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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.13882">arXiv:2411.13882</a> <span> [<a href="https://arxiv.org/pdf/2411.13882">pdf</a>, <a href="https://arxiv.org/format/2411.13882">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A 2x2 quantum dot array in silicon with fully tuneable pairwise interdot coupling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Youn%2C+T">Tony Youn</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Yue Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Dickie%2C+A">Alexandra Dickie</a>, <a href="/search/quant-ph?searchtype=author&query=Yianni%2C+S">Steve Yianni</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/quant-ph?searchtype=author&query=Cifuentes%2C+J+D">Jes煤s D. Cifuentes</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.13882v1-abstract-short" style="display: inline;"> Recent advances in semiconductor spin qubits have achieved linear arrays exceeding ten qubits. Moving to two-dimensional (2D) qubit arrays is a critical next step to advance towards fault-tolerant implementations, but it poses substantial fabrication challenges, particularly because enabling control of nearest-neighbor entanglement requires the incorporation of interstitial exchange gates between… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.13882v1-abstract-full').style.display = 'inline'; document.getElementById('2411.13882v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.13882v1-abstract-full" style="display: none;"> Recent advances in semiconductor spin qubits have achieved linear arrays exceeding ten qubits. Moving to two-dimensional (2D) qubit arrays is a critical next step to advance towards fault-tolerant implementations, but it poses substantial fabrication challenges, particularly because enabling control of nearest-neighbor entanglement requires the incorporation of interstitial exchange gates between quantum dots in the qubit architecture. In this work, we present a 2D array of silicon metal-oxide-semiconductor (MOS) quantum dots with tunable interdot coupling between all adjacent dots. The device is characterized at 4.2 K, where we demonstrate the formation and isolation of double-dot and triple-dot configurations. We show control of all nearest-neighbor tunnel couplings spanning up to 30 decades per volt through the interstitial exchange gates and use advanced modeling tools to estimate the exchange interactions that could be realized among qubits in this architecture. These results represent a significant step towards the development of 2D MOS quantum processors compatible with foundry manufacturing techniques. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.13882v1-abstract-full').style.display = 'none'; document.getElementById('2411.13882v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.15590">arXiv:2410.15590</a> <span> [<a href="https://arxiv.org/pdf/2410.15590">pdf</a>, <a href="https://arxiv.org/format/2410.15590">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> A 300 mm foundry silicon spin qubit unit cell exceeding 99% fidelity in all operations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Steinacker%2C+P">Paul Steinacker</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Nickl%2C+A">Andreas Nickl</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Candido%2C+M">Marco Candido</a>, <a href="/search/quant-ph?searchtype=author&query=Cifuentes%2C+J+D">Jesus D. Cifuentes</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/quant-ph?searchtype=author&query=Kubicek%2C+S">Stefan Kubicek</a>, <a href="/search/quant-ph?searchtype=author&query=Jussot%2C+J">Julien Jussot</a>, <a href="/search/quant-ph?searchtype=author&query=Canvel%2C+Y">Yann Canvel</a>, <a href="/search/quant-ph?searchtype=author&query=Beyne%2C+S">Sofie Beyne</a>, <a href="/search/quant-ph?searchtype=author&query=Shimura%2C+Y">Yosuke Shimura</a>, <a href="/search/quant-ph?searchtype=author&query=Loo%2C+R">Roger Loo</a>, <a href="/search/quant-ph?searchtype=author&query=Godfrin%2C+C">Clement Godfrin</a>, <a href="/search/quant-ph?searchtype=author&query=Raes%2C+B">Bart Raes</a>, <a href="/search/quant-ph?searchtype=author&query=Baudot%2C+S">Sylvain Baudot</a>, <a href="/search/quant-ph?searchtype=author&query=Wan%2C+D">Danny Wan</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a> , et al. (2 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.15590v2-abstract-short" style="display: inline;"> Fabrication of quantum processors in advanced 300 mm wafer-scale complementary metal-oxide-semiconductor (CMOS) foundries provides a unique scaling pathway towards commercially viable quantum computing with potentially millions of qubits on a single chip. Here, we show precise qubit operation of a silicon two-qubit device made in a 300 mm semiconductor processing line. The key metrics including si… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15590v2-abstract-full').style.display = 'inline'; document.getElementById('2410.15590v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.15590v2-abstract-full" style="display: none;"> Fabrication of quantum processors in advanced 300 mm wafer-scale complementary metal-oxide-semiconductor (CMOS) foundries provides a unique scaling pathway towards commercially viable quantum computing with potentially millions of qubits on a single chip. Here, we show precise qubit operation of a silicon two-qubit device made in a 300 mm semiconductor processing line. The key metrics including single- and two-qubit control fidelities exceed 99% and state preparation and measurement fidelity exceeds 99.9%, as evidenced by gate set tomography (GST). We report coherence and lifetimes up to $T_\mathrm{2}^{\mathrm{*}} = 30.4$ $渭$s, $T_\mathrm{2}^{\mathrm{Hahn}} = 803$ $渭$s, and $T_1 = 6.3$ s. Crucially, the dominant operational errors originate from residual nuclear spin carrying isotopes, solvable with further isotopic purification, rather than charge noise arising from the dielectric environment. Our results answer the longstanding question whether the favourable properties including high-fidelity operation and long coherence times can be preserved when transitioning from a tailored academic to an industrial semiconductor fabrication technology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.15590v2-abstract-full').style.display = 'none'; document.getElementById('2410.15590v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 4 figures, 4 extended data figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.15778">arXiv:2407.15778</a> <span> [<a href="https://arxiv.org/pdf/2407.15778">pdf</a>, <a href="https://arxiv.org/format/2407.15778">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Violating Bell's inequality in gate-defined quantum dots </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Steinacker%2C+P">Paul Steinacker</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Vahapoglu%2C+E">Ensar Vahapoglu</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+R+Y">Rocky Y. Su</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Jones%2C+C">Cameron Jones</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Morello%2C+A">Andrea Morello</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</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="2407.15778v2-abstract-short" style="display: inline;"> Superior computational power promised by quantum computers utilises the fundamental quantum mechanical principle of entanglement. However, achieving entanglement and verifying that the generated state does not follow the principle of local causality has proven difficult for spin qubits in gate-defined quantum dots, as it requires simultaneously high concurrence values and readout fidelities to bre… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15778v2-abstract-full').style.display = 'inline'; document.getElementById('2407.15778v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.15778v2-abstract-full" style="display: none;"> Superior computational power promised by quantum computers utilises the fundamental quantum mechanical principle of entanglement. However, achieving entanglement and verifying that the generated state does not follow the principle of local causality has proven difficult for spin qubits in gate-defined quantum dots, as it requires simultaneously high concurrence values and readout fidelities to break the classical bound imposed by Bell's inequality. Here we employ heralded initialization and calibration via gate set tomography (GST), to reduce all relevant errors and push the fidelities of the full 2-qubit gate set above 99 %, including state preparation and measurement (SPAM). We demonstrate a 97.17 % Bell state fidelity without correcting for readout errors and violate Bell's inequality with a Bell signal of S = 2.731 close to the theoretical maximum of $2\sqrt{2}$. Our measurements exceed the classical limit even at elevated temperatures of 1.1 K or entanglement lifetimes of 100 $渭s$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15778v2-abstract-full').style.display = 'none'; document.getElementById('2407.15778v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">19 pages, 5 main figures, 9 extended data figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">MSC Class:</span> 81P68; 81-05 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2407.15151">arXiv:2407.15151</a> <span> [<a href="https://arxiv.org/pdf/2407.15151">pdf</a>, <a href="https://arxiv.org/format/2407.15151">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Spin Qubits with Scalable milli-kelvin CMOS Control </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Bartee%2C+S+K">Samuel K. Bartee</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Zuo%2C+K">Kun Zuo</a>, <a href="/search/quant-ph?searchtype=author&query=Das%2C+K">Kushal Das</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Pauka%2C+S+J">Sebastian J. Pauka</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+R+Y">Rocky Y. Su</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</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="2407.15151v1-abstract-short" style="display: inline;"> A key virtue of spin qubits is their sub-micron footprint, enabling a single silicon chip to host the millions of qubits required to execute useful quantum algorithms with error correction. With each physical qubit needing multiple control lines however, a fundamental barrier to scale is the extreme density of connections that bridge quantum devices to their external control and readout hardware.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15151v1-abstract-full').style.display = 'inline'; document.getElementById('2407.15151v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2407.15151v1-abstract-full" style="display: none;"> A key virtue of spin qubits is their sub-micron footprint, enabling a single silicon chip to host the millions of qubits required to execute useful quantum algorithms with error correction. With each physical qubit needing multiple control lines however, a fundamental barrier to scale is the extreme density of connections that bridge quantum devices to their external control and readout hardware. A promising solution is to co-locate the control system proximal to the qubit platform at milli-kelvin temperatures, wired-up via miniaturized interconnects. Even so, heat and crosstalk from closely integrated control have potential to degrade qubit performance, particularly for two-qubit entangling gates based on exchange coupling that are sensitive to electrical noise. Here, we benchmark silicon MOS-style electron spin qubits controlled via heterogeneously-integrated cryo-CMOS circuits with a low enough power density to enable scale-up. Demonstrating that cryo-CMOS can efficiently enable universal logic operations for spin qubits, we go on to show that mill-kelvin control has little impact on the performance of single- and two-qubit gates. Given the complexity of our milli-kelvin CMOS platform, with some 100-thousand transistors, these results open the prospect of scalable control based on the tight packaging of spin qubits with a chiplet style control architecture. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2407.15151v1-abstract-full').style.display = 'none'; document.getElementById('2407.15151v1-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2311.09567">arXiv:2311.09567</a> <span> [<a href="https://arxiv.org/pdf/2311.09567">pdf</a>, <a href="https://arxiv.org/format/2311.09567">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-024-52010-4">10.1038/s41467-024-52010-4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Entangling gates on degenerate spin qubits dressed by a global field </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Hansen%2C+I">Ingvild Hansen</a>, <a href="/search/quant-ph?searchtype=author&query=Seedhouse%2C+A+E">Amanda E. Seedhouse</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Nickl%2C+A">Andreas Nickl</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</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="2311.09567v2-abstract-short" style="display: inline;"> Coherently dressed spins have shown promising results as building blocks for future quantum computers owing to their resilience to environmental noise and their compatibility with global control fields. This mode of operation allows for more amenable qubit architecture requirements and simplifies signal routing on the chip. However, multi-qubit operations, such as qubit addressability and two-qubi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.09567v2-abstract-full').style.display = 'inline'; document.getElementById('2311.09567v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.09567v2-abstract-full" style="display: none;"> Coherently dressed spins have shown promising results as building blocks for future quantum computers owing to their resilience to environmental noise and their compatibility with global control fields. This mode of operation allows for more amenable qubit architecture requirements and simplifies signal routing on the chip. However, multi-qubit operations, such as qubit addressability and two-qubit gates, are yet to be demonstrated to establish global control in combination with dressed qubits as a viable path to universal quantum computing. Here we demonstrate simultaneous on-resonance driving of degenerate qubits using a global field while retaining addressability for qubits with equal Larmor frequencies. Furthermore, we implement SWAP oscillations during on-resonance driving, constituting the demonstration of driven two-qubit gates. Significantly, our findings highlight the fragility of entangling gates between superposition states and how dressing can increase the noise robustness. These results represent a crucial milestone towards global control operation with dressed qubits. It also opens a door to interesting spin physics on degenerate spins. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.09567v2-abstract-full').style.display = 'none'; document.getElementById('2311.09567v2-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 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 15, 7656 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.12542">arXiv:2309.12542</a> <span> [<a href="https://arxiv.org/pdf/2309.12542">pdf</a>, <a href="https://arxiv.org/format/2309.12542">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Spatio-temporal correlations of noise in MOS spin qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Seedhouse%2C+A+E">Amanda E. Seedhouse</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Yue Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2309.12542v2-abstract-short" style="display: inline;"> In quantum computing, characterising the full noise profile of qubits can aid the efforts towards increasing coherence times and fidelities by creating error mitigating techniques specific to the type of noise in the system, or by completely removing the sources of noise. Spin qubits in MOS quantum dots are exposed to noise originated from the complex glassy behaviour of two-level fluctuators, lea… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.12542v2-abstract-full').style.display = 'inline'; document.getElementById('2309.12542v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.12542v2-abstract-full" style="display: none;"> In quantum computing, characterising the full noise profile of qubits can aid the efforts towards increasing coherence times and fidelities by creating error mitigating techniques specific to the type of noise in the system, or by completely removing the sources of noise. Spin qubits in MOS quantum dots are exposed to noise originated from the complex glassy behaviour of two-level fluctuators, leading to non-trivial correlations between qubit properties both in space and time. With recent engineering progress, large amounts of data are being collected in typical spin qubit device experiments, and it is beneficiary to explore data analysis options inspired from fields of research that are experienced in managing large data sets, examples include astrophysics, finance and climate science. Here, we propose and demonstrate wavelet-based analysis techniques to decompose signals into both frequency and time components to gain a deeper insight into the sources of noise in our systems. We apply the analysis to a long feedback experiment performed on a state-of-the-art two-qubit system in a pair of SiMOS quantum dots. The observed correlations serve to identify common microscopic causes of noise, as well as to elucidate pathways for multi-qubit operation with a more scalable feedback system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.12542v2-abstract-full').style.display = 'none'; document.getElementById('2309.12542v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">updated reference</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.12541">arXiv:2309.12541</a> <span> [<a href="https://arxiv.org/pdf/2309.12541">pdf</a>, <a href="https://arxiv.org/format/2309.12541">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/5.0179958">10.1063/5.0179958 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Real-time feedback protocols for optimizing fault-tolerant two-qubit gate fidelities in a silicon spin system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Seedhouse%2C+A+E">Amanda E. Seedhouse</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Yue Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F">Fay Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2309.12541v1-abstract-short" style="display: inline;"> Recently, several groups have demonstrated two-qubit gate fidelities in semiconductor spin qubit systems above 99%. Achieving this regime of fault-tolerant compatible high fidelities is nontrivial and requires exquisite stability and precise control over the different qubit parameters over an extended period of time. This can be done by efficiently calibrating qubit control parameters against diff… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.12541v1-abstract-full').style.display = 'inline'; document.getElementById('2309.12541v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.12541v1-abstract-full" style="display: none;"> Recently, several groups have demonstrated two-qubit gate fidelities in semiconductor spin qubit systems above 99%. Achieving this regime of fault-tolerant compatible high fidelities is nontrivial and requires exquisite stability and precise control over the different qubit parameters over an extended period of time. This can be done by efficiently calibrating qubit control parameters against different sources of micro- and macroscopic noise. Here, we present several single- and two-qubit parameter feedback protocols, optimised for and implemented in state-of-the-art fast FPGA hardware. Furthermore, we use wavelet-based analysis on the collected feedback data to gain insight into the different sources of noise in the system. Scalable feedback is an outstanding challenge and the presented implementation and analysis gives insight into the benefits and drawbacks of qubit parameter feedback, as feedback related overhead increases. This work demonstrates a pathway towards robust qubit parameter feedback and systematic noise analysis, crucial for mitigation strategies towards systematic high-fidelity qubit operation compatible with quantum error correction protocols. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.12541v1-abstract-full').style.display = 'none'; document.getElementById('2309.12541v1-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 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Appl. Phys. Lett. 124, 114003 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.01849">arXiv:2309.01849</a> <span> [<a href="https://arxiv.org/pdf/2309.01849">pdf</a>, <a href="https://arxiv.org/format/2309.01849">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.110.125414">10.1103/PhysRevB.110.125414 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Impact of electrostatic crosstalk on spin qubits in dense CMOS quantum dot arrays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cifuentes%2C+J+D">Jesus D. Cifuentes</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Steinacker%2C+P">Paul Steinacker</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Hansen%2C+I">Ingvild Hansen</a>, <a href="/search/quant-ph?searchtype=author&query=Slack-Smith%2C+J+P">James P. Slack-Smith</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Vahapoglu%2C+E">Ensar Vahapoglu</a>, <a href="/search/quant-ph?searchtype=author&query=Leon%2C+R+C+C">Ross C. C. Leon</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K">Kohei Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Abrosimov%2C+N">Nikolay Abrosimov</a>, <a href="/search/quant-ph?searchtype=author&query=Pohl%2C+H">Hans-Joachim Pohl</a>, <a href="/search/quant-ph?searchtype=author&query=Thewalt%2C+M">Michael Thewalt</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Rahman%2C+R">Rajib Rahman</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2309.01849v1-abstract-short" style="display: inline;"> Quantum processors based on integrated nanoscale silicon spin qubits are a promising platform for highly scalable quantum computation. Current CMOS spin qubit processors consist of dense gate arrays to define the quantum dots, making them susceptible to crosstalk from capacitive coupling between a dot and its neighbouring gates. Small but sizeable spin-orbit interactions can transfer this electros… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.01849v1-abstract-full').style.display = 'inline'; document.getElementById('2309.01849v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.01849v1-abstract-full" style="display: none;"> Quantum processors based on integrated nanoscale silicon spin qubits are a promising platform for highly scalable quantum computation. Current CMOS spin qubit processors consist of dense gate arrays to define the quantum dots, making them susceptible to crosstalk from capacitive coupling between a dot and its neighbouring gates. Small but sizeable spin-orbit interactions can transfer this electrostatic crosstalk to the spin g-factors, creating a dependence of the Larmor frequency on the electric field created by gate electrodes positioned even tens of nanometers apart. By studying the Stark shift from tens of spin qubits measured in nine different