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</div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.06557">arXiv:2410.06557</a> <span> [<a href="https://arxiv.org/pdf/2410.06557">pdf</a>, <a href="https://arxiv.org/format/2410.06557">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="Disordered Systems and Neural Networks">cond-mat.dis-nn</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> </div> </div> <p class="title is-5 mathjax"> Observation of disorder-free localization and efficient disorder averaging on a quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gyawali%2C+G">Gaurav Gyawali</a>, <a href="/search/quant-ph?searchtype=author&query=Cochran%2C+T">Tyler Cochran</a>, <a href="/search/quant-ph?searchtype=author&query=Lensky%2C+Y">Yuri Lensky</a>, <a href="/search/quant-ph?searchtype=author&query=Rosenberg%2C+E">Eliott Rosenberg</a>, <a href="/search/quant-ph?searchtype=author&query=Karamlou%2C+A+H">Amir H. Karamlou</a>, <a href="/search/quant-ph?searchtype=author&query=Kechedzhi%2C+K">Kostyantyn Kechedzhi</a>, <a href="/search/quant-ph?searchtype=author&query=Berndtsson%2C+J">Julia Berndtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">Abraham Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Abanin%2C+D">Dmitry Abanin</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Beni%2C+L+A">Laleh Aghababaie Beni</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">Markus Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Astrakhantsev%2C+N">Nikita Astrakhantsev</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Ballard%2C+B">Brian Ballard</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bilmes%2C+A">Alexander Bilmes</a>, <a href="/search/quant-ph?searchtype=author&query=Bortoli%2C+G">Gina Bortoli</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a> , et al. (195 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.06557v1-abstract-short" style="display: inline;"> One of the most challenging problems in the computational study of localization in quantum manybody systems is to capture the effects of rare events, which requires sampling over exponentially many disorder realizations. We implement an efficient procedure on a quantum processor, leveraging quantum parallelism, to efficiently sample over all disorder realizations. We observe localization without d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.06557v1-abstract-full').style.display = 'inline'; document.getElementById('2410.06557v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.06557v1-abstract-full" style="display: none;"> One of the most challenging problems in the computational study of localization in quantum manybody systems is to capture the effects of rare events, which requires sampling over exponentially many disorder realizations. We implement an efficient procedure on a quantum processor, leveraging quantum parallelism, to efficiently sample over all disorder realizations. We observe localization without disorder in quantum many-body dynamics in one and two dimensions: perturbations do not diffuse even though both the generator of evolution and the initial states are fully translationally invariant. The disorder strength as well as its density can be readily tuned using the initial state. Furthermore, we demonstrate the versatility of our platform by measuring Renyi entropies. Our method could also be extended to higher moments of the physical observables and disorder learning. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.06557v1-abstract-full').style.display = 'none'; document.getElementById('2410.06557v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.17142">arXiv:2409.17142</a> <span> [<a href="https://arxiv.org/pdf/2409.17142">pdf</a>, <a href="https://arxiv.org/format/2409.17142">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Lattice">hep-lat</span> </div> </div> <p class="title is-5 mathjax"> Visualizing Dynamics of Charges and Strings in (2+1)D Lattice Gauge Theories </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cochran%2C+T+A">Tyler A. Cochran</a>, <a href="/search/quant-ph?searchtype=author&query=Jobst%2C+B">Bernhard Jobst</a>, <a href="/search/quant-ph?searchtype=author&query=Rosenberg%2C+E">Eliott Rosenberg</a>, <a href="/search/quant-ph?searchtype=author&query=Lensky%2C+Y+D">Yuri D. Lensky</a>, <a href="/search/quant-ph?searchtype=author&query=Gyawali%2C+G">Gaurav Gyawali</a>, <a href="/search/quant-ph?searchtype=author&query=Eassa%2C+N">Norhan Eassa</a>, <a href="/search/quant-ph?searchtype=author&query=Will%2C+M">Melissa Will</a>, <a href="/search/quant-ph?searchtype=author&query=Abanin%2C+D">Dmitry Abanin</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Beni%2C+L+A">Laleh Aghababaie Beni</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">Markus Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">Abraham Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Ballard%2C+B">Brian Ballard</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bilmes%2C+A">Alexander Bilmes</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Bovaird%2C+J">Jenna Bovaird</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Browne%2C+D+A">David A. Browne</a> , et al. (167 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="2409.17142v1-abstract-short" style="display: inline;"> Lattice gauge theories (LGTs) can be employed to understand a wide range of phenomena, from elementary particle scattering in high-energy physics to effective descriptions of many-body interactions in materials. Studying dynamical properties of emergent phases can be challenging as it requires solving many-body problems that are generally beyond perturbative limits. We investigate the dynamics of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.17142v1-abstract-full').style.display = 'inline'; document.getElementById('2409.17142v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.17142v1-abstract-full" style="display: none;"> Lattice gauge theories (LGTs) can be employed to understand a wide range of phenomena, from elementary particle scattering in high-energy physics to effective descriptions of many-body interactions in materials. Studying dynamical properties of emergent phases can be challenging as it requires solving many-body problems that are generally beyond perturbative limits. We investigate the dynamics of local excitations in a $\mathbb{Z}_2$ LGT using a two-dimensional lattice of superconducting qubits. We first construct a simple variational circuit which prepares low-energy states that have a large overlap with the ground state; then we create particles with local gates and simulate their quantum dynamics via a discretized time evolution. As the effective magnetic field is increased, our measurements show signatures of transitioning from deconfined to confined dynamics. For confined excitations, the magnetic field induces a tension in the string connecting them. Our method allows us to experimentally image string dynamics in a (2+1)D LGT from which we uncover two distinct regimes inside the confining phase: for weak confinement the string fluctuates strongly in the transverse direction, while for strong confinement transverse fluctuations are effectively frozen. In addition, we demonstrate a resonance condition at which dynamical string breaking is facilitated. Our LGT implementation on a quantum processor presents a novel set of techniques for investigating emergent particle and string dynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.17142v1-abstract-full').style.display = 'none'; document.getElementById('2409.17142v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.13687">arXiv:2408.13687</a> <span> [<a href="https://arxiv.org/pdf/2408.13687">pdf</a>, <a href="https://arxiv.org/format/2408.13687">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Quantum error correction below the surface code threshold </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Aghababaie-Beni%2C+L">Laleh Aghababaie-Beni</a>, <a href="/search/quant-ph?searchtype=author&query=Aleiner%2C+I">Igor Aleiner</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">Markus Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">Abraham Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Astrakhantsev%2C+N">Nikita Astrakhantsev</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bacon%2C+D">Dave Bacon</a>, <a href="/search/quant-ph?searchtype=author&query=Ballard%2C+B">Brian Ballard</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bausch%2C+J">Johannes Bausch</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bilmes%2C+A">Alexander Bilmes</a>, <a href="/search/quant-ph?searchtype=author&query=Blackwell%2C+S">Sam Blackwell</a>, <a href="/search/quant-ph?searchtype=author&query=Boixo%2C+S">Sergio Boixo</a>, <a href="/search/quant-ph?searchtype=author&query=Bortoli%2C+G">Gina Bortoli</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Bovaird%2C+J">Jenna Bovaird</a>, <a href="/search/quant-ph?searchtype=author&query=Brill%2C+L">Leon Brill</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Browne%2C+D+A">David A. Browne</a> , et al. (224 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="2408.13687v1-abstract-short" style="display: inline;"> Quantum error correction provides a path to reach practical quantum computing by combining multiple physical qubits into a logical qubit, where the logical error rate is suppressed exponentially as more qubits are added. However, this exponential suppression only occurs if the physical error rate is below a critical threshold. In this work, we present two surface code memories operating below this… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.13687v1-abstract-full').style.display = 'inline'; document.getElementById('2408.13687v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.13687v1-abstract-full" style="display: none;"> Quantum error correction provides a path to reach practical quantum computing by combining multiple physical qubits into a logical qubit, where the logical error rate is suppressed exponentially as more qubits are added. However, this exponential suppression only occurs if the physical error rate is below a critical threshold. In this work, we present two surface code memories operating below this threshold: a distance-7 code and a distance-5 code integrated with a real-time decoder. The logical error rate of our larger quantum memory is suppressed by a factor of $螞$ = 2.14 $\pm$ 0.02 when increasing the code distance by two, culminating in a 101-qubit distance-7 code with 0.143% $\pm$ 0.003% error per cycle of error correction. This logical memory is also beyond break-even, exceeding its best physical qubit's lifetime by a factor of 2.4 $\pm$ 0.3. We maintain below-threshold performance when decoding in real time, achieving an average decoder latency of 63 $渭$s at distance-5 up to a million cycles, with a cycle time of 1.1 $渭$s. To probe the limits of our error-correction performance, we run repetition codes up to distance-29 and find that logical performance is limited by rare correlated error events occurring approximately once every hour, or 3 $\times$ 10$^9$ cycles. Our results present device performance that, if scaled, could realize the operational requirements of large scale fault-tolerant quantum algorithms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.13687v1-abstract-full').style.display = 'none'; document.getElementById('2408.13687v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 4 figures, Supplementary Information</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.17385">arXiv:2405.17385</a> <span> [<a href="https://arxiv.org/pdf/2405.17385">pdf</a>, <a href="https://arxiv.org/format/2405.17385">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Thermalization and Criticality on an Analog-Digital Quantum Simulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Astrakhantsev%2C+N">Nikita Astrakhantsev</a>, <a href="/search/quant-ph?searchtype=author&query=Karamlou%2C+A+H">Amir H. Karamlou</a>, <a href="/search/quant-ph?searchtype=author&query=Berndtsson%2C+J">Julia Berndtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Motruk%2C+J">Johannes Motruk</a>, <a href="/search/quant-ph?searchtype=author&query=Szasz%2C+A">Aaron Szasz</a>, <a href="/search/quant-ph?searchtype=author&query=Gross%2C+J+A">Jonathan A. Gross</a>, <a href="/search/quant-ph?searchtype=author&query=Schuckert%2C+A">Alexander Schuckert</a>, <a href="/search/quant-ph?searchtype=author&query=Westerhout%2C+T">Tom Westerhout</a>, <a href="/search/quant-ph?searchtype=author&query=Zhang%2C+Y">Yaxing Zhang</a>, <a href="/search/quant-ph?searchtype=author&query=Forati%2C+E">Ebrahim Forati</a>, <a href="/search/quant-ph?searchtype=author&query=Rossi%2C+D">Dario Rossi</a>, <a href="/search/quant-ph?searchtype=author&query=Kobrin%2C+B">Bryce Kobrin</a>, <a href="/search/quant-ph?searchtype=author&query=Di+Paolo%2C+A">Agustin Di Paolo</a>, <a href="/search/quant-ph?searchtype=author&query=Klots%2C+A+R">Andrey R. Klots</a>, <a href="/search/quant-ph?searchtype=author&query=Drozdov%2C+I">Ilya Drozdov</a>, <a href="/search/quant-ph?searchtype=author&query=Kurilovich%2C+V+D">Vladislav D. Kurilovich</a>, <a href="/search/quant-ph?searchtype=author&query=Petukhov%2C+A">Andre Petukhov</a>, <a href="/search/quant-ph?searchtype=author&query=Ioffe%2C+L+B">Lev B. Ioffe</a>, <a href="/search/quant-ph?searchtype=author&query=Elben%2C+A">Andreas Elben</a>, <a href="/search/quant-ph?searchtype=author&query=Rath%2C+A">Aniket Rath</a>, <a href="/search/quant-ph?searchtype=author&query=Vitale%2C+V">Vittorio Vitale</a>, <a href="/search/quant-ph?searchtype=author&query=Vermersch%2C+B">Benoit Vermersch</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Beni%2C+L+A">Laleh Aghababaie Beni</a> , et al. (202 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="2405.17385v2-abstract-short" style="display: inline;"> Understanding how interacting particles approach thermal equilibrium is a major challenge of quantum simulators. Unlocking the full potential of such systems toward this