="journal_ref">Journal reference</option><option value="acm_class">ACM classification</option><option value="msc_class">MSC classification</option><option value="report_num">Report number</option><option value="paper_id">arXiv identifier</option><option value="doi">DOI</option><option value="orcid">ORCID</option><option value="license">License (URI)</option><option value="author_id">arXiv author 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name="searchtype"><option value="all">All fields</option><option value="title">Title</option><option selected value="author">Author(s)</option><option value="abstract">Abstract</option><option value="comments">Comments</option><option value="journal_ref">Journal reference</option><option value="acm_class">ACM classification</option><option value="msc_class">MSC classification</option><option value="report_num">Report number</option><option value="paper_id">arXiv identifier</option><option value="doi">DOI</option><option value="orcid">ORCID</option><option value="license">License (URI)</option><option value="author_id">arXiv author ID</option><option value="help">Help pages</option><option value="full_text">Full text</option></select> <input id="query" name="query" type="text" value="Bal, M"> <ul id="abstracts"><li><input checked id="abstracts-0" name="abstracts" type="radio" value="show"> <label for="abstracts-0">Show abstracts</label></li><li><input id="abstracts-1" name="abstracts" 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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/2409.09926">arXiv:2409.09926</a> <span> [<a href="https://arxiv.org/pdf/2409.09926">pdf</a>, <a href="https://arxiv.org/format/2409.09926">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Disentangling the Impact of Quasiparticles and Two-Level Systems on the Statistics of Superconducting Qubit Lifetime </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+S">Shaojiang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+X">Xinyuan You</a>, <a href="/search/quant-ph?searchtype=author&query=Alyanak%2C+U">Ugur Alyanak</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Mustafa Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Crisa%2C+F">Francesco Crisa</a>, <a href="/search/quant-ph?searchtype=author&query=Garattoni%2C+S">Sabrina Garattoni</a>, <a href="/search/quant-ph?searchtype=author&query=Lunin%2C+A">Andrei Lunin</a>, <a href="/search/quant-ph?searchtype=author&query=Pilipenko%2C+R">Roman Pilipenko</a>, <a href="/search/quant-ph?searchtype=author&query=Murthy%2C+A">Akshay Murthy</a>, <a href="/search/quant-ph?searchtype=author&query=Romanenko%2C+A">Alexander Romanenko</a>, <a href="/search/quant-ph?searchtype=author&query=Grassellino%2C+A">Anna Grassellino</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="2409.09926v2-abstract-short" style="display: inline;"> Temporal fluctuations in the superconducting qubit lifetime, $T_1$, bring up additional challenges in building a fault-tolerant quantum computer. While the exact mechanisms remain unclear, $T_1$ fluctuations are generally attributed to the strong coupling between the qubit and a few near-resonant two-level systems (TLSs) that can exchange energy with an assemble of thermally fluctuating two-level… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.09926v2-abstract-full').style.display = 'inline'; document.getElementById('2409.09926v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.09926v2-abstract-full" style="display: none;"> Temporal fluctuations in the superconducting qubit lifetime, $T_1$, bring up additional challenges in building a fault-tolerant quantum computer. While the exact mechanisms remain unclear, $T_1$ fluctuations are generally attributed to the strong coupling between the qubit and a few near-resonant two-level systems (TLSs) that can exchange energy with an assemble of thermally fluctuating two-level fluctuators (TLFs) at low frequencies. Here, we report $T_1$ measurements on the qubits with different geometrical footprints and surface dielectrics as a function of the temperature. By analyzing the noise spectrum of the qubit depolarization rate, $螕_1 = 1/T_1$, we can disentangle the impact of TLSs, non-equilibrium quasiparticles (QPs), and equilibrium (thermally excited) QPs on the variance in $螕_1$. We find that $螕_1$ variances in the qubit with a small footprint are more susceptible to the QP and TLS fluctuations than those in the large-footprint qubits. Furthermore, the QP-induced variances in all qubits are consistent with the theoretical framework of QP diffusion and fluctuation. We suggest these findings can offer valuable insights for future qubit design and engineering optimization. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.09926v2-abstract-full').style.display = 'none'; document.getElementById('2409.09926v2-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 February, 2025; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">6+5 pages, 3+4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> FERMILAB-PUB-24-0577-SQMS </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.18355">arXiv:2405.18355</a> <span> [<a href="https://arxiv.org/pdf/2405.18355">pdf</a>, <a href="https://arxiv.org/format/2405.18355">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Evaluating radiation impact on transmon qubits in above and underground facilities </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=De+Dominicis%2C+F">Francesco De Dominicis</a>, <a href="/search/quant-ph?searchtype=author&query=Roy%2C+T">Tanay Roy</a>, <a href="/search/quant-ph?searchtype=author&query=Mariani%2C+A">Ambra Mariani</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Mustafa Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Casali%2C+N">Nicola Casali</a>, <a href="/search/quant-ph?searchtype=author&query=Colantoni%2C+I">Ivan Colantoni</a>, <a href="/search/quant-ph?searchtype=author&query=Crisa%2C+F">Francesco Crisa</a>, <a href="/search/quant-ph?searchtype=author&query=Cruciani%2C+A">Angelo Cruciani</a>, <a href="/search/quant-ph?searchtype=author&query=Ferroni%2C+F">Fernando Ferroni</a>, <a href="/search/quant-ph?searchtype=author&query=Helis%2C+D+L">Dounia L Helis</a>, <a href="/search/quant-ph?searchtype=author&query=Pagnanini%2C+L">Lorenzo Pagnanini</a>, <a href="/search/quant-ph?searchtype=author&query=Pettinacci%2C+V">Valerio Pettinacci</a>, <a href="/search/quant-ph?searchtype=author&query=Pilipenko%2C+R">Roman Pilipenko</a>, <a href="/search/quant-ph?searchtype=author&query=Pirro%2C+S">Stefano Pirro</a>, <a href="/search/quant-ph?searchtype=author&query=Puiu%2C+A">Andrei Puiu</a>, <a href="/search/quant-ph?searchtype=author&query=Romanenko%2C+A">Alexander Romanenko</a>, <a href="/search/quant-ph?searchtype=author&query=Vignati%2C+M">Marco Vignati</a>, <a href="/search/quant-ph?searchtype=author&query=Zanten%2C+D+v">David v Zanten</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+S">Shaojiang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Grassellino%2C+A">Anna Grassellino</a>, <a href="/search/quant-ph?searchtype=author&query=Cardani%2C+L">Laura Cardani</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="2405.18355v2-abstract-short" style="display: inline;"> Superconducting qubits can be sensitive to abrupt energy deposits caused by cosmic rays and ambient radioactivity. Previous studies have focused on understanding possible correlated effects over time and distance due to cosmic rays. In this study, for the first time, we directly compare the response of a transmon qubit measured initially at the Fermilab SQMS above-ground facilities and then at the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.18355v2-abstract-full').style.display = 'inline'; document.getElementById('2405.18355v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.18355v2-abstract-full" style="display: none;"> Superconducting qubits can be sensitive to abrupt energy deposits caused by cosmic rays and ambient radioactivity. Previous studies have focused on understanding possible correlated effects over time and distance due to cosmic rays. In this study, for the first time, we directly compare the response of a transmon qubit measured initially at the Fermilab SQMS above-ground facilities and then at the deep underground Gran Sasso Laboratory (INFN-LNGS, Italy). We observe same average qubit lifetime T$_1$ of roughly 80 microseconds at above and underground facilities. We then apply a fast decay detection protocol and investigate the time structure, sensitivity and relative rates of triggered events due to radiation versus intrinsic noise, comparing above and underground performance of several high-coherence qubits. Using gamma sources of variable activity we calibrate the response of the qubit to different levels of radiation in an environment with minimal background radiation. Results indicate that qubits respond to a strong gamma source and it is possible to detect particle impacts. However, when comparing above and underground results, we do not observe a difference in radiation induced-like events for these sapphire and niobium-based transmon qubits. We conclude that the majority of these events are not radiation related and to be attributed to other noise sources