CMOS devices, we developed a theoretical frawework that explains how electric fields couple to the spin of the electrons in increasingly complex arrays, including those electric fluctuations that limit qubit dephasing times $T_2^*$. The results will aid in the design of robust strategies to scale CMOS quantum technology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.01849v1-abstract-full').style.display = 'none'; document.getElementById('2309.01849v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">9 pages, 4 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.12626">arXiv:2308.12626</a> <span> [<a href="https://arxiv.org/pdf/2308.12626">pdf</a>, <a href="https://arxiv.org/format/2308.12626">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Methods for transverse and longitudinal spin-photon coupling in silicon quantum dots with intrinsic spin-orbit effect </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Guo%2C+K+S">Kevin S. Guo</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Chan%2C+K+W">Kok Wai Chan</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.12626v1-abstract-short" style="display: inline;"> In a full-scale quantum computer with a fault-tolerant architecture, having scalable, long-range interaction between qubits is expected to be a highly valuable resource. One promising method of achieving this is through the light-matter interaction between spins in semiconductors and photons in superconducting cavities. This paper examines the theory of both transverse and longitudinal spin-photon… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.12626v1-abstract-full').style.display = 'inline'; document.getElementById('2308.12626v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.12626v1-abstract-full" style="display: none;"> In a full-scale quantum computer with a fault-tolerant architecture, having scalable, long-range interaction between qubits is expected to be a highly valuable resource. One promising method of achieving this is through the light-matter interaction between spins in semiconductors and photons in superconducting cavities. This paper examines the theory of both transverse and longitudinal spin-photon coupling and their applications in the silicon metal-oxide-semiconductor (SiMOS) platform. We propose a method of coupling which uses the intrinsic spin-orbit interaction arising from orbital degeneracies in SiMOS qubits. Using theoretical analysis and experimental data, we show that the strong coupling regime is achievable in the transverse scheme. We also evaluate the feasibility of a longitudinal coupling driven by an AC modulation on the qubit. These coupling methods eschew the requirement for an external micromagnet, enhancing prospects for scalability and integration into a large-scale quantum computer. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.12626v1-abstract-full').style.display = 'none'; document.getElementById('2308.12626v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.02111">arXiv:2308.02111</a> <span> [<a href="https://arxiv.org/pdf/2308.02111">pdf</a>, <a href="https://arxiv.org/format/2308.02111">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/s41586-024-07160-2">10.1038/s41586-024-07160-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> High-fidelity operation and algorithmic initialisation of spin qubits above one kelvin </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+R+Y">Rocky Y. Su</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=van+Straaten%2C+B">Barnaby van Straaten</a>, <a href="/search/quant-ph?searchtype=author&query=Severin%2C+B">Brandon Severin</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Cifuentes%2C+J+D">Jesus D. Cifuentes</a>, <a href="/search/quant-ph?searchtype=author&query=Hansen%2C+I">Ingvild Hansen</a>, <a href="/search/quant-ph?searchtype=author&query=Seedhouse%2C+A+E">Amanda E. Seedhouse</a>, <a href="/search/quant-ph?searchtype=author&query=Vahapoglu%2C+E">Ensar Vahapoglu</a>, <a href="/search/quant-ph?searchtype=author&query=Abrosimov%2C+N+V">Nikolay V. Abrosimov</a>, <a href="/search/quant-ph?searchtype=author&query=Pohl%2C+H">Hans-Joachim Pohl</a>, <a href="/search/quant-ph?searchtype=author&query=Thewalt%2C+M+L+W">Michael L. W. Thewalt</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Ares%2C+N">Natalia Ares</a>, <a href="/search/quant-ph?searchtype=author&query=Bartlett%2C+S+D">Stephen D. Bartlett</a>, <a href="/search/quant-ph?searchtype=author&query=Morello%2C+A">Andrea Morello</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a> , et al. (1 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="2308.02111v2-abstract-short" style="display: inline;"> The encoding of qubits in semiconductor spin carriers has been recognised as a promising approach to a commercial quantum computer that can be lithographically produced and integrated at scale. However, the operation of the large number of qubits required for advantageous quantum applications will produce a thermal load exceeding the available cooling power of cryostats at millikelvin temperatures… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.02111v2-abstract-full').style.display = 'inline'; document.getElementById('2308.02111v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.02111v2-abstract-full" style="display: none;"> The encoding of qubits in semiconductor spin carriers has been recognised as a promising approach to a commercial quantum computer that can be lithographically produced and integrated at scale. However, the operation of the large number of qubits required for advantageous quantum applications will produce a thermal load exceeding the available cooling power of cryostats at millikelvin temperatures. As the scale-up accelerates, it becomes imperative to establish fault-tolerant operation above 1 kelvin, where the cooling power is orders of magnitude higher. Here, we tune up and operate spin qubits in silicon above 1 kelvin, with fidelities in the range required for fault-tolerant operation at such temperatures. We design an algorithmic initialisation protocol to prepare a pure two-qubit state even when the thermal energy is substantially above the qubit energies, and incorporate radio-frequency readout to achieve fidelities up to 99.34 per cent for both readout and initialisation. Importantly, we demonstrate a single-qubit Clifford gate fidelity of 99.85 per cent, and a two-qubit gate fidelity of 98.92 per cent. These advances overcome the fundamental limitation that the thermal energy must be well below the qubit energies for high-fidelity operation to be possible, surmounting a major obstacle in the pathway to scalable and fault-tolerant quantum computation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.02111v2-abstract-full').style.display = 'none'; document.getElementById('2308.02111v2-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 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 627, 772-777 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.12452">arXiv:2307.12452</a> <span> [<a href="https://arxiv.org/pdf/2307.12452">pdf</a>, <a href="https://arxiv.org/format/2307.12452">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Characterizing non-Markovian Quantum Process by Fast Bayesian Tomography </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Su%2C+R+Y">R. Y. Su</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">J. Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">N. Dumoulin. Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M+K">M. K. Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">W. Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Evans%2C+T+J">T. J. Evans</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">W. H. Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">F. E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+W">W. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Harper%2C+R">R. Harper</a>, <a href="/search/quant-ph?searchtype=author&query=Bartlett%2C+S+D">S. D. Bartlett</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">C. H. Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">A. Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">A. Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">T. Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2307.12452v2-abstract-short" style="display: inline;"> To push gate performance to levels beyond the thresholds for quantum error correction, it is important to characterize the error sources occurring on quantum gates. However, the characterization of non-Markovian error poses a challenge to current quantum process tomography techniques. Fast Bayesian Tomography (FBT) is a self-consistent gate set tomography protocol that can be bootstrapped from ear… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.12452v2-abstract-full').style.display = 'inline'; document.getElementById('2307.12452v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.12452v2-abstract-full" style="display: none;"> To push gate performance to levels beyond the thresholds for quantum error correction, it is important to characterize the error sources occurring on quantum gates. However, the characterization of non-Markovian error poses a challenge to current quantum process tomography techniques. Fast Bayesian Tomography (FBT) is a self-consistent gate set tomography protocol that can be bootstrapped from earlier characterization knowledge and be updated in real-time with arbitrary gate sequences. Here we demonstrate how FBT allows for the characterization of key non-Markovian error processes. We introduce two experimental protocols for FBT to diagnose the non-Markovian behavior of two-qubit systems on silicon quantum dots. To increase the efficiency and scalability of the experiment-analysis loop, we develop an online FBT software stack. To reduce experiment cost and analysis time, we also introduce a native readout method and warm boot strategy. Our results demonstrate that FBT is a useful tool for probing non-Markovian errors that can be detrimental to the ultimate realization of fault-tolerant operation on quantum computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.12452v2-abstract-full').style.display = 'none'; document.getElementById('2307.12452v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.07724">arXiv:2307.07724</a> <span> [<a href="https://arxiv.org/pdf/2307.07724">pdf</a>, <a href="https://arxiv.org/format/2307.07724">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PRXQuantum.5.010301">10.1103/PRXQuantum.5.010301 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Improved Single-Shot Qubit Readout Using Twin RF-SET Charge Correlations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Seedhouse%2C+A+E">Amanda E. Seedhouse</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Abrosimov%2C+N+V">Nikolay V. Abrosimov</a>, <a href="/search/quant-ph?searchtype=author&query=Pohl%2C+H">Hans-Joachim Pohl</a>, <a href="/search/quant-ph?searchtype=author&query=Thewalt%2C+M+L+W">Michael L. W. Thewalt</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2307.07724v1-abstract-short" style="display: inline;"> High fidelity qubit readout is critical in order to obtain the thresholds needed to implement quantum error correction protocols and achieve fault-tolerant quantum computing. Large-scale silicon qubit devices will have densely-packed arrays of quantum dots with multiple charge sensors that are, on average, farther away from the quantum dots, entailing a reduction in readout fidelities. Here, we pr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.07724v1-abstract-full').style.display = 'inline'; document.getElementById('2307.07724v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.07724v1-abstract-full" style="display: none;"> High fidelity qubit readout is critical in order to obtain the thresholds needed to implement quantum error correction protocols and achieve fault-tolerant quantum computing. Large-scale silicon qubit devices will have densely-packed arrays of quantum dots with multiple charge sensors that are, on average, farther away from the quantum dots, entailing a reduction in readout fidelities. Here, we present a readout technique that enhances the readout fidelity in a linear SiMOS 4-dot array by amplifying correlations between a pair of single-electron transistors, known as a twin SET. By recording and subsequently correlating the twin SET traces as we modulate the dot detuning across a charge transition, we demonstrate a reduction in the charge readout infidelity by over one order of magnitude compared to traditional readout methods. We also study the spin-to-charge conversion errors introduced by the modulation technique, and conclude that faster modulation frequencies avoid relaxation-induced errors without introducing significant spin flip errors, favouring the use of the technique at short integration times. This method not only allows for faster and higher fidelity qubit measurements, but it also enhances the signal corresponding to charge transitions that take place farther away from the sensors, enabling a way to circumvent the reduction in readout fidelities in large arrays of qubits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.07724v1-abstract-full').style.display = 'none'; document.getElementById('2307.07724v1-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 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PRX QUANTUM 5, 010301 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.14864">arXiv:2303.14864</a> <span> [<a href="https://arxiv.org/pdf/2303.14864">pdf</a>, <a href="https://arxiv.org/format/2303.14864">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="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-024-48557-x">10.1038/s41467-024-48557-x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Bounds to electron spin qubit variability for scalable CMOS architectures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Cifuentes%2C+J+D">Jes煤s D. Cifuentes</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Vahapoglu%2C+E">Ensar Vahapoglu</a>, <a href="/search/quant-ph?searchtype=author&query=Leon%2C+R+C+C">Ross C. C. Leon</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Otter%2C+D">Dennis Otter</a>, <a href="/search/quant-ph?searchtype=author&query=Dunmore%2C+D">Daniel Dunmore</a>, <a href="/search/quant-ph?searchtype=author&query=Mai%2C+P+Y">Philip Y. Mai</a>, <a href="/search/quant-ph?searchtype=author&query=Schlattner%2C+F">Fr茅d茅ric Schlattner</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K">Kohei Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Abrosimov%2C+N">Nikolay Abrosimov</a>, <a href="/search/quant-ph?searchtype=author&query=Pohl%2C+H">Hans-Joachim Pohl</a>, <a href="/search/quant-ph?searchtype=author&query=Thewalt%2C+M">Michael Thewalt</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Rahman%2C+R">Rajib Rahman</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.14864v3-abstract-short" style="display: inline;"> Spins of electrons in CMOS quantum dots combine exquisite quantum properties and scalable fabrication. In the age of quantum technology, however, the metrics that crowned Si/SiO2 as the microelectronics standard need to be reassessed with respect to their impact upon qubit performance. We chart the spin qubit variability due to the unavoidable atomic-scale roughness of the Si/SiO$_2$ interface, co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.14864v3-abstract-full').style.display = 'inline'; document.getElementById('2303.14864v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.14864v3-abstract-full" style="display: none;"> Spins of electrons in CMOS quantum dots combine exquisite quantum properties and scalable fabrication. In the age of quantum technology, however, the metrics that crowned Si/SiO2 as the microelectronics standard need to be reassessed with respect to their impact upon qubit performance. We chart the spin qubit variability due to the unavoidable atomic-scale roughness of the Si/SiO$_2$ interface, compiling experiments in 12 devices, and developing theoretical tools to analyse these results. Atomistic tight binding and path integral Monte Carlo methods are adapted for describing fluctuations in devices with millions of atoms by directly analysing their wavefunctions and electron paths instead of their energy spectra. We correlate the effect of roughness with the variability in qubit position, deformation, valley splitting, valley phase, spin-orbit coupling and exchange coupling. These variabilities are found to be bounded and lie within the tolerances for scalable architectures for quantum computing as long as robust control methods are incorporated. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.14864v3-abstract-full').style.display = 'none'; document.getElementById('2303.14864v3-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 8 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat Commun 15, 4299 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.04090">arXiv:2303.04090</a> <span> [<a href="https://arxiv.org/pdf/2303.04090">pdf</a>, <a href="https://arxiv.org/format/2303.04090">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-024-02614-w">10.1038/s41567-024-02614-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Assessment of error variation in high-fidelity two-qubit gates in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Stuyck%2C+N+D">Nard Dumoulin Stuyck</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+R+Y">Rocky Y. Su</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Cifuentes%2C+J+D">Jesus D. Cifuentes</a>, <a href="/search/quant-ph?searchtype=author&query=Seedhouse%2C+A+E">Amanda E. Seedhouse</a>, <a href="/search/quant-ph?searchtype=author&query=Seritan%2C+S+K">Stefan K. Seritan</a>, <a href="/search/quant-ph?searchtype=author&query=Ostrove%2C+C+I">Corey I. Ostrove</a>, <a href="/search/quant-ph?searchtype=author&query=Rudinger%2C+K+M">Kenneth M. Rudinger</a>, <a href="/search/quant-ph?searchtype=author&query=Leon%2C+R+C+C">Ross C. C. Leon</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+W">Wister Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Abrosimov%2C+N+V">Nikolay V. Abrosimov</a>, <a href="/search/quant-ph?searchtype=author&query=Pohl%2C+H">Hans-Joachim Pohl</a>, <a href="/search/quant-ph?searchtype=author&query=Thewalt%2C+M+L+W">Michael L. W. Thewalt</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Blume-Kohout%2C+R">Robin Blume-Kohout</a>, <a href="/search/quant-ph?searchtype=author&query=Bartlett%2C+S+D">Stephen D. Bartlett</a>, <a href="/search/quant-ph?searchtype=author&query=Morello%2C+A">Andrea Morello</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a> , et al. (2 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.04090v3-abstract-short" style="display: inline;"> Achieving high-fidelity entangling operations between qubits consistently is essential for the performance of multi-qubit systems and is a crucial factor in achieving fault-tolerant quantum processors. Solid-state platforms are particularly exposed to errors due to materials-induced variability between qubits, which leads to performance inconsistencies. Here we study the errors in a spin qubit pro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.04090v3-abstract-full').style.display = 'inline'; document.getElementById('2303.04090v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.04090v3-abstract-full" style="display: none;"> Achieving high-fidelity entangling operations between qubits consistently is essential for the performance of multi-qubit systems and is a crucial factor in achieving fault-tolerant quantum processors. Solid-state platforms are particularly exposed to errors due to materials-induced variability between qubits, which leads to performance inconsistencies. Here we study the errors in a spin qubit processor, tying them to their physical origins. We leverage this knowledge to demonstrate consistent and repeatable operation with above 99% fidelity of two-qubit gates in the technologically important silicon metal-oxide-semiconductor (SiMOS) quantum dot platform. We undertake a detailed study of these operations by analysing the physical errors and fidelities in multiple devices through numerous trials and extended periods to ensure that we capture the variation and the most common error types. Physical error sources include the slow nuclear and electrical noise on single qubits and contextual noise. The identification of the noise sources can be used to maintain performance within tolerance as well as inform future device fabrication. Furthermore, we investigate the impact of qubit design, feedback systems, and robust gates on implementing scalable, high-fidelity control strategies. These results are achieved by using three different characterization methods, we measure entangling gate fidelities ranging from 96.8% to 99.8%. Our analysis tools identify the causes of qubit degradation and offer ways understand their physical mechanisms. These results highlight both the capabilities and challenges for the scaling up of silicon spin-based qubits into full-scale quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.04090v3-abstract-full').style.display = 'none'; document.getElementById('2303.04090v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 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> Nat. Phys. 6 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.04724">arXiv:2208.04724</a> <span> [<a href="https://arxiv.org/pdf/2208.04724">pdf</a>, <a href="https://arxiv.org/format/2208.04724">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Chemical Physics">physics.chem-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1002/adma.202208557">10.1002/adma.202208557 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Jellybean quantum dots in silicon for qubit coupling and on-chip quantum chemistry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Wang%2C+Z">Zeheng Wang</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">William Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Leon%2C+R+C+C">Ross C. C. Leon</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Mai%2C+P">Philip Mai</a>, <a href="/search/quant-ph?searchtype=author&query=Liang%2C+D">Dylan Liang</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Su%2C+Y">Yue Su</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Morello%2C+A">Andrea Morello</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</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="2208.04724v1-abstract-short" style="display: inline;"> The small size and excellent integrability of silicon metal-oxide-semiconductor (SiMOS) quantum dot spin qubits make them an attractive system for mass-manufacturable, scaled-up quantum processors. Furthermore, classical control electronics can be integrated on-chip, in-between the qubits, if an architecture with sparse arrays of qubits is chosen. In such an architecture qubits are either transpor… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.04724v1-abstract-full').style.display = 'inline'; document.getElementById('2208.04724v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.04724v1-abstract-full" style="display: none;"> The small size and excellent integrability of silicon metal-oxide-semiconductor (SiMOS) quantum dot spin qubits make them an attractive system for mass-manufacturable, scaled-up quantum processors. Furthermore, classical control electronics can be