goal requires flexible initial state preparation, precise time evolution, and extensive probes for final state characterization. We present a quantum simulator comprising 69 superconducting qubits which supports both universal qua… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.17385v2-abstract-full').style.display = 'inline'; document.getElementById('2405.17385v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.17385v2-abstract-full" style="display: none;"> Understanding how interacting particles approach thermal equilibrium is a major challenge of quantum simulators. Unlocking the full potential of such systems toward this goal requires flexible initial state preparation, precise time evolution, and extensive probes for final state characterization. We present a quantum simulator comprising 69 superconducting qubits which supports both universal quantum gates and high-fidelity analog evolution, with performance beyond the reach of classical simulation in cross-entropy benchmarking experiments. Emulating a two-dimensional (2D) XY quantum magnet, we leverage a wide range of measurement techniques to study quantum states after ramps from an antiferromagnetic initial state. We observe signatures of the classical Kosterlitz-Thouless phase transition, as well as strong deviations from Kibble-Zurek scaling predictions attributed to the interplay between quantum and classical coarsening of the correlated domains. This interpretation is corroborated by injecting variable energy density into the initial state, which enables studying the effects of the eigenstate thermalization hypothesis (ETH) in targeted parts of the eigenspectrum. Finally, we digitally prepare the system in pairwise-entangled dimer states and image the transport of energy and vorticity during thermalization. These results establish the efficacy of superconducting analog-digital quantum processors for preparing states across many-body spectra and unveiling their thermalization dynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.17385v2-abstract-full').style.display = 'none'; document.getElementById('2405.17385v2-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> 8 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.17816">arXiv:2305.17816</a> <span> [<a href="https://arxiv.org/pdf/2305.17816">pdf</a>, <a href="https://arxiv.org/format/2305.17816">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> </div> </div> <p class="title is-5 mathjax"> Josephson parametric amplifier with Chebyshev gain profile and high saturation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Kaufman%2C+R">Ryan Kaufman</a>, <a href="/search/quant-ph?searchtype=author&query=White%2C+T">Theodore White</a>, <a href="/search/quant-ph?searchtype=author&query=Dykman%2C+M+I">Mark I. Dykman</a>, <a href="/search/quant-ph?searchtype=author&query=Iorio%2C+A">Andrea Iorio</a>, <a href="/search/quant-ph?searchtype=author&query=Stirling%2C+G">George Stirling</a>, <a href="/search/quant-ph?searchtype=author&query=Hong%2C+S">Sabrina Hong</a>, <a href="/search/quant-ph?searchtype=author&query=Opremcak%2C+A">Alex Opremcak</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Faoro%2C+L">Lara Faoro</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Burger%2C+T">Tim Burger</a>, <a href="/search/quant-ph?searchtype=author&query=Gasca%2C+R">Robert Gasca</a>, <a href="/search/quant-ph?searchtype=author&query=Naaman%2C+O">Ofer Naaman</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="2305.17816v1-abstract-short" style="display: inline;"> We demonstrate a Josephson parametric amplifier design with a band-pass impedance matching network based on a third-order Chebyshev prototype. We measured eight amplifiers operating at 4.6 GHz that exhibit gains of 20 dB with less than 1 dB gain ripple and up to 500 MHz bandwidth. The amplifiers further achieve high output saturation powers around -73 dBm based on the use of rf-SQUID arrays as the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.17816v1-abstract-full').style.display = 'inline'; document.getElementById('2305.17816v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.17816v1-abstract-full" style="display: none;"> We demonstrate a Josephson parametric amplifier design with a band-pass impedance matching network based on a third-order Chebyshev prototype. We measured eight amplifiers operating at 4.6 GHz that exhibit gains of 20 dB with less than 1 dB gain ripple and up to 500 MHz bandwidth. The amplifiers further achieve high output saturation powers around -73 dBm based on the use of rf-SQUID arrays as their nonlinear element. We characterize the system readout efficiency and its signal-to-noise ratio near saturation using a Sycamore processor, finding the data consistent with near quantum limited noise performance of the amplifiers. In addition, we measure the amplifiers' intermodulation distortion in two-tone experiments as a function of input power and inter-tone detuning, and observe excess distortion at small detuning with a pronounced dip as a function of signal power, which we interpret in terms of power-dependent dielectric losses. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.17816v1-abstract-full').style.display = 'none'; document.getElementById('2305.17816v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 10 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.13878">arXiv:2304.13878</a> <span> [<a href="https://arxiv.org/pdf/2304.13878">pdf</a>, <a href="https://arxiv.org/format/2304.13878">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/science.adh9932">10.1126/science.adh9932 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Stable Quantum-Correlated Many Body States through Engineered Dissipation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Mi%2C+X">X. Mi</a>, <a href="/search/quant-ph?searchtype=author&query=Michailidis%2C+A+A">A. A. Michailidis</a>, <a href="/search/quant-ph?searchtype=author&query=Shabani%2C+S">S. Shabani</a>, <a href="/search/quant-ph?searchtype=author&query=Miao%2C+K+C">K. C. Miao</a>, <a href="/search/quant-ph?searchtype=author&query=Klimov%2C+P+V">P. V. Klimov</a>, <a href="/search/quant-ph?searchtype=author&query=Lloyd%2C+J">J. Lloyd</a>, <a href="/search/quant-ph?searchtype=author&query=Rosenberg%2C+E">E. Rosenberg</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">R. Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Aleiner%2C+I">I. Aleiner</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">T. I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">M. Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">F. Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">K. Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">A. Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">J. Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">J. C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">A. Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bortoli%2C+G">G. Bortoli</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">A. Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Bovaird%2C+J">J. Bovaird</a>, <a href="/search/quant-ph?searchtype=author&query=Brill%2C+L">L. Brill</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">M. Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">B. B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">D. A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burger%2C+T">T. Burger</a> , et al. (142 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="2304.13878v2-abstract-short" style="display: inline;"> Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.13878v2-abstract-full').style.display = 'inline'; document.getElementById('2304.13878v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.13878v2-abstract-full" style="display: none;"> Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.13878v2-abstract-full').style.display = 'none'; document.getElementById('2304.13878v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 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> Science 383, 1332-1337 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.11119">arXiv:2304.11119</a> <span> [<a href="https://arxiv.org/pdf/2304.11119">pdf</a>, <a href="https://arxiv.org/format/2304.11119">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41586-024-07998-6">10.1038/s41586-024-07998-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Phase transition in Random Circuit Sampling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Morvan%2C+A">A. Morvan</a>, <a href="/search/quant-ph?searchtype=author&query=Villalonga%2C+B">B. Villalonga</a>, <a href="/search/quant-ph?searchtype=author&query=Mi%2C+X">X. Mi</a>, <a href="/search/quant-ph?searchtype=author&query=Mandr%C3%A0%2C+S">S. Mandr脿</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">A. Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Klimov%2C+P+V">P. V. Klimov</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Z. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Hong%2C+S">S. Hong</a>, <a href="/search/quant-ph?searchtype=author&query=Erickson%2C+C">C. Erickson</a>, <a href="/search/quant-ph?searchtype=author&query=Drozdov%2C+I+K">I. K. Drozdov</a>, <a href="/search/quant-ph?searchtype=author&query=Chau%2C+J">J. Chau</a>, <a href="/search/quant-ph?searchtype=author&query=Laun%2C+G">G. Laun</a>, <a href="/search/quant-ph?searchtype=author&query=Movassagh%2C+R">R. Movassagh</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">A. Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Brand%C3%A3o%2C+L+T+A+N">L. T. A. N. Brand茫o</a>, <a href="/search/quant-ph?searchtype=author&query=Peralta%2C+R">R. Peralta</a>, <a href="/search/quant-ph?searchtype=author&query=Abanin%2C+D">D. Abanin</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">R. Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Allen%2C+R">R. Allen</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">T. I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Anderson%2C+K">K. Anderson</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">M. Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">F. Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">K. Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">J. Atalaya</a> , et al. (160 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="2304.11119v2-abstract-short" style="display: inline;"> Undesired coupling to the surrounding environment destroys long-range correlations on quantum processors and hinders the coherent evolution in the nominally available computational space. This incoherent noise is an outstanding challenge to fully leverage the computation power of near-term quantum processors. It has been shown that benchmarking Random Circuit Sampling (RCS) with Cross-Entropy Benc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.11119v2-abstract-full').style.display = 'inline'; document.getElementById('2304.11119v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.11119v2-abstract-full" style="display: none;"> Undesired coupling to the surrounding environment destroys long-range correlations on quantum processors and hinders the coherent evolution in the nominally available computational space. This incoherent noise is an outstanding challenge to fully leverage the computation power of near-term quantum processors. It has been shown that benchmarking Random Circuit Sampling (RCS) with Cross-Entropy Benchmarking (XEB) can provide a reliable estimate of the effective size of the Hilbert space coherently available. The extent to which the presence of noise can trivialize the outputs of a given quantum algorithm, i.e. making it spoofable by a classical computation, is an unanswered question. Here, by implementing an RCS algorithm we demonstrate experimentally that there are two phase transitions observable with XEB, which we explain theoretically with a statistical model. The first is a dynamical transition as a function of the number of cycles and is the continuation of the anti-concentration point in the noiseless case. The second is a quantum phase transition controlled by the error per cycle; to identify it analytically and experimentally, we create a weak link model which allows varying the strength of noise versus coherent evolution. Furthermore, by presenting an RCS experiment with 67 qubits at 32 cycles, we demonstrate that the computational cost of our experiment is beyond the capabilities of existing classical supercomputers, even when accounting for the inevitable presence of noise. Our experimental and theoretical work establishes the existence of transitions to a stable computationally complex phase that is reachable with current quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.11119v2-abstract-full').style.display = 'none'; document.getElementById('2304.11119v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 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> Nature 634, 328-333 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.04792">arXiv:2303.04792</a> <span> [<a href="https://arxiv.org/pdf/2303.04792">pdf</a>, <a href="https://arxiv.org/format/2303.04792">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="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41586-023-06505-7">10.1038/s41586-023-06505-7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Measurement-induced entanglement and teleportation on a noisy quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hoke%2C+J+C">Jesse C. Hoke</a>, <a href="/search/quant-ph?searchtype=author&query=Ippoliti%2C+M">Matteo Ippoliti</a>, <a href="/search/quant-ph?searchtype=author&query=Rosenberg%2C+E">Eliott Rosenberg</a>, <a href="/search/quant-ph?searchtype=author&query=Abanin%2C+D">Dmitry Abanin</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">Markus Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">Abraham Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bortoli%2C+G">Gina Bortoli</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Bovaird%2C+J">Jenna Bovaird</a>, <a href="/search/quant-ph?searchtype=author&query=Brill%2C+L">Leon