which by far dominate single qubit errors in modern transmon qubits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.18355v2-abstract-full').style.display = 'none'; document.getElementById('2405.18355v2-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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+7 pages, 7+5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> FERMILAB-PUB-24-0277-SQMS </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.13257">arXiv:2304.13257</a> <span> [<a href="https://arxiv.org/pdf/2304.13257">pdf</a>, <a href="https://arxiv.org/format/2304.13257">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</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/s41534-024-00840-x">10.1038/s41534-024-00840-x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Systematic Improvements in Transmon Qubit Coherence Enabled by Niobium Surface Encapsulation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Mustafa Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Murthy%2C+A+A">Akshay A. Murthy</a>, <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+S">Shaojiang Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Crisa%2C+F">Francesco Crisa</a>, <a href="/search/quant-ph?searchtype=author&query=You%2C+X">Xinyuan You</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+Z">Ziwen Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Roy%2C+T">Tanay Roy</a>, <a href="/search/quant-ph?searchtype=author&query=Lee%2C+J">Jaeyel Lee</a>, <a href="/search/quant-ph?searchtype=author&query=van+Zanten%2C+D">David van Zanten</a>, <a href="/search/quant-ph?searchtype=author&query=Pilipenko%2C+R">Roman Pilipenko</a>, <a href="/search/quant-ph?searchtype=author&query=Nekrashevich%2C+I">Ivan Nekrashevich</a>, <a href="/search/quant-ph?searchtype=author&query=Lunin%2C+A">Andrei Lunin</a>, <a href="/search/quant-ph?searchtype=author&query=Bafia%2C+D">Daniel Bafia</a>, <a href="/search/quant-ph?searchtype=author&query=Krasnikova%2C+Y">Yulia Krasnikova</a>, <a href="/search/quant-ph?searchtype=author&query=Kopas%2C+C+J">Cameron J. Kopas</a>, <a href="/search/quant-ph?searchtype=author&query=Lachman%2C+E+O">Ella O. Lachman</a>, <a href="/search/quant-ph?searchtype=author&query=Miller%2C+D">Duncan Miller</a>, <a href="/search/quant-ph?searchtype=author&query=Mutus%2C+J+Y">Josh Y. Mutus</a>, <a href="/search/quant-ph?searchtype=author&query=Reagor%2C+M+J">Matthew J. Reagor</a>, <a href="/search/quant-ph?searchtype=author&query=Cansizoglu%2C+H">Hilal Cansizoglu</a>, <a href="/search/quant-ph?searchtype=author&query=Marshall%2C+J">Jayss Marshall</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D+P">David P. Pappas</a>, <a href="/search/quant-ph?searchtype=author&query=Vu%2C+K">Kim Vu</a>, <a href="/search/quant-ph?searchtype=author&query=Yadavalli%2C+K">Kameshwar Yadavalli</a>, <a href="/search/quant-ph?searchtype=author&query=Oh%2C+J">Jin-Su Oh</a> , et al. (15 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="2304.13257v3-abstract-short" style="display: inline;"> We present a novel transmon qubit fabrication technique that yields systematic improvements in T$_1$ relaxation times. We fabricate devices using an encapsulation strategy that involves passivating the surface of niobium and thereby preventing the formation of its lossy surface oxide. By maintaining the same superconducting metal and only varying the surface structure, this comparative investigati… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.13257v3-abstract-full').style.display = 'inline'; document.getElementById('2304.13257v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.13257v3-abstract-full" style="display: none;"> We present a novel transmon qubit fabrication technique that yields systematic improvements in T$_1$ relaxation times. We fabricate devices using an encapsulation strategy that involves passivating the surface of niobium and thereby preventing the formation of its lossy surface oxide. By maintaining the same superconducting metal and only varying the surface structure, this comparative investigation examining different capping materials, such as tantalum, aluminum, titanium nitride, and gold, and film substrates across different qubit foundries definitively demonstrates the detrimental impact that niobium oxides have on the coherence times of superconducting qubits, compared to native oxides of tantalum, aluminum or titanium nitride. Our surface-encapsulated niobium qubit devices exhibit T$_1$ relaxation times 2 to 5 times longer than baseline niobium qubit devices with native niobium oxides. When capping niobium with tantalum, we obtain median qubit lifetimes above 300 microseconds, with maximum values up to 600 microseconds, that represent the highest lifetimes to date for superconducting qubits prepared on both sapphire and silicon. Our comparative structural and chemical analysis suggests why amorphous niobium oxides may induce higher losses compared to other amorphous oxides. These results are in line with high-accuracy measurements of the niobium oxide loss tangent obtained with ultra-high Q superconducting radiofrequency (SRF) cavities. This new surface encapsulation strategy enables even further reduction of dielectric losses via passivation with ambient-stable materials, while preserving fabrication and scalable manufacturability thanks to the compatibility with silicon processes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.13257v3-abstract-full').style.display = 'none'; document.getElementById('2304.13257v3-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 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Quantum Inf 10, 43 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.13024">arXiv:2207.13024</a> <span> [<a href="https://arxiv.org/pdf/2207.13024">pdf</a>, <a href="https://arxiv.org/format/2207.13024">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> High quality superconducting Nb co-planar resonators on sapphire substrate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhu%2C+S">S. Zhu</a>, <a href="/search/quant-ph?searchtype=author&query=Crisa%2C+F">F. Crisa</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">M. Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Murthy%2C+A+A">A. A. Murthy</a>, <a href="/search/quant-ph?searchtype=author&query=Lee%2C+J">J. Lee</a>, <a href="/search/quant-ph?searchtype=author&query=Sung%2C+Z">Z. Sung</a>, <a href="/search/quant-ph?searchtype=author&query=Lunin%2C+A">A. Lunin</a>, <a href="/search/quant-ph?searchtype=author&query=Frolov%2C+D">D. Frolov</a>, <a href="/search/quant-ph?searchtype=author&query=Pilipenko%2C+R">R. Pilipenko</a>, <a href="/search/quant-ph?searchtype=author&query=Bafia%2C+D">D. Bafia</a>, <a href="/search/quant-ph?searchtype=author&query=Mitra%2C+A">A. Mitra</a>, <a href="/search/quant-ph?searchtype=author&query=Romanenko%2C+A">A. Romanenko</a>, <a href="/search/quant-ph?searchtype=author&query=Grassellino%2C+A">A. Grassellino</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="2207.13024v1-abstract-short" style="display: inline;"> We present measurements and simulations of superconducting Nb co-planar waveguide resonators on sapphire substrate down to millikelvin temperature range with different readout powers. In the high temperature regime, we demonstrate that the Nb film residual surface resistance is comparable to that observed in the ultra-high quality, bulk Nb 3D superconducting radio frequency cavities while the reso… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.13024v1-abstract-full').style.display = 'inline'; document.getElementById('2207.13024v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.13024v1-abstract-full" style="display: none;"> We present measurements and simulations of superconducting Nb co-planar waveguide resonators on sapphire substrate down to millikelvin temperature range with different readout powers. In the high temperature regime, we demonstrate that the Nb film residual surface resistance is comparable to that observed in the ultra-high quality, bulk Nb 3D superconducting radio frequency cavities while the resonator quality is dominated by the BCS thermally excited quasiparticles. At low temperature both the resonator quality factor and frequency can be well explained using the two-level system models. Through the energy participation ratio simulations, we find that the two-level system loss tangent is $\sim 10^{-2}$, which agrees quite well with similar studies performed on the Nb 3D cavities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.13024v1-abstract-full').style.display = 'none'; document.getElementById('2207.13024v1-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.07716">arXiv:2206.07716</a> <span> [<a href="https://arxiv.org/pdf/2206.07716">pdf</a>, <a href="https://arxiv.org/format/2206.07716">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevResearch.5.043194">10.1103/PhysRevResearch.5.043194 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Implementing two-qubit gates at the quantum speed limit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Howard%2C+J">Joel Howard</a>, <a href="/search/quant-ph?searchtype=author&query=Lidiak%2C+A">Alexander Lidiak</a>, <a href="/search/quant-ph?searchtype=author&query=Jameson%2C+C">Casey