Brill</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burger%2C+T">Tim Burger</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">Nicholas Bushnell</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">Ben Chiaro</a> , et al. (138 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="2303.04792v2-abstract-short" style="display: inline;"> Measurement has a special role in quantum theory: by collapsing the wavefunction it can enable phenomena such as teleportation and thereby alter the "arrow of time" that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time that go beyond established paradigms for characterizing phases, either in or out… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.04792v2-abstract-full').style.display = 'inline'; document.getElementById('2303.04792v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.04792v2-abstract-full" style="display: none;"> Measurement has a special role in quantum theory: by collapsing the wavefunction it can enable phenomena such as teleportation and thereby alter the "arrow of time" that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time that go beyond established paradigms for characterizing phases, either in or out of equilibrium. On present-day NISQ processors, the experimental realization of this physics is challenging due to noise, hardware limitations, and the stochastic nature of quantum measurement. Here we address each of these experimental challenges and investigate measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping, to avoid mid-circuit measurement and access different manifestations of the underlying phases -- from entanglement scaling to measurement-induced teleportation -- in a unified way. We obtain finite-size signatures of a phase transition with a decoding protocol that correlates the experimental measurement record with classical simulation data. The phases display sharply different sensitivity to noise, which we exploit to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realize measurement-induced physics at scales that are at the limits of current NISQ processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.04792v2-abstract-full').style.display = 'none'; document.getElementById('2303.04792v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 622, 481-486 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.04728">arXiv:2211.04728</a> <span> [<a href="https://arxiv.org/pdf/2211.04728">pdf</a>, <a href="https://arxiv.org/format/2211.04728">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-023-02226-w">10.1038/s41567-023-02226-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Overcoming leakage in scalable quantum error correction </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Miao%2C+K+C">Kevin C. Miao</a>, <a href="/search/quant-ph?searchtype=author&query=McEwen%2C+M">Matt McEwen</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Kafri%2C+D">Dvir Kafri</a>, <a href="/search/quant-ph?searchtype=author&query=Pryadko%2C+L+P">Leonid P. Pryadko</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Opremcak%2C+A">Alex Opremcak</a>, <a href="/search/quant-ph?searchtype=author&query=Satzinger%2C+K+J">Kevin J. Satzinger</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Klimov%2C+P+V">Paul V. Klimov</a>, <a href="/search/quant-ph?searchtype=author&query=Quintana%2C+C">Chris Quintana</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Anderson%2C+K">Kyle Anderson</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">Markus Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">Abraham Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Bovaird%2C+J">Jenna Bovaird</a>, <a href="/search/quant-ph?searchtype=author&query=Brill%2C+L">Leon Brill</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burger%2C+T">Tim Burger</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a> , et al. (92 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="2211.04728v1-abstract-short" style="display: inline;"> Leakage of quantum information out of computational states into higher energy states represents a major challenge in the pursuit of quantum error correction (QEC). In a QEC circuit, leakage builds over time and spreads through multi-qubit interactions. This leads to correlated errors that degrade the exponential suppression of logical error with scale, challenging the feasibility of QEC as a path… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.04728v1-abstract-full').style.display = 'inline'; document.getElementById('2211.04728v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.04728v1-abstract-full" style="display: none;"> Leakage of quantum information out of computational states into higher energy states represents a major challenge in the pursuit of quantum error correction (QEC). In a QEC circuit, leakage builds over time and spreads through multi-qubit interactions. This leads to correlated errors that degrade the exponential suppression of logical error with scale, challenging the feasibility of QEC as a path towards fault-tolerant quantum computation. Here, we demonstrate the execution of a distance-3 surface code and distance-21 bit-flip code on a Sycamore quantum processor where leakage is removed from all qubits in each cycle. This shortens the lifetime of leakage and curtails its ability to spread and induce correlated errors. We report a ten-fold reduction in steady-state leakage population on the data qubits encoding the logical state and an average leakage population of less than $1 \times 10^{-3}$ throughout the entire device. The leakage removal process itself efficiently returns leakage population back to the computational basis, and adding it to a code circuit prevents leakage from inducing correlated error across cycles, restoring a fundamental assumption of QEC. With this demonstration that leakage can be contained, we resolve a key challenge for practical QEC at scale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.04728v1-abstract-full').style.display = 'none'; document.getElementById('2211.04728v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Main text: 7 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/2210.10799">arXiv:2210.10799</a> <span> [<a href="https://arxiv.org/pdf/2210.10799">pdf</a>, <a href="https://arxiv.org/format/2210.10799">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-023-02240-y">10.1038/s41567-023-02240-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Purification-based quantum error mitigation of pair-correlated electron simulations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=O%27Brien%2C+T+E">T. E. O'Brien</a>, <a href="/search/quant-ph?searchtype=author&query=Anselmetti%2C+G">G. Anselmetti</a>, <a href="/search/quant-ph?searchtype=author&query=Gkritsis%2C+F">F. Gkritsis</a>, <a href="/search/quant-ph?searchtype=author&query=Elfving%2C+V+E">V. E. Elfving</a>, <a href="/search/quant-ph?searchtype=author&query=Polla%2C+S">S. Polla</a>, <a href="/search/quant-ph?searchtype=author&query=Huggins%2C+W+J">W. J. Huggins</a>, <a href="/search/quant-ph?searchtype=author&query=Oumarou%2C+O">O. Oumarou</a>, <a href="/search/quant-ph?searchtype=author&query=Kechedzhi%2C+K">K. Kechedzhi</a>, <a href="/search/quant-ph?searchtype=author&query=Abanin%2C+D">D. Abanin</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">R. Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Aleiner%2C+I">I. Aleiner</a>, <a href="/search/quant-ph?searchtype=author&query=Allen%2C+R">R. Allen</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">T. I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Anderson%2C+K">K. Anderson</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">M. Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">F. Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">K. Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">A. Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">J. Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Bacon%2C+D">D. Bacon</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">J. C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">A. Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Boixo%2C+S">S. Boixo</a>, <a href="/search/quant-ph?searchtype=author&query=Bortoli%2C+G">G. Bortoli</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">A. Bourassa</a> , et al. (151 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2210.10799v1-abstract-short" style="display: inline;"> An important measure of the development of quantum computing platforms has been the simulation of increasingly complex physical systems. Prior to fault-tolerant quantum computing, robust error mitigation strategies are necessary to continue this growth. Here, we study physical simulation within the seniority-zero electron pairing subspace, which affords both a computational stepping stone to a ful… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.10799v1-abstract-full').style.display = 'inline'; document.getElementById('2210.10799v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.10799v1-abstract-full" style="display: none;"> An important measure of the development of quantum computing platforms has been the simulation of increasingly complex physical systems. Prior to fault-tolerant quantum computing, robust error mitigation strategies are necessary to continue this growth. Here, we study physical simulation within the seniority-zero electron pairing subspace, which affords both a computational stepping stone to a fully correlated model, and an opportunity to validate recently introduced ``purification-based'' error-mitigation strategies. We compare the performance of error mitigation based on doubling quantum resources in time (echo verification) or in space (virtual distillation), on up to $20$ qubits of a superconducting qubit quantum processor. We observe a reduction of error by one to two orders of magnitude below less sophisticated techniques (e.g. post-selection); the gain from error mitigation is seen to increase with the system size. Employing these error mitigation strategies enables the implementation of the largest variational algorithm for a correlated chemistry system to-date. Extrapolating performance from these results allows us to estimate minimum requirements for a beyond-classical simulation of electronic structure. We find that, despite the impressive gains from purification-based error mitigation, significant hardware improvements will be required for classically intractable variational chemistry simulations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.10799v1-abstract-full').style.display = 'none'; document.getElementById('2210.10799v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 13 page supplementary material, 12 figures. Experimental data available at https://doi.org/10.5281/zenodo.7225821</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat. Phys. (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.10255">arXiv:2210.10255</a> <span> [<a href="https://arxiv.org/pdf/2210.10255">pdf</a>, <a href="https://arxiv.org/format/2210.10255">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> </div> </div> <p class="title is-5 mathjax"> Non-Abelian braiding of graph vertices in a superconducting processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Lensky%2C+Y+D">Yuri D. Lensky</a>, <a href="/search/quant-ph?searchtype=author&query=Kechedzhi%2C+K">Kostyantyn Kechedzhi</a>, <a href="/search/quant-ph?searchtype=author&query=Drozdov%2C+I">Ilya Drozdov</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Hong%2C+S">Sabrina Hong</a>, <a href="/search/quant-ph?searchtype=author&query=Morvan%2C+A">Alexis Morvan</a>, <a href="/search/quant-ph?searchtype=author&query=Mi%2C+X">Xiao Mi</a>, <a href="/search/quant-ph?searchtype=author&query=Opremcak%2C+A">Alex Opremcak</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Allen%2C+R">Richard Allen</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">Markus Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">Abraham Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bacon%2C+D">Dave Bacon</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bortoli%2C+G">Gina Bortoli</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Bovaird%2C+J">Jenna Bovaird</a>, <a href="/search/quant-ph?searchtype=author&query=Brill%2C+L">Leon Brill</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a> , et al. (144 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2210.10255v2-abstract-short" style="display: inline;"> Indistinguishability of particles is a fundamental principle of quantum mechanics. For all elementary and quasiparticles observed to date - including fermions, bosons, and Abelian anyons - this principle guarantees that the braiding of identical particles leaves the system unchanged. However, in two spatial dimensions, an intriguing possibility exists: braiding of non-Abelian anyons causes rotatio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.10255v2-abstract-full').style.display = 'inline'; document.getElementById('2210.10255v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.10255v2-abstract-full" style="display: none;"> Indistinguishability of particles is a fundamental principle of quantum mechanics. For all elementary and quasiparticles observed to date - including fermions, bosons, and Abelian anyons - this principle guarantees that the braiding of identical particles leaves the system unchanged. However, in two spatial dimensions, an intriguing possibility exists: braiding of non-Abelian anyons causes rotations in a space of topologically degenerate wavefunctions. Hence, it can change the observables of the system without violating the principle of indistinguishability. Despite the well developed mathematical description of non-Abelian anyons and numerous theoretical proposals, the experimental observation of their exchange statistics has remained elusive for decades. Controllable many-body quantum states generated on quantum processors offer another path for exploring these fundamental phenomena. While efforts on conventional solid-state platforms typically involve Hamiltonian