Jameson</a>, <a href="/search/quant-ph?searchtype=author&query=Basyildiz%2C+B">Bora Basyildiz</a>, <a href="/search/quant-ph?searchtype=author&query=Clark%2C+K">Kyle Clark</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+T">Tongyu Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Mustafa Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Long%2C+J">Junling Long</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D+P">David P. Pappas</a>, <a href="/search/quant-ph?searchtype=author&query=Singh%2C+M">Meenakshi Singh</a>, <a href="/search/quant-ph?searchtype=author&query=Gong%2C+Z">Zhexuan Gong</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="2206.07716v4-abstract-short" style="display: inline;"> The speed of elementary quantum gates, particularly two-qubit gates, ultimately sets the limit on the speed at which quantum circuits can operate. In this work, we experimentally demonstrate commonly used two-qubit gates at nearly the fastest possible speed allowed by the physical interaction strength between two superconducting transmon qubits. We achieve this quantum speed limit by implementing… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.07716v4-abstract-full').style.display = 'inline'; document.getElementById('2206.07716v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.07716v4-abstract-full" style="display: none;"> The speed of elementary quantum gates, particularly two-qubit gates, ultimately sets the limit on the speed at which quantum circuits can operate. In this work, we experimentally demonstrate commonly used two-qubit gates at nearly the fastest possible speed allowed by the physical interaction strength between two superconducting transmon qubits. We achieve this quantum speed limit by implementing experimental gates designed using a machine learning inspired optimal control method. Importantly, our method only requires the single-qubit drive strength to be moderately larger than the interaction strength to achieve an arbitrary two-qubit gate close to its analytical speed limit with high fidelity. Thus, the method is applicable to a variety of platforms including those with comparable single-qubit and two-qubit gate speeds, or those with always-on interactions. We expect our method to offer significant speedups for non-native two-qubit gates that are typically achieved with a long sequence of single-qubit and native two-qubit gates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.07716v4-abstract-full').style.display = 'none'; document.getElementById('2206.07716v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">11 pages, 9 figures, accepted version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Research 5, 043194 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.12305">arXiv:2103.12305</a> <span> [<a href="https://arxiv.org/pdf/2103.12305">pdf</a>, <a href="https://arxiv.org/format/2103.12305">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A universal quantum gate set for transmon qubits with strong ZZ interactions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Long%2C+J">Junling Long</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+T">Tongyu Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Mustafa Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+R">Ruichen Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Barron%2C+G+S">George S. Barron</a>, <a href="/search/quant-ph?searchtype=author&query=Ku%2C+H">Hsiang-sheng Ku</a>, <a href="/search/quant-ph?searchtype=author&query=Howard%2C+J+A">Joel A. Howard</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+X">Xian Wu</a>, <a href="/search/quant-ph?searchtype=author&query=McRae%2C+C+R+H">Corey Rae H. McRae</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+X">Xiu-Hao Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Ribeill%2C+G+J">Guilhem J. Ribeill</a>, <a href="/search/quant-ph?searchtype=author&query=Singh%2C+M">Meenakshi Singh</a>, <a href="/search/quant-ph?searchtype=author&query=Ohki%2C+T+A">Thomas A. Ohki</a>, <a href="/search/quant-ph?searchtype=author&query=Barnes%2C+E">Edwin Barnes</a>, <a href="/search/quant-ph?searchtype=author&query=Economou%2C+S+E">Sophia E. Economou</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D+P">David P. Pappas</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="2103.12305v1-abstract-short" style="display: inline;"> High-fidelity single- and two-qubit gates are essential building blocks for a fault-tolerant quantum computer. While there has been much progress in suppressing single-qubit gate errors in superconducting qubit systems, two-qubit gates still suffer from error rates that are orders of magnitude higher. One limiting factor is the residual ZZ-interaction, which originates from a coupling between comp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.12305v1-abstract-full').style.display = 'inline'; document.getElementById('2103.12305v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.12305v1-abstract-full" style="display: none;"> High-fidelity single- and two-qubit gates are essential building blocks for a fault-tolerant quantum computer. While there has been much progress in suppressing single-qubit gate errors in superconducting qubit systems, two-qubit gates still suffer from error rates that are orders of magnitude higher. One limiting factor is the residual ZZ-interaction, which originates from a coupling between computational states and higher-energy states. While this interaction is usually viewed as a nuisance, here we experimentally demonstrate that it can be exploited to produce a universal set of fast single- and two-qubit entangling gates in a coupled transmon qubit system. To implement arbitrary single-qubit rotations, we design a new protocol called the two-axis gate that is based on a three-part composite pulse. It rotates a single qubit independently of the state of the other qubit despite the strong ZZ-coupling. We achieve single-qubit gate fidelities as high as 99.1% from randomized benchmarking measurements. We then demonstrate both a CZ gate and a CNOT gate. Because the system has a strong ZZ-interaction, a CZ gate can be achieved by letting the system freely evolve for a gate time $t_g=53.8$ ns. To design the CNOT gate, we utilize an analytical microwave pulse shape based on the SWIPHT protocol for realizing fast, low-leakage gates. We obtain fidelities of 94.6% and 97.8% for the CNOT and CZ gates respectively from quantum progress tomography. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.12305v1-abstract-full').style.display = 'none'; document.getElementById('2103.12305v1-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 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.10101">arXiv:2009.10101</a> <span> [<a href="https://arxiv.org/pdf/2009.10101">pdf</a>, <a href="https://arxiv.org/format/2009.10101">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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/10.1063/5.0029855">10.1063/5.0029855 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Cryogenic microwave loss in epitaxial Al/GaAs/Al trilayers for superconducting circuits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=McRae%2C+C+R+H">C. R. H. McRae</a>, <a href="/search/quant-ph?searchtype=author&query=McFadden%2C+A">A. McFadden</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+R">R. Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">H. Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Long%2C+J+L">J. L. Long</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+T">T. Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+S">S. Park</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">M. Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Palmstr%C3%B8m%2C+C+J">C. J. Palmstr酶m</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D+P">D. P. Pappas</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2009.10101v2-abstract-short" style="display: inline;"> Epitaxially-grown superconductor/dielectric/superconductor trilayers have the potential to form high-performance superconducting quantum devices and may even allow scalable superconducting quantum computing with low-surface-area qubits such as the merged-element transmon. In this work, we measure the power-independent loss and two-level-state (TLS) loss of epitaxial, wafer-bonded, and substrate-re… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.10101v2-abstract-full').style.display = 'inline'; document.getElementById('2009.10101v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.10101v2-abstract-full" style="display: none;"> Epitaxially-grown superconductor/dielectric/superconductor trilayers have the potential to form high-performance superconducting quantum devices and may even allow scalable superconducting quantum computing with low-surface-area qubits such as the merged-element transmon. In this work, we measure the power-independent loss and two-level-state (TLS) loss of epitaxial, wafer-bonded, and substrate-removed Al/GaAs/Al trilayers by measuring lumped element superconducting microwave resonators at millikelvin temperatures and down to single photon powers. The power-independent loss of the device is $(4.8 \pm 0.1) \times 10^{-5}$ and resonator-induced intrinsic TLS loss is $(6.4 \pm 0.2) \times 10^{-5}$. Dielectric loss extraction is used to determine a lower bound of the intrinsic TLS loss of the trilayer of $7.2 \times 10^{-5}$. The unusually high power-independent loss is attributed to GaAs's intrinsic piezoelectricity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.10101v2-abstract-full').style.display = 'none'; document.getElementById('2009.10101v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2008.07652">arXiv:2008.07652</a> <span> [<a href="https://arxiv.org/pdf/2008.07652">pdf</a>, <a href="https://arxiv.org/format/2008.07652">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> <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/10.1103/PhysRevApplied.14.064006">10.1103/PhysRevApplied.14.064006 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Merged-element transmon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+R">R. Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Park%2C+S">S. Park</a>, <a href="/search/quant-ph?searchtype=author&query=Zhao%2C+T">T. Zhao</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">M. Bal</a>, <a href="/search/quant-ph?searchtype=author&query=McRae%2C+C+R+H">C. R. H. McRae</a>, <a href="/search/quant-ph?searchtype=author&query=Long%2C+J">J. Long</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D+P">D. P. Pappas</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="2008.07652v5-abstract-short" style="display: inline;"> Transmon qubits are ubiquitous in the pursuit of quantum computing using superconducting circuits. However, they have some drawbacks that still need to be addressed. Most importantly, the scalability of transmons is limited by the large device footprint needed to reduce the participation of the lossy capacitive parts of the circuit. In this work, we investigate and evaluate losses in an alternativ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.07652v5-abstract-full').style.display = 'inline'; document.getElementById('2008.07652v5-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2008.07652v5-abstract-full" style="display: none;"> Transmon qubits are ubiquitous in the pursuit of quantum computing using superconducting circuits. However, they have some drawbacks that still need to be addressed. Most importantly, the scalability of transmons is limited by the large device footprint needed to reduce the participation of the lossy capacitive parts of the circuit. In this work, we investigate and evaluate losses in an alternative device geometry, namely, the merged-element transmon (mergemon). To this end, we replace the large external shunt capacitor of a traditional transmon with the intrinsic capacitance of a Josephson junction (JJ) and achieve an approximately 100 times reduction in qubit dimensions. We report the implementation of the mergemon using a sputtered Nb--amorphous-Si--Nb trilayer film. In an experiment below 10 mK, the frequency of the readout resonator, capacitively coupled to the mergemon, exhibits a qubit-state dependent shift in the low power regime. The device also demonstrates the single- and multi-photon transitions that represent a weakly anharmonic system in the two-tone spectroscopy. The transition spectra are explained well with master-equation simulations. A participation ratio analysis identifies the dielectric loss of the a-Si tunnel barrier and its interfaces as the dominant source for qubit relaxation. We expect the mergemon to achieve high coherence in relatively small device dimensions when implemented using a low-loss, epitaxially-grown, and lattice-matched trilayer. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.07652v5-abstract-full').style.display = 'none'; document.getElementById('2008.07652v5-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 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">Comments:</span> <span class="has-text-grey-dark mathjax">6 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/2003.12087">arXiv:2003.12087</a> <span> [<a href="https://arxiv.org/pdf/2003.12087">pdf</a>, <a href="https://arxiv.org/format/2003.12087">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="Strongly Correlated Electrons">cond-mat.str-el</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/s41534-021-00420-3">10.1038/s41534-021-00420-3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Parallel Quantum Simulation of Large Systems on Small Quantum Computers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Barratt%2C+F">Fergus Barratt</a>, <a href="/search/quant-ph?searchtype=author&query=Dborin%2C+J">James Dborin</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Matthias Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Stojevic%2C+V">Vid Stojevic</a>, <a href="/search/quant-ph?searchtype=author&query=Pollmann%2C+F">Frank Pollmann</a>, <a href="/search/quant-ph?searchtype=author&query=Green%2C+A+G">Andrew G. Green</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="2003.12087v2-abstract-short" style="display: inline;"> Tensor networks permit computational and entanglement resources to be concentrated in interesting regions of Hilbert space. Implemented on NISQ machines they allow simulation of quantum systems that are much larger than the computational machine itself. This is achieved by parallelising the quantum simulation. Here, we demonstrate this in the simplest case; an infinite, translationally invariant q… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.12087v2-abstract-full').style.display = 'inline'; document.getElementById('2003.12087v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2003.12087v2-abstract-full" style="display: none;"> Tensor networks permit computational and entanglement resources to be concentrated in interesting regions of Hilbert space. Implemented on NISQ machines they allow simulation of quantum systems that are much larger than the computational machine itself. This is achieved by parallelising the quantum simulation. Here, we demonstrate this in the simplest case; an infinite, translationally invariant quantum spin chain. We provide Cirq and Qiskit code that translate infinite, translationally invariant matrix product state (iMPS) algorithms to finite-depth quantum circuit machines, allowing the representation, optimisation and evolution arbitrary one-dimensional systems. Illustrative simulated output of these codes for achievable circuit sizes is given. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.12087v2-abstract-full').style.display = 'none'; document.getElementById('2003.12087v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 March, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Quantum Inf 7, 79 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2002.12248">arXiv:2002.12248</a> <span> [<a href="https://arxiv.org/pdf/2002.12248">pdf</a>, <a href="https://arxiv.org/format/2002.12248">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</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"> Non-trivial quantum magnetotransport oscillations in pure and robust topological $伪$-Sn films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Madarevic%2C+I">Ivan Madarevic</a>, <a href="/search/quant-ph?searchtype=author&query=Claessens%2C+N">Niels Claessens</a>, <a href="/search/quant-ph?searchtype=author&query=Seliverstov%2C+A">Aleksandr Seliverstov</a>, <a href="/search/quant-ph?searchtype=author&query=Van+Haesendonck%2C+C">Chris Van Haesendonck</a>, <a href="/search/quant-ph?searchtype=author&query=Van+Bael%2C+M+J">Margriet J. Van Bael</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2002.12248v2-abstract-short" style="display: inline;"> We report experimental evidence of topological Dirac fermion charge carriers in pure and robust $伪$-Sn films grown on InSb substrates. This evidence was acquired using standard macroscopic four-point contact resistance measurements, conducted on uncapped films with a significantly reduced bulk mobility. We analyzed and compared electrical characteristics of the constituting components of the $伪$-S… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.12248v2-abstract-full').style.display = 'inline'; document.getElementById('2002.12248v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2002.12248v2-abstract-full" style="display: none;"> We report experimental evidence of topological Dirac fermion charge carriers in pure and robust $伪$-Sn films grown on InSb substrates. This evidence was acquired using standard macroscopic four-point contact resistance measurements, conducted on uncapped films with a significantly reduced bulk mobility. We analyzed and compared electrical characteristics of the constituting components of the $伪$-Sn/InSb sample, and propose a three-band drift velocity model accordingly. A surface band, with low carrier density and high mobility, is identified as the origin of the observed Shubnikov -- de Haas oscillations. The analysis of these quantum oscillations results in a non-trivial value of the phase shift $纬=0$, characteristic for topologically protected Dirac fermions. For the same uncapped samples we estimate the momentum relaxation time $蟿\approx 300\ \mathrm{fs}$, which is significantly larger in comparison with the previous reports on grown $伪$-Sn films. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.12248v2-abstract-full').style.display = 'none'; document.getElementById('2002.12248v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1909.07428">arXiv:1909.07428</a> <span> [<a href="https://arxiv.org/pdf/1909.07428">pdf</a>, <a href="https://arxiv.org/format/1909.07428">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> </div> <div 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/10.1063/5.0004622">10.1063/5.0004622 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dielectric loss extraction for superconducting microwave resonators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=McRae%2C+C+R+H">C. R. H. McRae</a>, <a href="/search/quant-ph?searchtype=author&query=Lake%2C+R+E">R. E. Lake</a>, <a href="/search/quant-ph?searchtype=author&query=Long%2C+J+L">J. L. Long</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">M. Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+X">X. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Jugdersuren%2C+B">B. Jugdersuren</a>, <a href="/search/quant-ph?searchtype=author&query=Metcalf%2C+T+H">T. H. Metcalf</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+X">X. Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D+P">D. P. Pappas</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="1909.07428v2-abstract-short" style="display: inline;"> The investigation of two-level-state (TLS) loss in dielectric materials and interfaces remains at the forefront of materials research in superconducting quantum circuits. We demonstrate a method of TLS loss extraction of a thin film dielectric by measuring a lumped element resonator fabricated from a superconductor-dielectric-superconductor trilayer. We extract the dielectric loss by formulating a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.07428v2-abstract-full').style.display = 'inline'; document.getElementById('1909.07428v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1909.07428v2-abstract-full" style="display: none;"> The investigation of two-level-state (TLS) loss in dielectric materials and interfaces remains at the forefront of materials research in superconducting quantum circuits. We demonstrate a method of TLS loss extraction of a thin film dielectric by measuring a lumped element resonator fabricated from a superconductor-dielectric-superconductor trilayer. We extract the dielectric loss by formulating a circuit model for a lumped element resonator with TLS loss and then fitting to this model using measurements from a set of three resonator designs: a coplanar waveguide resonator, a lumped element resonator with an interdigitated capacitor, and a lumped element resonator with a parallel plate capacitor that includes the dielectric thin film of interest. Unlike other methods, this allows accurate measurement of materials with TLS loss lower than $10^{-6}$. We demonstrate this method by extracting a TLS loss of $1.02 \times 10^{-3}$ for sputtered $\mathrm{Al_2O_3}$ using a set of samples fabricated from an $\mathrm{Al/Al_2O_3/Al}$ trilayer. We observe a difference of 11$\%$ between extracted loss of the trilayer with and without the implementation of this method. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1909.07428v2-abstract-full').style.display = 'none'; document.getElementById('1909.07428v2-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 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2019. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1809.11048">arXiv:1809.11048</a> <span> [<a href="https://arxiv.org/pdf/1809.11048">pdf</a>, <a href="https://arxiv.org/format/1809.11048">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.5063252">10.1063/1.5063252 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Kinetic Inductance Traveling Wave Amplifiers For Multiplexed Qubit Readout </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ranzani%2C+L">Leonardo Ranzani</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Mustafa Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Fong%2C+K+C">Kin Chung Fong</a>, <a href="/search/quant-ph?searchtype=author&query=Ribeill%2C+G">Guilhem Ribeill</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+X">Xian Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Long%2C+J">Junling Long</a>, <a href="/search/quant-ph?searchtype=author&query=Ku%2C+H+S">Hsiang Sheng Ku</a>, <a href="/search/quant-ph?searchtype=author&query=Erickson%2C+R+P">Robert P. Erickson</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D">David Pappas</a>, <a href="/search/quant-ph?searchtype=author&query=Ohki%2C+T+A">Thomas A. Ohki</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="1809.11048v2-abstract-short" style="display: inline;"> We describe a kinetic inductance traveling-wave (KIT) amplifier suitable for superconducting quantum information measurements and characterize its wideband scattering and noise properties. We use mechanical microwave switches to calibrate the four amplifier scattering parameters up to the device input and output connectors at the dilution refrigerator base temperature and a tunable temperature loa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.11048v2-abstract-full').style.display = 'inline'; document.getElementById('1809.11048v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1809.11048v2-abstract-full" style="display: none;"> We describe a kinetic inductance traveling-wave (KIT) amplifier suitable for superconducting quantum information measurements and characterize its wideband scattering and noise properties. We use mechanical microwave switches to calibrate the four amplifier scattering parameters up to the device input and output connectors at the dilution refrigerator base temperature and a tunable temperature load to characterize the amplifier noise. Finally, we demonstrate the high fidelity simultaneous dispersive readout of two superconducting transmon qubits. The KIT amplifier provides low-noise amplification of both readout tones with readout fidelities of 83% and 89% and negligible effect on qubit lifetime and coherence. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.11048v2-abstract-full').style.display = 'none'; document.getElementById('1809.11048v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 September, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 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/1801.05959">arXiv:1801.05959</a> <span> [<a href="https://arxiv.org/pdf/1801.05959">pdf</a>, <a href="https://arxiv.org/format/1801.05959">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="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Lattice">hep-lat</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.121.177203">10.1103/PhysRevLett.121.177203 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Mapping topological to conformal field theories through strange correlators </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Matthias Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Williamson%2C+D+J">Dominic J. Williamson</a>, <a href="/search/quant-ph?searchtype=author&query=Vanhove%2C+R">Robijn Vanhove</a>, <a href="/search/quant-ph?searchtype=author&query=Bultinck%2C+N">Nick Bultinck</a>, <a href="/search/quant-ph?searchtype=author&query=Haegeman%2C+J">Jutho Haegeman</a>, <a href="/search/quant-ph?searchtype=author&query=Verstraete%2C+F">Frank Verstraete</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="1801.05959v1-abstract-short" style="display: inline;"> We extend the concept of strange correlators, defined for symmetry-protected phases in [You et al., Phys. Rev. Lett. 112, 247202 (2014)], to topological phases of matter by taking the inner product between string-net ground states and product states. The resulting two-dimensional partition functions are shown to be either critical or symmetry broken, as the corresponding transfer matrices inherit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.05959v1-abstract-full').style.display = 'inline'; document.getElementById('1801.05959v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1801.05959v1-abstract-full" style="display: none;"> We extend the concept of strange correlators, defined for symmetry-protected phases in [You et al., Phys. Rev. Lett. 112, 247202 (2014)], to topological phases of matter by taking the inner product between string-net ground states and product states. The resulting two-dimensional partition functions are shown to be either critical or symmetry broken, as the corresponding transfer matrices inherit all matrix product operator symmetries of the string-net states. For the case of critical systems, those non-local matrix product operator symmetries are the lattice remnants of topological conformal defects in the field theory description. Following [Aasen et al., J. Phys. A 49, 354001 (2016)], we argue that the different conformal boundary conditions can be obtained by applying the strange correlator concept to the different topological sectors of the string-net obtained from Ocneanu's tube algebra. This is demonstrated by calculating the conformal field theory spectra on the lattice in the different topological sectors for the Fibonacci/hard-hexagon and Ising string-net. Additionally, we provide a complementary perspective on symmetry-preserving real-space renormalization by showing how known tensor network renormalization methods can be understood as the approximate truncation of an exactly coarse-grained strange correlator. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.05959v1-abstract-full').style.display = 'none'; document.getElementById('1801.05959v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 January, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 121, 177203 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1705.08993">arXiv:1705.08993</a> <span> [<a href="https://arxiv.org/pdf/1705.08993">pdf</a>, <a href="https://arxiv.org/format/1705.08993">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="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/10.1063/1.4993937">10.1063/1.4993937 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Overlap junctions for high coherence superconducting qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wu%2C+X">X. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Long%2C+J+L">J. L. Long</a>, <a href="/search/quant-ph?searchtype=author&query=Ku%2C+H+S">H. S. Ku</a>, <a href="/search/quant-ph?searchtype=author&query=Lake%2C+R+E">R. E. Lake</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">M. Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D+P">D. P. Pappas</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1705.08993v1-abstract-short" style="display: inline;"> Fabrication of sub-micron Josephson junctions is demonstrated using standard processing techniques for high-coherence, superconducting qubits. These junctions are made in two separate lithography steps with normal-angle evaporation. Most significantly, this work demonstrates that it is possible to achieve high coherence with junctions formed on aluminum surfaces cleaned in situ with Ar milling bef… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.08993v1-abstract-full').style.display = 'inline'; document.getElementById('1705.08993v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1705.08993v1-abstract-full" style="display: none;"> Fabrication of sub-micron Josephson junctions is demonstrated using standard processing techniques for high-coherence, superconducting qubits. These junctions are made in two separate lithography steps with normal-angle evaporation. Most significantly, this work demonstrates that it is possible to achieve high coherence with junctions formed on aluminum surfaces cleaned in situ with Ar milling before the junction oxidation. This method eliminates the angle-dependent shadow masks typically used for small junctions. Therefore, this is conducive to the implementation of typical methods for improving margins and yield using conventional CMOS processing. The current method uses electron-beam lithography and an additive process to define the top and bottom electrodes. Extension of this work to optical lithography and subtractive processes is discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.08993v1-abstract-full').style.display = 'none'; document.getElementById('1705.08993v1-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, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">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/1704.08777">arXiv:1704.08777</a> <span> [<a href="https://arxiv.org/pdf/1704.08777">pdf</a>, <a href="https://arxiv.org/ps/1704.08777">ps</a>, <a href="https://arxiv.org/format/1704.08777">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.120.083602">10.1103/PhysRevLett.120.083602 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electromagnetically induced transparency in circuit QED with nested polariton states </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Long%2C+J">Junling Long</a>, <a href="/search/quant-ph?searchtype=author&query=Ku%2C+H+S">H. S. Ku</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+X">Xian Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Gu%2C+X">Xiu Gu</a>, <a href="/search/quant-ph?searchtype=author&query=Lake%2C+R+E">Russell E. Lake</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Mustafa Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Yu-xi Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D+P">David P. Pappas</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="1704.08777v2-abstract-short" style="display: inline;"> Electromagnetically induced transparency (EIT) is a signature of quantum interference in an atomic three-level system. By driving the dressed cavity-qubit states of a two-dimensional circuit QED system, we generate a set of polariton states in the nesting regime. The lowest three energy levels are utilized to form the $螞$-type system. EIT is observed and verified by Akaike's information criterion… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.08777v2-abstract-full').style.display = 'inline'; document.getElementById('1704.08777v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1704.08777v2-abstract-full" style="display: none;"> Electromagnetically induced transparency (EIT) is a signature of quantum interference in an atomic three-level system. By driving the dressed cavity-qubit states of a two-dimensional circuit QED system, we generate a set of polariton states in the nesting regime. The lowest three energy levels are utilized to form the $螞$-type system. EIT is observed and verified by Akaike's information criterion based testing. Negative group velocities up to $-0.52\pm0.09$ km/s are obtained based on the dispersion relation in the EIT transmission spectrum. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.08777v2-abstract-full').style.display = 'none'; document.getElementById('1704.08777v2-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 February, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 120, 083602 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1704.00803">arXiv:1704.00803</a> <span> [<a href="https://arxiv.org/pdf/1704.00803">pdf</a>, <a href="https://arxiv.org/ps/1704.00803">ps</a>, <a href="https://arxiv.org/format/1704.00803">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevA.96.042339">10.1103/PhysRevA.96.042339 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Qubit gates using hyperbolic secant pulses </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Ku%2C+H+S">H. S. Ku</a>, <a href="/search/quant-ph?searchtype=author&query=Long%2C+J+L">J. L. Long</a>, <a href="/search/quant-ph?searchtype=author&query=Wu%2C+X">X. Wu</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">M. Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Lake%2C+R+E">R. E. Lake</a>, <a href="/search/quant-ph?searchtype=author&query=Barnes%2C+E">Edwin Barnes</a>, <a href="/search/quant-ph?searchtype=author&query=Economou%2C+S+E">Sophia E. Economou</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D+P">D. P. Pappas</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="1704.00803v2-abstract-short" style="display: inline;"> It has been known since the early days of quantum mechanics that hyperbolic secant pulses possess the unique property that they can perform cyclic evolution on two-level quantum systems independently of the pulse detuning. More recently, it was realized that they induce detuning- controlled phases without changing state populations. Here, we experimentally demonstrate the properties of hyperbolic… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.00803v2-abstract-full').style.display = 'inline'; document.getElementById('1704.00803v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1704.00803v2-abstract-full" style="display: none;"> It has been known since the early days of quantum mechanics that hyperbolic secant pulses possess the unique property that they can perform cyclic evolution on two-level quantum systems independently of the pulse detuning. More recently, it was realized that they induce detuning- controlled phases without changing state populations. Here, we experimentally demonstrate the properties of hyperbolic secant pulses on superconducting transmon qubits and contrast them with the more commonly used Gaussian and square waves. We further show that these properties can be exploited to implement phase gates, nominally without exiting the computational subspace. This enables us to demonstrate the first microwave-driven Z-gates with a single control parameter, the detuning. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.00803v2-abstract-full').style.display = 'none'; document.getElementById('1704.00803v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 6 figures, added supplementary information</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 96, 042339 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1703.00365">arXiv:1703.00365</a> <span> [<a href="https://arxiv.org/pdf/1703.00365">pdf</a>, <a href="https://arxiv.org/format/1703.00365">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Lattice">hep-lat</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/PhysRevLett.118.250602">10.1103/PhysRevLett.118.250602 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Renormalization group flows of Hamiltonians using tensor networks </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Matthias Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Mari%C3%ABn%2C+M">Micha毛l Mari毛n</a>, <a href="/search/quant-ph?searchtype=author&query=Haegeman%2C+J">Jutho Haegeman</a>, <a href="/search/quant-ph?searchtype=author&query=Verstraete%2C+F">Frank Verstraete</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1703.00365v2-abstract-short" style="display: inline;"> A renormalization group flow of Hamiltonians for two-dimensional classical partition functions is constructed using tensor networks. Similar to tensor network renormalization ([G. Evenbly and G. Vidal, Phys. Rev. Lett. 115, 180405 (2015)], [S. Yang, Z.