dynamics of quasi-particles, superconducting quantum processors allow for directly manipulating the many-body wavefunction via unitary gates. Building on predictions that stabilizer codes can host projective non-Abelian Ising anyons, we implement a generalized stabilizer code and unitary protocol to create and braid them. This allows us to experimentally verify the fusion rules of the anyons and braid them to realize their statistics. We then study the prospect of employing the anyons for quantum computation and utilize braiding to create an entangled state of anyons encoding three logical qubits. Our work provides new insights about non-Abelian braiding and - through the future inclusion of error correction to achieve topological protection - could open a path toward fault-tolerant quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.10255v2-abstract-full').style.display = 'none'; document.getElementById('2210.10255v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.07757">arXiv:2209.07757</a> <span> [<a href="https://arxiv.org/pdf/2209.07757">pdf</a>, <a href="https://arxiv.org/format/2209.07757">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/5.0127375">10.1063/5.0127375 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Readout of a quantum processor with high dynamic range Josephson parametric amplifiers </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=White%2C+T+C">T. C. White</a>, <a href="/search/quant-ph?searchtype=author&query=Opremcak%2C+A">Alex Opremcak</a>, <a href="/search/quant-ph?searchtype=author&query=Sterling%2C+G">George Sterling</a>, <a href="/search/quant-ph?searchtype=author&query=Korotkov%2C+A">Alexander Korotkov</a>, <a href="/search/quant-ph?searchtype=author&query=Sank%2C+D">Daniel Sank</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">Markus Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Bovaird%2C+J">Jenna Bovaird</a>, <a href="/search/quant-ph?searchtype=author&query=Brill%2C+L">Leon Brill</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burger%2C+T">Tim Burger</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">Nicholas Bushnell</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">Ben Chiaro</a>, <a href="/search/quant-ph?searchtype=author&query=Cogan%2C+J">Josh Cogan</a>, <a href="/search/quant-ph?searchtype=author&query=Collins%2C+R">Roberto Collins</a>, <a href="/search/quant-ph?searchtype=author&query=Crook%2C+A+L">Alexander L. Crook</a>, <a href="/search/quant-ph?searchtype=author&query=Curtin%2C+B">Ben Curtin</a> , et al. (69 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="2209.07757v2-abstract-short" style="display: inline;"> We demonstrate a high dynamic range Josephson parametric amplifier (JPA) in which the active nonlinear element is implemented using an array of rf-SQUIDs. The device is matched to the 50 $惟$ environment with a Klopfenstein-taper impedance transformer and achieves a bandwidth of 250-300 MHz, with input saturation powers up to -95 dBm at 20 dB gain. A 54-qubit Sycamore processor was used to benchmar… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.07757v2-abstract-full').style.display = 'inline'; document.getElementById('2209.07757v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.07757v2-abstract-full" style="display: none;"> We demonstrate a high dynamic range Josephson parametric amplifier (JPA) in which the active nonlinear element is implemented using an array of rf-SQUIDs. The device is matched to the 50 $惟$ environment with a Klopfenstein-taper impedance transformer and achieves a bandwidth of 250-300 MHz, with input saturation powers up to -95 dBm at 20 dB gain. A 54-qubit Sycamore processor was used to benchmark these devices, providing a calibration for readout power, an estimate of amplifier added noise, and a platform for comparison against standard impedance matched parametric amplifiers with a single dc-SQUID. We find that the high power rf-SQUID array design has no adverse effect on system noise, readout fidelity, or qubit dephasing, and we estimate an upper bound on amplifier added noise at 1.6 times the quantum limit. Lastly, amplifiers with this design show no degradation in readout fidelity due to gain compression, which can occur in multi-tone multiplexed readout with traditional JPAs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.07757v2-abstract-full').style.display = 'none'; document.getElementById('2209.07757v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 10 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Appl. Phys. Lett. 122, 014001 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.06431">arXiv:2207.06431</a> <span> [<a href="https://arxiv.org/pdf/2207.06431">pdf</a>, <a href="https://arxiv.org/format/2207.06431">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"> Suppressing quantum errors by scaling a surface code logical qubit </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Aleiner%2C+I">Igor Aleiner</a>, <a href="/search/quant-ph?searchtype=author&query=Allen%2C+R">Richard Allen</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Ansmann%2C+M">Markus Ansmann</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">Abraham Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bacon%2C+D">Dave Bacon</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Basso%2C+J">Joao Basso</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Boixo%2C+S">Sergio Boixo</a>, <a href="/search/quant-ph?searchtype=author&query=Bortoli%2C+G">Gina Bortoli</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Bovaird%2C+J">Jenna Bovaird</a>, <a href="/search/quant-ph?searchtype=author&query=Brill%2C+L">Leon Brill</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burger%2C+T">Tim Burger</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">Nicholas Bushnell</a> , et al. (132 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="2207.06431v2-abstract-short" style="display: inline;"> Practical quantum computing will require error rates that are well below what is achievable with physical qubits. Quantum error correction offers a path to algorithmically-relevant error rates by encoding logical qubits within many physical qubits, where increasing the number of physical qubits enhances protection against physical errors. However, introducing more qubits also increases the number… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.06431v2-abstract-full').style.display = 'inline'; document.getElementById('2207.06431v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.06431v2-abstract-full" style="display: none;"> Practical quantum computing will require error rates that are well below what is achievable with physical qubits. Quantum error correction offers a path to algorithmically-relevant error rates by encoding logical qubits within many physical qubits, where increasing the number of physical qubits enhances protection against physical errors. However, introducing more qubits also increases the number of error sources, so the density of errors must be sufficiently low in order for logical performance to improve with increasing code size. Here, we report the measurement of logical qubit performance scaling across multiple code sizes, and demonstrate that our system of superconducting qubits has sufficient performance to overcome the additional errors from increasing qubit number. We find our distance-5 surface code logical qubit modestly outperforms an ensemble of distance-3 logical qubits on average, both in terms of logical error probability over 25 cycles and logical error per cycle ($2.914\%\pm 0.016\%$ compared to $3.028\%\pm 0.023\%$). To investigate damaging, low-probability error sources, we run a distance-25 repetition code and observe a $1.7\times10^{-6}$ logical error per round floor set by a single high-energy event ($1.6\times10^{-7}$ when excluding this event). We are able to accurately model our experiment, and from this model we can extract error budgets that highlight the biggest challenges for future systems. These results mark the first experimental demonstration where quantum error correction begins to improve performance with increasing qubit number, illuminating the path to reaching the logical error rates required for computation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.06431v2-abstract-full').style.display = 'none'; document.getElementById('2207.06431v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Main text: 6 pages, 4 figures. v2: Update author list, references, Fig. S12, Table IV</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.05254">arXiv:2206.05254</a> <span> [<a href="https://arxiv.org/pdf/2206.05254">pdf</a>, <a href="https://arxiv.org/format/2206.05254">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41586-022-05348-y">10.1038/s41586-022-05348-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Formation of robust bound states of interacting microwave photons </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Morvan%2C+A">Alexis Morvan</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Mi%2C+X">Xiao Mi</a>, <a href="/search/quant-ph?searchtype=author&query=Neill%2C+C">Charles Neill</a>, <a href="/search/quant-ph?searchtype=author&query=Petukhov%2C+A">Andre Petukhov</a>, <a href="/search/quant-ph?searchtype=author&query=Kechedzhi%2C+K">Kostyantyn Kechedzhi</a>, <a href="/search/quant-ph?searchtype=author&query=Abanin%2C+D">Dmitry Abanin</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">Abraham Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bacon%2C+D">Dave Bacon</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Basso%2C+J">Joao Basso</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bortoli%2C+G">Gina Bortoli</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Bovaird%2C+J">Jenna Bovaird</a>, <a href="/search/quant-ph?searchtype=author&query=Brill%2C+L">Leon Brill</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burger%2C+T">Tim Burger</a> , et al. (125 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="2206.05254v3-abstract-short" style="display: inline;"> Systems of correlated particles appear in many fields of science and represent some of the most intractable puzzles in nature. The computational challenge in these systems arises when interactions become comparable to other energy scales, which makes the state of each particle depend on all other particles. The lack of general solutions for the 3-body problem and acceptable theory for strongly cor… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.05254v3-abstract-full').style.display = 'inline'; document.getElementById('2206.05254v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.05254v3-abstract-full" style="display: none;"> Systems of correlated particles appear in many fields of science and represent some of the most intractable puzzles in nature. The computational challenge in these systems arises when interactions become comparable to other energy scales, which makes the state of each particle depend on all other particles. The lack of general solutions for the 3-body problem and acceptable theory for strongly correlated electrons shows that our understanding of correlated systems fades when the particle number or the interaction strength increases. One of the hallmarks of interacting systems is the formation of multi-particle bound states. In a ring of 24 superconducting qubits, we develop a high fidelity parameterizable fSim gate that we use to implement the periodic quantum circuit of the spin-1/2 XXZ model, an archetypal model of interaction. By placing microwave photons in adjacent qubit sites, we study the propagation of these excitations and observe their bound nature for up to 5 photons. We devise a phase sensitive method for constructing the few-body spectrum of the bound states and extract their pseudo-charge by introducing a synthetic flux. By introducing interactions between the ring and additional qubits, we observe an unexpected resilience of the bound states to integrability breaking. This finding goes against the common wisdom that bound states in non-integrable systems are unstable when their energies overlap with the continuum spectrum. Our work provides experimental evidence for bound states of interacting photons and discovers their stability beyond the integrability limit. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.05254v3-abstract-full').style.display = 'none'; document.getElementById('2206.05254v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 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">7 pages + 15 pages supplements</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 612, 240-245 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.11372">arXiv:2204.11372</a> <span> [<a href="https://arxiv.org/pdf/2204.11372">pdf</a>, <a href="https://arxiv.org/format/2204.11372">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/science.abq5769">10.1126/science.abq5769 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Noise-resilient Edge Modes on a Chain of Superconducting Qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Mi%2C+X">Xiao Mi</a>, <a href="/search/quant-ph?searchtype=author&query=Sonner%2C+M">Michael Sonner</a>, <a href="/search/quant-ph?searchtype=author&query=Niu%2C+M+Y">Murphy Yuezhen Niu</a>, <a href="/search/quant-ph?searchtype=author&query=Lee%2C+K+W">Kenneth W. Lee</a>, <a href="/search/quant-ph?searchtype=author&query=Foxen%2C+B">Brooks Foxen</a>, <a href="/search/quant-ph?searchtype=author&query=Acharya%2C+R">Rajeev Acharya</a>, <a href="/search/quant-ph?searchtype=author&query=Aleiner%2C+I">Igor Aleiner</a>, <a href="/search/quant-ph?searchtype=author&query=Andersen%2C+T+I">Trond I. Andersen</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Asfaw%2C+A">Abraham Asfaw</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bacon%2C+D">Dave Bacon</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Basso%2C+J">Joao Basso</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bortoli%2C+G">Gina Bortoli</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Brill%2C+L">Leon Brill</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">Nicholas Bushnell</a> , et al. (103 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="2204.11372v2-abstract-short" style="display: inline;"> Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing its robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model which exhibits non-local Majorana edge modes (MEMs) with $\mathbb{Z}_2$ parity symmetry. Remarkably, we find that any multi-qub… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.11372v2-abstract-full').style.display = 'inline'; document.getElementById('2204.11372v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.11372v2-abstract-full" style="display: none;"> Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing its robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model which exhibits non-local Majorana edge modes (MEMs) with $\mathbb{Z}_2$ parity symmetry. Remarkably, we find that any multi-qubit Pauli operator overlapping with the MEMs exhibits a uniform late-time decay rate comparable to single-qubit relaxation rates, irrespective of its size or composition. This characteristic allows us to accurately reconstruct the exponentially localized spatial profiles of the MEMs. Furthermore, the MEMs are found to be resilient against certain symmetry-breaking noise owing to a prethermalization mechanism. Our work elucidates the complex interplay between noise and symmetry-protected edge modes in a solid-state environment. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.11372v2-abstract-full').style.display = 'none'; document.getElementById('2204.11372v2-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> 8 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 378, 785 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.13571">arXiv:2107.13571</a> <span> [<a href="https://arxiv.org/pdf/2107.13571">pdf</a>, <a href="https://arxiv.org/format/2107.13571">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="Disordered Systems and Neural Networks">cond-mat.dis-nn</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/10.1038/s41586-021-04257-w">10.1038/s41586-021-04257-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of Time-Crystalline Eigenstate Order on a Quantum Processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Mi%2C+X">Xiao Mi</a>, <a href="/search/quant-ph?searchtype=author&query=Ippoliti%2C+M">Matteo Ippoliti</a>, <a href="/search/quant-ph?searchtype=author&query=Quintana%2C+C">Chris Quintana</a>, <a href="/search/quant-ph?searchtype=author&query=Greene%2C+A">Ami Greene</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Gross%2C+J">Jonathan Gross</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Basso%2C+J">Joao Basso</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bilmes%2C+A">Alexander Bilmes</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Brill%2C+L">Leon Brill</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">Nicholas Bushnell</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">Benjamin Chiaro</a>, <a href="/search/quant-ph?searchtype=author&query=Collins%2C+R">Roberto Collins</a>, <a href="/search/quant-ph?searchtype=author&query=Courtney%2C+W">William Courtney</a>, <a href="/search/quant-ph?searchtype=author&query=Debroy%2C+D">Dripto Debroy</a> , et al. (80 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="2107.13571v2-abstract-short" style="display: inline;"> Quantum many-body systems display rich phase structure in their low-temperature equilibrium states. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC). Concretely, dyn… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.13571v2-abstract-full').style.display = 'inline'; document.getElementById('2107.13571v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.13571v2-abstract-full" style="display: none;"> Quantum many-body systems display rich phase structure in their low-temperature equilibrium states. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC). Concretely, dynamical phases can be defined in periodically driven many-body localized systems via the concept of eigenstate order. In eigenstate-ordered phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, wherein few select states can mask typical behavior. Here we implement a continuous family of tunable CPHASE gates on an array of superconducting qubits to experimentally observe an eigenstate-ordered DTC. We demonstrate the characteristic spatiotemporal response of a DTC for generic initial states. Our work employs a time-reversal protocol that discriminates external decoherence from intrinsic thermalization, and leverages quantum typicality to circumvent the exponential cost of densely sampling the eigenspectrum. In addition, we locate the phase transition out of the DTC with an experimental finite-size analysis. These results establish a scalable approach to study non-equilibrium phases of matter on current quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.13571v2-abstract-full').style.display = 'none'; document.getElementById('2107.13571v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 601, 531 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.05219">arXiv:2104.05219</a> <span> [<a href="https://arxiv.org/pdf/2104.05219">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-021-01432-8">10.1038/s41567-021-01432-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Resolving catastrophic error bursts from cosmic rays in large arrays of superconducting qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=McEwen%2C+M">Matt McEwen</a>, <a href="/search/quant-ph?searchtype=author&query=Faoro%2C+L">Lara Faoro</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Dunsworth%2C+A">Andrew Dunsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+T">Trent Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Kim%2C+S">Seon Kim</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Fowler%2C+A">Austin Fowler</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bilmes%2C+A">Alexander Bilmes</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">Nicholas Bushnell</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Collins%2C+R">Roberto Collins</a>, <a href="/search/quant-ph?searchtype=author&query=Demura%2C+S">Sean Demura</a>, <a href="/search/quant-ph?searchtype=author&query=Derk%2C+A+R">Alan R. Derk</a>, <a href="/search/quant-ph?searchtype=author&query=Erickson%2C+C">Catherine Erickson</a>, <a href="/search/quant-ph?searchtype=author&query=Giustina%2C+M">Marissa Giustina</a>, <a href="/search/quant-ph?searchtype=author&query=Harrington%2C+S+D">Sean D. Harrington</a>, <a href="/search/quant-ph?searchtype=author&query=Hong%2C+S">Sabrina Hong</a>, <a href="/search/quant-ph?searchtype=author&query=Jeffrey%2C+E">Evan Jeffrey</a>, <a href="/search/quant-ph?searchtype=author&query=Kelly%2C+J">Julian Kelly</a>, <a href="/search/quant-ph?searchtype=author&query=Klimov%2C+P+V">Paul V. Klimov</a> , et al. (28 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="2104.05219v1-abstract-short" style="display: inline;"> Scalable quantum computing can become a reality with error correction, provided coherent qubits can be constructed in large arrays. The key premise is that physical errors can remain both small and sufficiently uncorrelated as devices scale, so that logical error rates can be exponentially suppressed. However, energetic impacts from cosmic rays and latent radioactivity violate both of these assump… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.05219v1-abstract-full').style.display = 'inline'; document.getElementById('2104.05219v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.05219v1-abstract-full" style="display: none;"> Scalable quantum computing can become a reality with error correction, provided coherent qubits can be constructed in large arrays. The key premise is that physical errors can remain both small and sufficiently uncorrelated as devices scale, so that logical error rates can be exponentially suppressed. However, energetic impacts from cosmic rays and latent radioactivity violate both of these assumptions. An impinging particle ionizes the substrate, radiating high energy phonons that induce a burst of quasiparticles, destroying qubit coherence throughout the device. High-energy radiation has been identified as a source of error in pilot superconducting quantum devices, but lacking a measurement technique able to resolve a single event in detail, the effect on large scale algorithms and error correction in particular remains an open question. Elucidating the physics involved requires operating large numbers of qubits at the same rapid timescales as in error correction, exposing the event's evolution in time and spread in space. Here, we directly observe high-energy rays impacting a large-scale quantum processor. We introduce a rapid space and time-multiplexed measurement method and identify large bursts of quasiparticles that simultaneously and severely limit the energy coherence of all qubits, causing chip-wide failure. We track the events from their initial localised impact to high error rates across the chip. Our results provide direct insights into the scale and dynamics of these damaging error bursts in large-scale devices, and highlight the necessity of mitigation to enable quantum computing to scale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.05219v1-abstract-full').style.display = 'none'; document.getElementById('2104.05219v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Physics 18, 107-111 (Jan 2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.01180">arXiv:2104.01180</a> <span> [<a href="https://arxiv.org/pdf/2104.01180">pdf</a>, <a href="https://arxiv.org/format/2104.01180">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/10.1126/science.abi8378">10.1126/science.abi8378 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Realizing topologically ordered states on a quantum processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Satzinger%2C+K+J">K. J. Satzinger</a>, <a href="/search/quant-ph?searchtype=author&query=Liu%2C+Y">Y. Liu</a>, <a href="/search/quant-ph?searchtype=author&query=Smith%2C+A">A. Smith</a>, <a href="/search/quant-ph?searchtype=author&query=Knapp%2C+C">C. Knapp</a>, <a href="/search/quant-ph?searchtype=author&query=Newman%2C+M">M. Newman</a>, <a href="/search/quant-ph?searchtype=author&query=Jones%2C+C">C. Jones</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Z. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Quintana%2C+C">C. Quintana</a>, <a href="/search/quant-ph?searchtype=author&query=Mi%2C+X">X. Mi</a>, <a href="/search/quant-ph?searchtype=author&query=Dunsworth%2C+A">A. Dunsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Gidney%2C+C">C. Gidney</a>, <a href="/search/quant-ph?searchtype=author&query=Aleiner%2C+I">I. Aleiner</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">F. Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">K. Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">J. Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">R. Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">J. C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Barends%2C+R">R. Barends</a>, <a href="/search/quant-ph?searchtype=author&query=Basso%2C+J">J. Basso</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">A. Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bilmes%2C+A">A. Bilmes</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">M. Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">B. B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">D. A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">B. Burkett</a> , et al. (73 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="2104.01180v1-abstract-short" style="display: inline;"> The discovery of topological order has revolutionized the understanding of quantum matter in modern physics and provided the theoretical foundation for many quantum error correcting codes. Realizing topologically ordered states has proven to be extremely challenging in both condensed matter and synthetic quantum systems. Here, we prepare the ground state of the toric code Hamiltonian using an effi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.01180v1-abstract-full').style.display = 'inline'; document.getElementById('2104.01180v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.01180v1-abstract-full" style="display: none;"> The discovery of topological order has revolutionized the understanding of quantum matter in modern physics and provided the theoretical foundation for many quantum error correcting codes. Realizing topologically ordered states has proven to be extremely challenging in both condensed matter and synthetic quantum systems. Here, we prepare the ground state of the toric code Hamiltonian using an efficient quantum circuit on a superconducting quantum processor. We measure a topological entanglement entropy near the expected value of $\ln2$, and simulate anyon interferometry to extract the braiding statistics of the emergent excitations. Furthermore, we investigate key aspects of the surface code, including logical state injection and the decay of the non-local order parameter. Our results demonstrate the potential for quantum processors to provide key insights into topological quantum matter and quantum error correction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.01180v1-abstract-full').style.display = 'none'; document.getElementById('2104.01180v1-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">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages 4 figures, plus supplementary materials</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 374, 1237-1241 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.01491">arXiv:2103.01491</a> <span> [<a href="https://arxiv.org/pdf/2103.01491">pdf</a>, <a href="https://arxiv.org/format/2103.01491">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"> Cryogenic single-port calibration for superconducting microwave resonator measurements </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+H">Haozhi Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Singh%2C+S">S. Singh</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=Bardin%2C+J+C">J. C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Lin%2C+S+-">S. -X. Lin</a>, <a href="/search/quant-ph?searchtype=author&query=Messaoudi%2C+N">N. Messaoudi</a>, <a href="/search/quant-ph?searchtype=author&query=Castelli%2C+A+R">A. R. Castelli</a>, <a href="/search/quant-ph?searchtype=author&query=Rosen%2C+Y+J">Y. J. Rosen</a>, <a href="/search/quant-ph?searchtype=author&query=Holland%2C+E+T">E. T. Holland</a>, <a href="/search/quant-ph?searchtype=author&query=Pappas%2C+D+P">D. P. Pappas</a>, <a href="/search/quant-ph?searchtype=author&query=Mutus%2C+J+Y">J. Y. Mutus</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="2103.01491v1-abstract-short" style="display: inline;"> Superconducting circuit testing and materials loss characterization requires robust and reliable methods for the extraction of internal and coupling quality factors of microwave resonators. A common method, imposed by limitations on the device design or experimental configuration, is the single-port reflection geometry, i.e. reflection-mode. However, impedance mismatches in cryogenic systems must… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.01491v1-abstract-full').style.display = 'inline'; document.getElementById('2103.01491v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.01491v1-abstract-full" style="display: none;"> Superconducting circuit testing and materials loss characterization requires robust and reliable methods for the extraction of internal and coupling quality factors of microwave resonators. A common method, imposed by limitations on the device design or experimental configuration, is the single-port reflection geometry, i.e. reflection-mode. However, impedance mismatches in cryogenic systems must be accounted for through calibration of the measurement chain while it is at low temperatures. In this paper, we demonstrate a data-based, single-port calibration using commercial microwave standards and a vector network analyzer (VNA) with samples at millikelvin temperature in a dilution refrigerator, making this method useful for measurements of quantum phenomena. Finally, we cross reference our data-based, single-port calibration and reflection measurement with over-coupled 2D- and 3D-resonators against well established two-port techniques corroborating the validity of our method. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.01491v1-abstract-full').style.display = 'none'; document.getElementById('2103.01491v1-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 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 17 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/2102.06132">arXiv:2102.06132</a> <span> [<a href="https://arxiv.org/pdf/2102.06132">pdf</a>, <a href="https://arxiv.org/format/2102.06132">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41586-021-03588-y">10.1038/s41586-021-03588-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Exponential suppression of bit or phase flip errors with repetitive error correction </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Satzinger%2C+K+J">Kevin J. Satzinger</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Korotkov%2C+A+N">Alexander N. Korotkov</a>, <a href="/search/quant-ph?searchtype=author&query=Dunsworth%2C+A">Andrew Dunsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Sank%2C+D">Daniel Sank</a>, <a href="/search/quant-ph?searchtype=author&query=Quintana%2C+C">Chris Quintana</a>, <a href="/search/quant-ph?searchtype=author&query=McEwen%2C+M">Matt McEwen</a>, <a href="/search/quant-ph?searchtype=author&query=Barends%2C+R">Rami Barends</a>, <a href="/search/quant-ph?searchtype=author&query=Klimov%2C+P+V">Paul V. Klimov</a>, <a href="/search/quant-ph?searchtype=author&query=Hong%2C+S">Sabrina Hong</a>, <a href="/search/quant-ph?searchtype=author&query=Jones%2C+C">Cody Jones</a>, <a href="/search/quant-ph?searchtype=author&query=Petukhov%2C+A">Andre Petukhov</a>, <a href="/search/quant-ph?searchtype=author&query=Kafri%2C+D">Dvir Kafri</a>, <a href="/search/quant-ph?searchtype=author&query=Demura%2C+S">Sean Demura</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Gidney%2C+C">Craig Gidney</a>, <a href="/search/quant-ph?searchtype=author&query=Fowler%2C+A+G">Austin G. Fowler</a>, <a href="/search/quant-ph?searchtype=author&query=Putterman%2C+H">Harald Putterman</a>, <a href="/search/quant-ph?searchtype=author&query=Aleiner%2C+I">Igor Aleiner</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a> , et al. (66 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="2102.06132v1-abstract-short" style="display: inline;"> Realizing the potential of quantum computing will require achieving sufficiently low logical error rates. Many applications call for error rates in the $10^{-15}$ regime, but state-of-the-art quantum platforms typically have physical error rates near $10^{-3}$. Quantum error correction (QEC) promises to bridge this divide by distributing quantum logical information across many physical qubits so t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.06132v1-abstract-full').style.display = 'inline'; document.getElementById('2102.06132v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.06132v1-abstract-full" style="display: none;"> Realizing the potential of quantum computing will require achieving sufficiently low logical error rates. Many applications call for error rates in the $10^{-15}$ regime, but state-of-the-art quantum platforms typically have physical error rates near $10^{-3}$. Quantum error correction (QEC) promises to bridge this divide by distributing quantum logical information across many physical qubits so that errors can be detected and corrected. Logical errors are then exponentially suppressed as the number of physical qubits grows, provided that the physical error rates are below a certain threshold. QEC also requires that the errors are local and that performance is maintained over many rounds of error correction, two major outstanding experimental challenges. Here, we implement 1D repetition codes embedded in a 2D grid of superconducting qubits which demonstrate exponential suppression of bit or phase-flip errors, reducing logical error per round by more than $100\times$ when increasing the number of qubits from 5 to 21. Crucially, this error suppression is stable over 50 rounds of error correction. We also introduce a method for analyzing error correlations with high precision, and characterize the locality of errors in a device performing QEC for the first time. Finally, we perform error detection using a small 2D surface code logical qubit on the same device, and show that the results from both 1D and 2D codes agree with numerical simulations using a simple depolarizing error model. These findings demonstrate that superconducting qubits are on a viable path towards fault tolerant quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.06132v1-abstract-full').style.display = 'none'; document.getElementById('2102.06132v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature volume 595, pages 383-387 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.08870">arXiv:2101.08870</a> <span> [<a href="https://arxiv.org/pdf/2101.08870">pdf</a>, <a href="https://arxiv.org/format/2101.08870">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/science.abg5029">10.1126/science.abg5029 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Information Scrambling in Computationally Complex Quantum Circuits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Mi%2C+X">Xiao Mi</a>, <a href="/search/quant-ph?searchtype=author&query=Roushan%2C+P">Pedram Roushan</a>, <a href="/search/quant-ph?searchtype=author&query=Quintana%2C+C">Chris Quintana</a>, <a href="/search/quant-ph?searchtype=author&query=Mandra%2C+S">Salvatore Mandra</a>, <a href="/search/quant-ph?searchtype=author&query=Marshall%2C+J">Jeffrey Marshall</a>, <a href="/search/quant-ph?searchtype=author&query=Neill%2C+C">Charles Neill</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Barends%2C+R">Rami Barends</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Boixo%2C+S">Sergio Boixo</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">Alexandre Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">Nicholas Bushnell</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">Benjamin Chiaro</a>, <a href="/search/quant-ph?searchtype=author&query=Collins%2C+R">Roberto Collins</a>, <a href="/search/quant-ph?searchtype=author&query=Courtney%2C+W">William Courtney</a>, <a href="/search/quant-ph?searchtype=author&query=Demura%2C+S">Sean Demura</a> , et al. (68 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="2101.08870v1-abstract-short" style="display: inline;"> Interaction in quantum systems can spread initially localized quantum information into the many degrees of freedom of the entire system. Understanding this process, known as quantum scrambling, is the key to resolving various conundrums in physics. Here, by measuring the time-dependent evolution and fluctuation of out-of-time-order correlators, we experimentally investigate the dynamics of quantum… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.08870v1-abstract-full').style.display = 'inline'; document.getElementById('2101.08870v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.08870v1-abstract-full" style="display: none;"> Interaction in quantum systems can spread initially localized quantum information into the many degrees of freedom of the entire system. Understanding this process, known as quantum scrambling, is the key to resolving various conundrums in physics. Here, by measuring the time-dependent evolution and fluctuation of out-of-time-order correlators, we experimentally investigate the dynamics of quantum scrambling on a 53-qubit quantum processor. We engineer quantum circuits that distinguish the two mechanisms associated with quantum scrambling, operator spreading and operator entanglement, and experimentally observe their respective signatures. We show that while operator spreading is captured by an efficient classical model, operator entanglement requires exponentially scaled computational resources to simulate. These results open the path to studying complex and practically relevant physical observables with near-term quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.08870v1-abstract-full').style.display = 'none'; document.getElementById('2101.08870v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 374, 1479 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.00921">arXiv:2012.00921</a> <span> [<a href="https://arxiv.org/pdf/2012.00921">pdf</a>, <a href="https://arxiv.org/format/2012.00921">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41586-021-03576-2">10.1038/s41586-021-03576-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Accurately computing electronic properties of a quantum ring </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Neill%2C+C">C. Neill</a>, <a href="/search/quant-ph?searchtype=author&query=McCourt%2C+T">T. McCourt</a>, <a href="/search/quant-ph?searchtype=author&query=Mi%2C+X">X. Mi</a>, <a href="/search/quant-ph?searchtype=author&query=Jiang%2C+Z">Z. Jiang</a>, <a href="/search/quant-ph?searchtype=author&query=Niu%2C+M+Y">M. Y. Niu</a>, <a href="/search/quant-ph?searchtype=author&query=Mruczkiewicz%2C+W">W. Mruczkiewicz</a>, <a href="/search/quant-ph?searchtype=author&query=Aleiner%2C+I">I. Aleiner</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">F. Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">K. Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">J. Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">R. Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">J. C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Barends%2C+R">R. Barends</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">A. Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Bourassa%2C+A">A. Bourassa</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">M. Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">B. B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">D. A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">B. Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">N. Bushnell</a>, <a href="/search/quant-ph?searchtype=author&query=Campero%2C+J">J. Campero</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Z. Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">B. Chiaro</a>, <a href="/search/quant-ph?searchtype=author&query=Collins%2C+R">R. Collins</a>, <a href="/search/quant-ph?searchtype=author&query=Courtney%2C+W">W. Courtney</a> , et al. (67 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="2012.00921v2-abstract-short" style="display: inline;"> A promising approach to study condensed-matter systems is to simulate them on an engineered quantum platform. However, achieving the accuracy needed to outperform classical methods has been an outstanding challenge. Here, using eighteen superconducting qubits, we provide an experimental blueprint for an accurate condensed-matter simulator and demonstrate how to probe fundamental electronic propert… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.00921v2-abstract-full').style.display = 'inline'; document.getElementById('2012.00921v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.00921v2-abstract-full" style="display: none;"> A promising approach to study condensed-matter systems is to simulate them on an engineered quantum platform. However, achieving the accuracy needed to outperform classical methods has been an outstanding challenge. Here, using eighteen superconducting qubits, we provide an experimental blueprint for an accurate condensed-matter simulator and demonstrate how to probe fundamental electronic properties. We benchmark the underlying method by reconstructing the single-particle band-structure of a one-dimensional wire. We demonstrate nearly complete mitigation of decoherence and readout errors and arrive at an accuracy in measuring energy eigenvalues of this wire with an error of ~0.01 rad, whereas typical energy scales are of order 1 rad. Insight into this unprecedented algorithm fidelity is gained by highlighting robust properties of a Fourier transform, including the ability to resolve eigenenergies with a statistical uncertainty of 1e-4 rad. Furthermore, we synthesize magnetic flux and disordered local potentials, two key tenets of a condensed-matter system. When sweeping the magnetic flux, we observe avoided level crossings in the spectrum, a detailed fingerprint of the spatial distribution of local disorder. Combining these methods, we reconstruct electronic properties of the eigenstates where we observe persistent currents and a strong suppression of conductance with added disorder. Our work describes an accurate method for quantum simulation and paves the way to study novel quantum materials with superconducting qubits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.00921v2-abstract-full').style.display = 'none'; document.getElementById('2012.00921v2-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 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2011.01480">arXiv:2011.01480</a> <span> [<a href="https://arxiv.org/pdf/2011.01480">pdf</a>, <a href="https://arxiv.org/format/2011.01480">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Superconductivity">cond-mat.supr-con</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-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/10.1109/JMW.2020.3034071">10.1109/JMW.2020.3034071 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Microwaves in Quantum Computing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Slichter%2C+D+H">Daniel H. Slichter</a>, <a href="/search/quant-ph?searchtype=author&query=Reilly%2C+D+J">David J. Reilly</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2011.01480v1-abstract-short" style="display: inline;"> Quantum information processing systems rely on a broad range of microwave technologies and have spurred development of microwave devices and methods in new operating regimes. Here we review the use of microwave signals and systems in quantum computing, with specific reference to three leading quantum computing platforms: trapped atomic ion qubits, spin qubits in semiconductors, and superconducting… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.01480v1-abstract-full').style.display = 'inline'; document.getElementById('2011.01480v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2011.01480v1-abstract-full" style="display: none;"> Quantum information processing systems rely on a broad range of microwave technologies and have spurred development of microwave devices and methods in new operating regimes. Here we review the use of microwave signals and systems in quantum computing, with specific reference to three leading quantum computing platforms: trapped atomic ion qubits, spin qubits in semiconductors, and superconducting qubits. We highlight some key results and progress in quantum computing achieved through the use of microwave systems, and discuss how quantum computing applications have pushed the frontiers of microwave technology in some areas. We also describe open microwave engineering challenges for the construction of large-scale, fault-tolerant quantum computers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2011.01480v1-abstract-full').style.display = 'none'; document.getElementById('2011.01480v1-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 November, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Invited review article, to appear in IEEE Journal of Microwaves. 29 pages, 13 figures, $10^{6}$ to $10^{11}$ Hz</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> IEEE Journal of Microwaves 1, 403-427 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.07965">arXiv:2010.07965</a> <span> [<a href="https://arxiv.org/pdf/2010.07965">pdf</a>, <a href="https://arxiv.org/format/2010.07965">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"> Observation of separated dynamics of charge and spin in the Fermi-Hubbard model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bacon%2C+D">Dave Bacon</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Barends%2C+R">Rami Barends</a>, <a href="/search/quant-ph?searchtype=author&query=Bengtsson%2C+A">Andreas Bengtsson</a>, <a href="/search/quant-ph?searchtype=author&query=Boixo%2C+S">Sergio Boixo</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">Nicholas Bushnell</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu-An Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">Ben Chiaro</a>, <a href="/search/quant-ph?searchtype=author&query=Collins%2C+R">Roberto Collins</a>, <a href="/search/quant-ph?searchtype=author&query=Cotton%2C+S+J">Stephen J. Cotton</a>, <a href="/search/quant-ph?searchtype=author&query=Courtney%2C+W">William Courtney</a>, <a href="/search/quant-ph?searchtype=author&query=Demura%2C+S">Sean Demura</a>, <a href="/search/quant-ph?searchtype=author&query=Derk%2C+A">Alan Derk</a>, <a href="/search/quant-ph?searchtype=author&query=Dunsworth%2C+A">Andrew Dunsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Eppens%2C+D">Daniel Eppens</a>, <a href="/search/quant-ph?searchtype=author&query=Eckl%2C+T">Thomas Eckl</a> , et al. (74 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="2010.07965v1-abstract-short" style="display: inline;"> Strongly correlated quantum systems give rise to many exotic physical phenomena, including high-temperature superconductivity. Simulating these systems on quantum computers may avoid the prohibitively high computational cost incurred in classical approaches. However, systematic errors and decoherence effects presented in current quantum devices make it difficult to achieve this. Here, we simulate… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.07965v1-abstract-full').style.display = 'inline'; document.getElementById('2010.07965v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.07965v1-abstract-full" style="display: none;"> Strongly correlated quantum systems give rise to many exotic physical phenomena, including high-temperature superconductivity. Simulating these systems on quantum computers may avoid the prohibitively high computational cost incurred in classical approaches. However, systematic errors and decoherence effects presented in current quantum devices make it difficult to achieve this. Here, we simulate the dynamics of the one-dimensional Fermi-Hubbard model using 16 qubits on a digital superconducting quantum processor. We observe separations in the spreading velocities of charge and spin densities in the highly excited regime, a regime that is beyond the conventional quasiparticle picture. To minimize systematic errors, we introduce an accurate gate calibration procedure that is fast enough to capture temporal drifts of the gate parameters. We also employ a sequence of error-mitigation techniques to reduce decoherence effects and residual systematic errors. These procedures allow us to simulate the time evolution of the model faithfully despite having over 600 two-qubit gates in our circuits. Our experiment charts a path to practical quantum simulation of strongly correlated phenomena using available quantum devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.07965v1-abstract-full').style.display = 'none'; document.getElementById('2010.07965v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 15 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/2004.04197">arXiv:2004.04197</a> <span> [<a href="https://arxiv.org/pdf/2004.04197">pdf</a>, <a href="https://arxiv.org/format/2004.04197">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-020-01105-y">10.1038/s41567-020-01105-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum Approximate Optimization of Non-Planar Graph Problems on a Planar Superconducting Processor </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Harrigan%2C+M+P">Matthew P. Harrigan</a>, <a href="/search/quant-ph?searchtype=author&query=Sung%2C+K+J">Kevin J. Sung</a>, <a href="/search/quant-ph?searchtype=author&query=Neeley%2C+M">Matthew Neeley</a>, <a href="/search/quant-ph?searchtype=author&query=Satzinger%2C+K+J">Kevin J. Satzinger</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Atalaya%2C+J">Juan Atalaya</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Barends%2C+R">Rami Barends</a>, <a href="/search/quant-ph?searchtype=author&query=Boixo%2C+S">Sergio Boixo</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">Nicholas Bushnell</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">Ben Chiaro</a>, <a href="/search/quant-ph?searchtype=author&query=Collins%2C+R">Roberto Collins</a>, <a href="/search/quant-ph?searchtype=author&query=Courtney%2C+W">William Courtney</a>, <a href="/search/quant-ph?searchtype=author&query=Demura%2C+S">Sean Demura</a>, <a href="/search/quant-ph?searchtype=author&query=Dunsworth%2C+A">Andrew Dunsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Eppens%2C+D">Daniel Eppens</a>, <a href="/search/quant-ph?searchtype=author&query=Fowler%2C+A">Austin Fowler</a>, <a href="/search/quant-ph?searchtype=author&query=Foxen%2C+B">Brooks Foxen</a> , et al. (61 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="2004.04197v3-abstract-short" style="display: inline;"> We demonstrate the application of the Google Sycamore superconducting qubit quantum processor to combinatorial optimization problems with the quantum approximate optimization algorithm (QAOA). Like past QAOA experiments, we study performance for problems defined on the (planar) connectivity graph of our hardware; however, we also apply the QAOA to the Sherrington-Kirkpatrick model and MaxCut, both… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.04197v3-abstract-full').style.display = 'inline'; document.getElementById('2004.04197v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.04197v3-abstract-full" style="display: none;"> We demonstrate the application of the Google Sycamore superconducting qubit quantum processor to combinatorial optimization problems with the quantum approximate optimization algorithm (QAOA). Like past QAOA experiments, we study performance for problems defined on the (planar) connectivity graph of our hardware; however, we also apply the QAOA to the Sherrington-Kirkpatrick model and MaxCut, both high dimensional graph problems for which the QAOA requires significant compilation. Experimental scans of the QAOA energy landscape show good agreement with theory across even the largest instances studied (23 qubits) and we are able to perform variational optimization successfully. For problems defined on our hardware graph we obtain an approximation ratio that is independent of problem size and observe, for the first time, that performance increases with circuit depth. For problems requiring compilation, performance decreases with problem size but still provides an advantage over random guessing for circuits involving several thousand gates. This behavior highlights the challenge of using near-term quantum computers to optimize problems on graphs differing from hardware connectivity. As these graphs are more representative of real world instances, our results advocate for more emphasis on such problems in the developing tradition of using the QAOA as a holistic, device-level benchmark of quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.04197v3-abstract-full').style.display = 'none'; document.getElementById('2004.04197v3-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 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 15 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Physics 17, 332-336 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.04174">arXiv:2004.04174</a> <span> [<a href="https://arxiv.org/pdf/2004.04174">pdf</a>, <a href="https://arxiv.org/format/2004.04174">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="Chemical Physics">physics.chem-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/science.abb9811">10.1126/science.abb9811 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Hartree-Fock on a superconducting qubit quantum computer </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bacon%2C+D">Dave Bacon</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Barends%2C+R">Rami Barends</a>, <a href="/search/quant-ph?searchtype=author&query=Boixo%2C+S">Sergio Boixo</a>, <a href="/search/quant-ph?searchtype=author&query=Broughton%2C+M">Michael Broughton</a>, <a href="/search/quant-ph?searchtype=author&query=Buckley%2C+B+B">Bob B. Buckley</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Bushnell%2C+N">Nicholas Bushnell</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">Benjamin Chiaro</a>, <a href="/search/quant-ph?searchtype=author&query=Collins%2C+R">Roberto Collins</a>, <a href="/search/quant-ph?searchtype=author&query=Courtney%2C+W">William Courtney</a>, <a href="/search/quant-ph?searchtype=author&query=Demura%2C+S">Sean Demura</a>, <a href="/search/quant-ph?searchtype=author&query=Dunsworth%2C+A">Andrew Dunsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Eppens%2C+D">Daniel Eppens</a>, <a href="/search/quant-ph?searchtype=author&query=Farhi%2C+E">Edward Farhi</a>, <a href="/search/quant-ph?searchtype=author&query=Fowler%2C+A">Austin Fowler</a>, <a href="/search/quant-ph?searchtype=author&query=Foxen%2C+B">Brooks Foxen</a>, <a href="/search/quant-ph?searchtype=author&query=Gidney%2C+C">Craig Gidney</a>, <a href="/search/quant-ph?searchtype=author&query=Giustina%2C+M">Marissa Giustina</a> , et al. (57 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="2004.04174v4-abstract-short" style="display: inline;"> As the search continues for useful applications of noisy intermediate scale quantum devices, variational simulations of fermionic systems remain one of the most promising directions. Here, we perform a series of quantum simulations of chemistry the largest of which involved a dozen qubits, 78 two-qubit gates, and 114 one-qubit gates. We model the binding energy of ${\rm H}_6$, ${\rm H}_8$,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.04174v4-abstract-full').style.display = 'inline'; document.getElementById('2004.04174v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.04174v4-abstract-full" style="display: none;"> As the search continues for useful applications of noisy intermediate scale quantum devices, variational simulations of fermionic systems remain one of the most promising directions. Here, we perform a series of quantum simulations of chemistry the largest of which involved a dozen qubits, 78 two-qubit gates, and 114 one-qubit gates. We model the binding energy of ${\rm H}_6$, ${\rm H}_8$, ${\rm H}_{10}$ and ${\rm H}_{12}$ chains as well as the isomerization of diazene. We also demonstrate error-mitigation strategies based on $N$-representability which dramatically improve the effective fidelity of our experiments. Our parameterized ansatz circuits realize the Givens rotation approach to non-interacting fermion evolution, which we variationally optimize to prepare the Hartree-Fock wavefunction. This ubiquitous algorithmic primitive corresponds to a rotation of the orbital basis and is required by many proposals for correlated simulations of molecules and Hubbard models. Because non-interacting fermion evolutions are classically tractable to simulate, yet still generate highly entangled states over the computational basis, we use these experiments to benchmark the performance of our hardware while establishing a foundation for scaling up more complex correlated quantum simulations of chemistry. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.04174v4-abstract-full').style.display = 'none'; document.getElementById('2004.04174v4-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 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">updated link to experiment code, new version containing expanded data sets and corrected figure label</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 369 (6507), 1084-1089, 2020 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2001.08343">arXiv:2001.08343</a> <span> [<a href="https://arxiv.org/pdf/2001.08343">pdf</a>, <a href="https://arxiv.org/format/2001.08343">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.125.120504">10.1103/PhysRevLett.125.120504 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Demonstrating a Continuous Set of Two-qubit Gates for Near-term Quantum Algorithms </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Foxen%2C+B">B. Foxen</a>, <a href="/search/quant-ph?searchtype=author&query=Neill%2C+C">C. Neill</a>, <a href="/search/quant-ph?searchtype=author&query=Dunsworth%2C+A">A. Dunsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Roushan%2C+P">P. Roushan</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">B. Chiaro</a>, <a href="/search/quant-ph?searchtype=author&query=Megrant%2C+A">A. Megrant</a>, <a href="/search/quant-ph?searchtype=author&query=Kelly%2C+J">J. Kelly</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Satzinger%2C+K">K. Satzinger</a>, <a href="/search/quant-ph?searchtype=author&query=Barends%2C+R">R. Barends</a>, <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">F. Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">K. Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">R. Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bacon%2C+D">D. Bacon</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">J. C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Boixo%2C+S">S. Boixo</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D">D. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">B. Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Collins%2C+R">R. Collins</a>, <a href="/search/quant-ph?searchtype=author&query=Farhi%2C+E">E. Farhi</a>, <a href="/search/quant-ph?searchtype=author&query=Fowler%2C+A">A. Fowler</a>, <a href="/search/quant-ph?searchtype=author&query=Gidney%2C+C">C. Gidney</a>, <a href="/search/quant-ph?searchtype=author&query=Giustina%2C+M">M. Giustina</a>, <a href="/search/quant-ph?searchtype=author&query=Graff%2C+R">R. Graff</a> , et al. (32 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="2001.08343v2-abstract-short" style="display: inline;"> Quantum algorithms offer a dramatic speedup for computational problems in machine learning, material science, and chemistry. However, any near-term realizations of these algorithms will need to be heavily optimized to fit within the finite resources offered by existing noisy quantum hardware. Here, taking advantage of the strong adjustable coupling of gmon qubits, we demonstrate a continuous two-q… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.08343v2-abstract-full').style.display = 'inline'; document.getElementById('2001.08343v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2001.08343v2-abstract-full" style="display: none;"> Quantum algorithms offer a dramatic speedup for computational problems in machine learning, material science, and chemistry. However, any near-term realizations of these algorithms will need to be heavily optimized to fit within the finite resources offered by existing noisy quantum hardware. Here, taking advantage of the strong adjustable coupling of gmon qubits, we demonstrate a continuous two-qubit gate set that can provide a 3x reduction in circuit depth as compared to a standard decomposition. We implement two gate families: an iSWAP-like gate to attain an arbitrary swap angle, $胃$, and a CPHASE gate that generates an arbitrary conditional phase, $蠁$. Using one of each of these gates, we can perform an arbitrary two-qubit gate within the excitation-preserving subspace allowing for a complete implementation of the so-called Fermionic Simulation, or fSim, gate set. We benchmark the fidelity of the iSWAP-like and CPHASE gate families as well as 525 other fSim gates spread evenly across the entire fSim($胃$, $蠁$) parameter space achieving purity-limited average two-qubit Pauli error of $3.8 \times 10^{-3}$ per fSim gate. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2001.08343v2-abstract-full').style.display = 'none'; document.getElementById('2001.08343v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 17 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. 125, 120504 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1910.11333">arXiv:1910.11333</a> <span> [<a href="https://arxiv.org/pdf/1910.11333">pdf</a>, <a href="https://arxiv.org/format/1910.11333">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41586-019-1666-5">10.1038/s41586-019-1666-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Supplementary information for "Quantum supremacy using a programmable superconducting processor" </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Arute%2C+F">Frank Arute</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Babbush%2C+R">Ryan Babbush</a>, <a href="/search/quant-ph?searchtype=author&query=Bacon%2C+D">Dave Bacon</a>, <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C. Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Barends%2C+R">Rami Barends</a>, <a href="/search/quant-ph?searchtype=author&query=Biswas%2C+R">Rupak Biswas</a>, <a href="/search/quant-ph?searchtype=author&query=Boixo%2C+S">Sergio Boixo</a>, <a href="/search/quant-ph?searchtype=author&query=Brandao%2C+F+G+S+L">Fernando G. S. L. Brandao</a>, <a href="/search/quant-ph?searchtype=author&query=Buell%2C+D+A">David A. Buell</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Z">Zijun Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">Ben Chiaro</a>, <a href="/search/quant-ph?searchtype=author&query=Collins%2C+R">Roberto Collins</a>, <a href="/search/quant-ph?searchtype=author&query=Courtney%2C+W">William Courtney</a>, <a href="/search/quant-ph?searchtype=author&query=Dunsworth%2C+A">Andrew Dunsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Farhi%2C+E">Edward Farhi</a>, <a href="/search/quant-ph?searchtype=author&query=Foxen%2C+B">Brooks Foxen</a>, <a href="/search/quant-ph?searchtype=author&query=Fowler%2C+A">Austin Fowler</a>, <a href="/search/quant-ph?searchtype=author&query=Gidney%2C+C">Craig Gidney</a>, <a href="/search/quant-ph?searchtype=author&query=Giustina%2C+M">Marissa Giustina</a>, <a href="/search/quant-ph?searchtype=author&query=Graff%2C+R">Rob Graff</a>, <a href="/search/quant-ph?searchtype=author&query=Guerin%2C+K">Keith Guerin</a>, <a href="/search/quant-ph?searchtype=author&query=Habegger%2C+S">Steve Habegger</a> , et al. (52 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="1910.11333v2-abstract-short" style="display: inline;"> This is an updated version of supplementary information to accompany "Quantum supremacy using a programmable superconducting processor", an article published in the October 24, 2019 issue of Nature. The main article is freely available at https://www.nature.com/articles/s41586-019-1666-5. Summary of changes since arXiv:1910.11333v1 (submitted 23 Oct 2019): added URL for qFlex source code; added Er… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.11333v2-abstract-full').style.display = 'inline'; document.getElementById('1910.11333v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1910.11333v2-abstract-full" style="display: none;"> This is an updated version of supplementary information to accompany "Quantum supremacy using a programmable superconducting processor", an article published in the October 24, 2019 issue of Nature. The main article is freely available at https://www.nature.com/articles/s41586-019-1666-5. Summary of changes since arXiv:1910.11333v1 (submitted 23 Oct 2019): added URL for qFlex source code; added Erratum section; added Figure S41 comparing statistical and total uncertainty for log and linear XEB; new References [1,65]; miscellaneous updates for clarity and style consistency; miscellaneous typographical and formatting corrections. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1910.11333v2-abstract-full').style.display = 'none'; document.getElementById('1910.11333v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 October, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">67 pages, 51 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature, Vol 574, 505 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1902.10864">arXiv:1902.10864</a> <span> [<a href="https://arxiv.org/pdf/1902.10864">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1109/ISSCC.2019.8662480">10.1109/ISSCC.2019.8662480 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A 28nm Bulk-CMOS 4-to-8GHz <2mW Cryogenic Pulse Modulator for Scalable Quantum Computing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bardin%2C+J+C">Joseph C Bardin</a>, <a href="/search/quant-ph?searchtype=author&query=Jeffrey%2C+E">Evan Jeffrey</a>, <a href="/search/quant-ph?searchtype=author&query=Lucero%2C+E">Erik Lucero</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+T">Trent Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Naaman%2C+O">Ofer Naaman</a>, <a href="/search/quant-ph?searchtype=author&query=Barends%2C+R">Rami Barends</a>, <a href="/search/quant-ph?searchtype=author&query=White%2C+T">Ted White</a>, <a href="/search/quant-ph?searchtype=author&query=Giustina%2C+M">Marissa Giustina</a>, <a href="/search/quant-ph?searchtype=author&query=Sank%2C+D">Daniel Sank</a>, <a href="/search/quant-ph?searchtype=author&query=Roushan%2C+P">Pedram Roushan</a>, <a href="/search/quant-ph?searchtype=author&query=Arya%2C+K">Kunal Arya</a>, <a href="/search/quant-ph?searchtype=author&query=Chiaro%2C+B">Benjamin Chiaro</a>, <a href="/search/quant-ph?searchtype=author&query=Kelly%2C+J">Julian Kelly</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+J">Jimmy Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Burkett%2C+B">Brian Burkett</a>, <a href="/search/quant-ph?searchtype=author&query=Chen%2C+Y">Yu Chen</a>, <a href="/search/quant-ph?searchtype=author&query=Dunsworth%2C+A">Andrew Dunsworth</a>, <a href="/search/quant-ph?searchtype=author&query=Fowler%2C+A">Austin Fowler</a>, <a href="/search/quant-ph?searchtype=author&query=Foxen%2C+B">Brooks Foxen</a>, <a href="/search/quant-ph?searchtype=author&query=Gidney%2C+C">Craig Gidney</a>, <a href="/search/quant-ph?searchtype=author&query=Graff%2C+R">Rob Graff</a>, <a href="/search/quant-ph?searchtype=author&query=Klimov%2C+P">Paul Klimov</a>, <a href="/search/quant-ph?searchtype=author&query=Mutus%2C+J">Josh Mutus</a>, <a href="/search/quant-ph?searchtype=author&query=McEwen%2C+M">Matthew McEwen</a>, <a href="/search/quant-ph?searchtype=author&query=Megrant%2C+A">Anthony Megrant</a> , et al. (6 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="1902.10864v1-abstract-short" style="display: inline;"> Future quantum computing systems will require cryogenic integrated circuits to control and measure millions of qubits. In this paper, we report the design and characterization of a prototype cryogenic CMOS integrated circuit that has been optimized for the control of transmon qubits. The circuit has been integrated into a quantum measurement setup and its performance has been validated through mul… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.10864v1-abstract-full').style.display = 'inline'; document.getElementById('1902.10864v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1902.10864v1-abstract-full" style="display: none;"> Future quantum computing systems will require cryogenic integrated circuits to control and measure millions of qubits. In this paper, we report the design and characterization of a prototype cryogenic CMOS integrated circuit that has been optimized for the control of transmon qubits. The circuit has been integrated into a quantum measurement setup and its performance has been validated through multiple quantum control experiments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.10864v1-abstract-full').style.display = 'none'; document.getElementById('1902.10864v1-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 February, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 7 figures</span> </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> 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