-C. Gu, and X.-G Wen, Phys. Rev. Lett. 118, 110504 (2017)]) we obtain approximate fixed point tensor networks at criticality. Our formalism however… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.00365v2-abstract-full').style.display = 'inline'; document.getElementById('1703.00365v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1703.00365v2-abstract-full" style="display: none;"> A renormalization group flow of Hamiltonians for two-dimensional classical partition functions is constructed using tensor networks. Similar to tensor network renormalization ([G. Evenbly and G. Vidal, Phys. Rev. Lett. 115, 180405 (2015)], [S. Yang, Z.-C. Gu, and X.-G Wen, Phys. Rev. Lett. 118, 110504 (2017)]) we obtain approximate fixed point tensor networks at criticality. Our formalism however preserves positivity of the tensors at every step and hence yields an interpretation in terms of Hamiltonian flows. We emphasize that the key difference between tensor network approaches and Kadanoff's spin blocking method can be understood in terms of a change of local basis at every decimation step, a property which is crucial to overcome the area law of mutual information. We derive algebraic relations for fixed point tensors, calculate critical exponents, and benchmark our method on the Ising model and the six-vertex model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.00365v2-abstract-full').style.display = 'none'; document.getElementById('1703.00365v2-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, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">accepted version for Phys. Rev. Lett, main text: 5 pages, 3 figures, appendices: 9 pages, 1 figure</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 118, 250602 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1509.01522">arXiv:1509.01522</a> <span> [<a href="https://arxiv.org/pdf/1509.01522">pdf</a>, <a href="https://arxiv.org/format/1509.01522">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="Statistical Mechanics">cond-mat.stat-mech</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</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.94.205122">10.1103/PhysRevB.94.205122 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Matrix product state renormalization </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Matthias Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Rams%2C+M+M">Marek M. Rams</a>, <a href="/search/quant-ph?searchtype=author&query=Zauner%2C+V">Valentin Zauner</a>, <a href="/search/quant-ph?searchtype=author&query=Haegeman%2C+J">Jutho Haegeman</a>, <a href="/search/quant-ph?searchtype=author&query=Verstraete%2C+F">Frank Verstraete</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="1509.01522v2-abstract-short" style="display: inline;"> The truncation or compression of the spectrum of Schmidt values is inherent to the matrix product state (MPS) approximation of one-dimensional quantum ground states. We provide a renormalization group picture by interpreting this compression as an application of Wilson's numerical renormalization group along the imaginary time direction appearing in the path integral representation of the state. T… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.01522v2-abstract-full').style.display = 'inline'; document.getElementById('1509.01522v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.01522v2-abstract-full" style="display: none;"> The truncation or compression of the spectrum of Schmidt values is inherent to the matrix product state (MPS) approximation of one-dimensional quantum ground states. We provide a renormalization group picture by interpreting this compression as an application of Wilson's numerical renormalization group along the imaginary time direction appearing in the path integral representation of the state. The location of the physical index is considered as an impurity in the transfer matrix and static MPS correlation functions are reinterpreted as dynamical impurity correlations. Coarse-graining the transfer matrix is performed using a hybrid variational ansatz based on matrix product operators, combining ideas of MPS and the multi-scale entanglement renormalization ansatz. Through numerical comparison with conventional MPS algorithms, we explicitly verify the impurity interpretation of MPS compression, as put forward by [V. Zauner et al., New J. Phys. 17, 053002 (2015)] for the transverse-field Ising model. Additionally, we motivate the conceptual usefulness of endowing MPS with an internal layered structure by studying restricted variational subspaces to describe elementary excitations on top of the ground state, which serves to elucidate a transparent renormalization group structure ingrained in MPS descriptions of ground states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.01522v2-abstract-full').style.display = 'none'; document.getElementById('1509.01522v2-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 November, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">15 pages, 10 figures, published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 94, 205122 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1411.2607">arXiv:1411.2607</a> <span> [<a href="https://arxiv.org/pdf/1411.2607">pdf</a>, <a href="https://arxiv.org/format/1411.2607">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="Statistical Mechanics">cond-mat.stat-mech</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.92.235150">10.1103/PhysRevB.92.235150 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Truncating an exact Matrix Product State for the XY model: transfer matrix and its renormalisation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Rams%2C+M+M">Marek M. Rams</a>, <a href="/search/quant-ph?searchtype=author&query=Zauner%2C+V">Valentin Zauner</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Matthias Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Haegeman%2C+J">Jutho Haegeman</a>, <a href="/search/quant-ph?searchtype=author&query=Verstraete%2C+F">Frank Verstraete</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1411.2607v2-abstract-short" style="display: inline;"> We discuss how to analytically obtain an -- essentially infinite -- Matrix Product State (MPS) representation of the ground state of the XY model. On the one hand this allows to illustrate how the Ornstein-Zernike form of the correlation function emerges in the exact case using standard MPS language. On the other hand we study the consequences of truncating the bond dimension of the exact MPS, whi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.2607v2-abstract-full').style.display = 'inline'; document.getElementById('1411.2607v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1411.2607v2-abstract-full" style="display: none;"> We discuss how to analytically obtain an -- essentially infinite -- Matrix Product State (MPS) representation of the ground state of the XY model. On the one hand this allows to illustrate how the Ornstein-Zernike form of the correlation function emerges in the exact case using standard MPS language. On the other hand we study the consequences of truncating the bond dimension of the exact MPS, which is also part of many tensor network algorithms, and analyze how the truncated MPS transfer matrix is representing the dominant part of the exact quantum transfer matrix. In the gapped phase we observe that the correlation length obtained from a truncated MPS approaches the exact value following a power law in effective bond dimension. In the gapless phase we find a good match between a state obtained numerically from standard MPS techniques with finite bond dimension, and a state obtained by effective finite imaginary time evolution in our framework. This provides a direct hint for a geometric interpretation of Finite Entanglement Scaling at the critical point in this case. Finally, by analyzing the spectra of transfer matrices, we support the interpretation put forward by [V. Zauner at. al., New J. Phys. 17, 053002 (2015)] that the MPS transfer matrix emerges from the quantum transfer matrix though the application of Wilson's Numerical Renormalisation Group along the imaginary-time direction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1411.2607v2-abstract-full').style.display = 'none'; document.getElementById('1411.2607v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 November, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 November, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 9 figures, significantly extended, comments welcome</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 92, 235150 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1407.1346">arXiv:1407.1346</a> <span> [<a href="https://arxiv.org/pdf/1407.1346">pdf</a>, <a href="https://arxiv.org/ps/1407.1346">ps</a>, <a href="https://arxiv.org/format/1407.1346">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="Superconductivity">cond-mat.supr-con</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.93.104518">10.1103/PhysRevB.93.104518 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Flux qubits in a planar circuit quantum electrodynamics architecture: quantum control and decoherence </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Orgiazzi%2C+J+-">J. -L. Orgiazzi</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+C">C. Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Layden%2C+D">D. Layden</a>, <a href="/search/quant-ph?searchtype=author&query=Marchildon%2C+R">R. Marchildon</a>, <a href="/search/quant-ph?searchtype=author&query=Kitapli%2C+F">F. Kitapli</a>, <a href="/search/quant-ph?searchtype=author&query=Shen%2C+F">F. Shen</a>, <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">M. Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Ong%2C+F+R">F. R. Ong</a>, <a href="/search/quant-ph?searchtype=author&query=Lupascu%2C+A">A. Lupascu</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="1407.1346v1-abstract-short" style="display: inline;"> We report experiments on superconducting flux qubits in a circuit quantum electrodynamics (cQED) setup. Two qubits, independently biased and controlled, are coupled to a coplanar waveguide resonator. Dispersive qubit state readout reaches a maximum contrast of $72\,\%$. We find intrinsic energy relaxation times at the symmetry point of $7\,渭\text{s}$ and $20\,渭\text{s}$ and levels of flux noise of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.1346v1-abstract-full').style.display = 'inline'; document.getElementById('1407.1346v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1407.1346v1-abstract-full" style="display: none;"> We report experiments on superconducting flux qubits in a circuit quantum electrodynamics (cQED) setup. Two qubits, independently biased and controlled, are coupled to a coplanar waveguide resonator. Dispersive qubit state readout reaches a maximum contrast of $72\,\%$. We find intrinsic energy relaxation times at the symmetry point of $7\,渭\text{s}$ and $20\,渭\text{s}$ and levels of flux noise of $2.6\,渭桅_0/\sqrt{\text{Hz}}$ and $2.7\,渭桅_0/\sqrt{\text{Hz}}$ at 1 Hz for the two qubits. We discuss the origin of decoherence in the measured devices. These results demonstrate the potential of cQED as a platform for fundamental investigations of decoherence and quantum dynamics of flux qubits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1407.1346v1-abstract-full').style.display = 'none'; document.getElementById('1407.1346v1-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 July, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">8 pages, including supplementary information</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 93, 104518 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1406.7350">arXiv:1406.7350</a> <span> [<a href="https://arxiv.org/pdf/1406.7350">pdf</a>, <a href="https://arxiv.org/ps/1406.7350">ps</a>, <a href="https://arxiv.org/format/1406.7350">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="Superconductivity">cond-mat.supr-con</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.91.195434">10.1103/PhysRevB.91.195434 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dynamics of parametric fluctuations induced by quasiparticle tunneling in superconducting flux qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">M. Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Ansari%2C+M+H">M. H. Ansari</a>, <a href="/search/quant-ph?searchtype=author&query=Orgiazzi%2C+J+-">J. -L. Orgiazzi</a>, <a href="/search/quant-ph?searchtype=author&query=Lutchyn%2C+R+M">R. M. Lutchyn</a>, <a href="/search/quant-ph?searchtype=author&query=Lupascu%2C+A">A. Lupascu</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="1406.7350v1-abstract-short" style="display: inline;"> We present experiments on the dynamics of a two-state parametric fluctuator in a superconducting flux qubit. In spectroscopic measurements, the fluctuator manifests itself as a doublet line. When the qubit is excited in resonance with one of the two doublet lines, the correlation of readout results exhibits an exponential time decay which provides a measure of the fluctuator transition rate. The r… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.7350v1-abstract-full').style.display = 'inline'; document.getElementById('1406.7350v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1406.7350v1-abstract-full" style="display: none;"> We present experiments on the dynamics of a two-state parametric fluctuator in a superconducting flux qubit. In spectroscopic measurements, the fluctuator manifests itself as a doublet line. When the qubit is excited in resonance with one of the two doublet lines, the correlation of readout results exhibits an exponential time decay which provides a measure of the fluctuator transition rate. The rate increases with temperature in the interval 40 to 158 mK. Based on the magnitude of the transition rate and the doublet line splitting we conclude that the fluctuation is induced by quasiparticle tunneling. These results demonstrate the importance of considering quasiparticles as a source of decoherence in flux qubits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1406.7350v1-abstract-full').style.display = 'none'; document.getElementById('1406.7350v1-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 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, including supplementary information</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 91, 195434 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1301.0778">arXiv:1301.0778</a> <span> [<a href="https://arxiv.org/pdf/1301.0778">pdf</a>, <a href="https://arxiv.org/ps/1301.0778">ps</a>, <a href="https://arxiv.org/format/1301.0778">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="Superconductivity">cond-mat.supr-con</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/ncomms2332">10.1038/ncomms2332 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ultrasensitive magnetic field detection using a single artificial atom </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bal%2C+M">Mustafa Bal</a>, <a href="/search/quant-ph?searchtype=author&query=Deng%2C+C">Chunqing Deng</a>, <a href="/search/quant-ph?searchtype=author&query=Orgiazzi%2C+J">Jean-Luc Orgiazzi</a>, <a href="/search/quant-ph?searchtype=author&query=Ong%2C+F">Florian Ong</a>, <a href="/search/quant-ph?searchtype=author&query=Lupascu%2C+A">Adrian Lupascu</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="1301.0778v1-abstract-short" style="display: inline;"> Efficient detection of magnetic fields is central to many areas of research and has important practical applications ranging from materials science to geomagnetism. High sensitivity detectors are commonly built using direct current-superconducting quantum interference devices (DC-SQUIDs) or atomic systems. Here we use a single artificial atom to implement an ultrahigh sensitivity magnetometer with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1301.0778v1-abstract-full').style.display = 'inline'; document.getElementById('1301.0778v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1301.0778v1-abstract-full" style="display: none;"> Efficient detection of magnetic fields is central to many areas of research and has important practical applications ranging from materials science to geomagnetism. High sensitivity detectors are commonly built using direct current-superconducting quantum interference devices (DC-SQUIDs) or atomic systems. Here we use a single artificial atom to implement an ultrahigh sensitivity magnetometer with a size in the micron range. The artificial atom is a superconducting two-level system at low temperatures, operated in a way similar to atomic magnetometry. The high sensitivity results from quantum coherence combined with strong coupling to magnetic field. By employing projective measurements, we obtain a sensitivity of $2.7\, \t{pT}/\sqrt{\t{Hz}}$ at 10 MHz. We discuss feasible improvements that will increase the sensitivity by over one order of magnitude. The intrinsic sensitivity of this method to AC fields in the 100 kHz - 10 MHz range compares favourably with DC-SQUIDs and atomic magnetometers of equivalent spatial resolution. This result illustrates the potential of artificial quantum systems for sensitive detection and related applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1301.0778v1-abstract-full').style.display = 'none'; document.getElementById('1301.0778v1-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 January, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Significantly revised and updated version of the manuscript is published in Nature Communications 3:1324 (2012)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat. Commun. 3:1324 doi: 10.1038/ncomms2332 (2012) </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

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