integrated on-chip, in-between the qubits, if an architecture with sparse arrays of qubits is chosen. In such an architecture qubits are either transported across the chip via shuttling, or coupled via mediating quantum systems over short-to-intermediate distances. This paper investigates the charge and spin characteristics of an elongated quantum dot -- a so-called jellybean quantum dot -- for the prospects of acting as a qubit-qubit coupler. Charge transport, charge sensing and magneto-spectroscopy measurements are performed on a SiMOS quantum dot device at mK temperature, and compared to Hartree-Fock multi-electron simulations. At low electron occupancies where disorder effects and strong electron-electron interaction dominate over the electrostatic confinement potential, the data reveals the formation of three coupled dots, akin to a tunable, artificial molecule. One dot is formed centrally under the gate and two are formed at the edges. At high electron occupancies, these dots merge into one large dot with well-defined spin states, verifying that jellybean dots have the potential to be used as qubit couplers in future quantum computing architectures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.04724v1-abstract-full').style.display = 'none'; document.getElementById('2208.04724v1-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 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.06679">arXiv:2201.06679</a> <span> [<a href="https://arxiv.org/pdf/2201.06679">pdf</a>, <a href="https://arxiv.org/format/2201.06679">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41565-022-01280-4">10.1038/s41565-022-01280-4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On-demand electrical control of spin qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Gilbert%2C+W">Will Gilbert</a>, <a href="/search/quant-ph?searchtype=author&query=Tanttu%2C+T">Tuomo Tanttu</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Feng%2C+M">MengKe Feng</a>, <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Cifuentes%2C+J+D">Jesus D. Cifuentes</a>, <a href="/search/quant-ph?searchtype=author&query=Serrano%2C+S">Santiago Serrano</a>, <a href="/search/quant-ph?searchtype=author&query=Mai%2C+P+Y">Philip Y. Mai</a>, <a href="/search/quant-ph?searchtype=author&query=Leon%2C+R+C+C">Ross C. C. Leon</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Itoh%2C+K+M">Kohei M. Itoh</a>, <a href="/search/quant-ph?searchtype=author&query=Abrosimov%2C+N+V">Nikolay V. Abrosimov</a>, <a href="/search/quant-ph?searchtype=author&query=Pohl%2C+H">Hans-Joachim Pohl</a>, <a href="/search/quant-ph?searchtype=author&query=Thewalt%2C+M+L+W">Michael L. W. Thewalt</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Morello%2C+A">Andrea Morello</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2201.06679v2-abstract-short" style="display: inline;"> Once called a "classically non-describable two-valuedness" by Pauli , the electron spin is a natural resource for long-lived quantum information since it is mostly impervious to electric fluctuations and can be replicated in large arrays using silicon quantum dots, which offer high-fidelity control. Paradoxically, one of the most convenient control strategies is the integration of nanoscale magnet… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.06679v2-abstract-full').style.display = 'inline'; document.getElementById('2201.06679v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.06679v2-abstract-full" style="display: none;"> Once called a "classically non-describable two-valuedness" by Pauli , the electron spin is a natural resource for long-lived quantum information since it is mostly impervious to electric fluctuations and can be replicated in large arrays using silicon quantum dots, which offer high-fidelity control. Paradoxically, one of the most convenient control strategies is the integration of nanoscale magnets to artificially enhance the coupling between spins and electric field, which in turn hampers the spin's noise immunity and adds architectural complexity. Here we demonstrate a technique that enables a \emph{switchable} interaction between spins and orbital motion of electrons in silicon quantum dots, without the presence of a micromagnet. The naturally weak effects of the relativistic spin-orbit interaction in silicon are enhanced by more than three orders of magnitude by controlling the energy quantisation of electrons in the nanostructure, enhancing the orbital motion. Fast electrical control is demonstrated in multiple devices and electronic configurations, highlighting the utility of the technique. Using the electrical drive we achieve coherence time $T_{2,{\rm Hahn}}\approx50 渭$s, fast single-qubit gates with ${T_{蟺/2}=3}$ ns and gate fidelities of 99.93 % probed by randomised benchmarking. The higher gate speeds and better compatibility with CMOS manufacturing enabled by on-demand electric control improve the prospects for realising scalable silicon quantum processors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.06679v2-abstract-full').style.display = 'none'; document.getElementById('2201.06679v2-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 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Nanotechnology (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.13664">arXiv:2107.13664</a> <span> [<a href="https://arxiv.org/pdf/2107.13664">pdf</a>, <a href="https://arxiv.org/format/2107.13664">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> </div> <p class="title is-5 mathjax"> Materials for Silicon Quantum Dots and their Impact on Electron Spin Qubits </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2107.13664v2-abstract-short" style="display: inline;"> Quantum computers have the potential to efficiently solve problems in logistics, drug and material design, finance, and cybersecurity. However, millions of qubits will be necessary for correcting inevitable errors in quantum operations. In this scenario, electron spins in gate-defined silicon quantum dots are strong contenders for encoding qubits, leveraging the microelectronics industry know-how… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.13664v2-abstract-full').style.display = 'inline'; document.getElementById('2107.13664v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.13664v2-abstract-full" style="display: none;"> Quantum computers have the potential to efficiently solve problems in logistics, drug and material design, finance, and cybersecurity. However, millions of qubits will be necessary for correcting inevitable errors in quantum operations. In this scenario, electron spins in gate-defined silicon quantum dots are strong contenders for encoding qubits, leveraging the microelectronics industry know-how for fabricating densely populated chips with nanoscale electrodes. The sophisticated material combinations used in commercially manufactured transistors, however, will have a very different impact on the fragile qubits. We review here some key properties of the materials that have a direct impact on qubit performance and variability. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.13664v2-abstract-full').style.display = 'none'; document.getElementById('2107.13664v2-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> 29 July, 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">Comments:</span> <span class="has-text-grey-dark mathjax">Review paper</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.06433">arXiv:2103.06433</a> <span> [<a href="https://arxiv.org/pdf/2103.06433">pdf</a>, <a href="https://arxiv.org/format/2103.06433">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.nanolett.1c01003">10.1021/acs.nanolett.1c01003 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A high-sensitivity charge sensor for silicon qubits above one kelvin </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Huang%2C+J+Y">Jonathan Y. Huang</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Leon%2C+R+C+C">Ross C. C. Leon</a>, <a href="/search/quant-ph?searchtype=author&query=Yang%2C+C+H">Chih Hwan Yang</a>, <a href="/search/quant-ph?searchtype=author&query=Hudson%2C+F+E">Fay E. Hudson</a>, <a href="/search/quant-ph?searchtype=author&query=Escott%2C+C+C">Christopher C. Escott</a>, <a href="/search/quant-ph?searchtype=author&query=Saraiva%2C+A">Andre Saraiva</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Laucht%2C+A">Arne Laucht</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="2103.06433v2-abstract-short" style="display: inline;"> Recent studies of silicon spin qubits at temperatures above 1 K are encouraging demonstrations that the cooling requirements for solid-state quantum computing can be considerably relaxed. However, qubit readout mechanisms that rely on charge sensing with a single-island single-electron transistor (SISET) quickly lose sensitivity due to thermal broadening of the electron distribution in the reservo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.06433v2-abstract-full').style.display = 'inline'; document.getElementById('2103.06433v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.06433v2-abstract-full" style="display: none;"> Recent studies of silicon spin qubits at temperatures above 1 K are encouraging demonstrations that the cooling requirements for solid-state quantum computing can be considerably relaxed. However, qubit readout mechanisms that rely on charge sensing with a single-island single-electron transistor (SISET) quickly lose sensitivity due to thermal broadening of the electron distribution in the reservoirs. Here we exploit the tunneling between two quantised states in a double-island SET (DISET) to demonstrate a charge sensor with an improvement in signal-to-noise by an order of magnitude compared to a standard SISET, and a single-shot charge readout fidelity above 99 % up to 8 K at a bandwidth > 100 kHz. These improvements are consistent with our theoretical modelling of the temperature-dependent current transport for both types of SETs. With minor additional hardware overheads, these sensors can be integrated into existing qubit architectures for high fidelity charge readout at few-kelvin temperatures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.06433v2-abstract-full').style.display = 'none'; document.getElementById('2103.06433v2-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 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 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">Journal ref:</span> Nano Letters v12, 6328 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1305.4481">arXiv:1305.4481</a> <span> [<a href="https://arxiv.org/pdf/1305.4481">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nature11449">10.1038/nature11449 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A single-atom electron spin qubit in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Pla%2C+J+J">Jarryd J. Pla</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+K+Y">Kuan Y. Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Dehollain%2C+J+P">Juan P. Dehollain</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee H. Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Morton%2C+J+J+L">John J. L. Morton</a>, <a href="/search/quant-ph?searchtype=author&query=Jamieson%2C+D+N">David N. Jamieson</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Morello%2C+A">Andrea Morello</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1305.4481v1-abstract-short" style="display: inline;"> A single atom is the prototypical quantum system, and a natural candidate for a quantum bit - the elementary unit of a quantum computer. Atoms have been successfully used to store and process quantum information in electromagnetic traps, as well as in diamond through the use of the NV-center point defect. Solid state electrical devices possess great potential to scale up such demonstrations from f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1305.4481v1-abstract-full').style.display = 'inline'; document.getElementById('1305.4481v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1305.4481v1-abstract-full" style="display: none;"> A single atom is the prototypical quantum system, and a natural candidate for a quantum bit - the elementary unit of a quantum computer. Atoms have been successfully used to store and process quantum information in electromagnetic traps, as well as in diamond through the use of the NV-center point defect. Solid state electrical devices possess great potential to scale up such demonstrations from few-qubit control to larger scale quantum processors. In this direction, coherent control of spin qubits has been achieved in lithographically-defined double quantum dots in both GaAs and Si. However, it is a formidable challenge to combine the electrical measurement capabilities of engineered nanostructures with the benefits inherent to atomic spin qubits. Here we demonstrate the coherent manipulation of an individual electron spin qubit bound to a phosphorus donor atom in natural silicon, measured electrically via single-shot readout. We use electron spin resonance to drive Rabi oscillations, while a Hahn echo pulse sequence reveals a spin coherence time (T2) exceeding 200 渭s. This figure is expected to become even longer in isotopically enriched 28Si samples. Together with the use of a device architecture that is compatible with modern integrated circuit technology, these results indicate that the electron spin of a single phosphorus atom in silicon is an excellent platform on which to build a scalable quantum computer. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1305.4481v1-abstract-full').style.display = 'none'; document.getElementById('1305.4481v1-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 May, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 489, 541 (2012) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1304.3306">arXiv:1304.3306</a> <span> [<a href="https://arxiv.org/pdf/1304.3306">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.4802875">10.1063/1.4802875 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Printed Circuit Board Metal Powder Filters for Low Electron Temperatures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Mueller%2C+F">Filipp Mueller</a>, <a href="/search/quant-ph?searchtype=author&query=Schouten%2C+R+N">Raymond N. Schouten</a>, <a href="/search/quant-ph?searchtype=author&query=Brauns%2C+M">Matthias Brauns</a>, <a href="/search/quant-ph?searchtype=author&query=Gang%2C+T">Tian Gang</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee Han Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Lai%2C+N+S">Nai Shyan Lai</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=van+der+Wiel%2C+W+G">Wilfred G. van der Wiel</a>, <a href="/search/quant-ph?searchtype=author&query=Zwanenburg%2C+F+A">Floris A. Zwanenburg</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="1304.3306v2-abstract-short" style="display: inline;"> We report the characterisation of printed circuit boards (PCB) metal powder filters and their influence on the effective electron temperature which is as low as 22 mK for a quantum dot in a silicon MOSFET structure in a dilution refrigerator. We investigate the attenuation behaviour (10 MHz- 20 GHz) of filter made of four metal powders with a grain size below 50 um. The room-temperature attenuatio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1304.3306v2-abstract-full').style.display = 'inline'; document.getElementById('1304.3306v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1304.3306v2-abstract-full" style="display: none;"> We report the characterisation of printed circuit boards (PCB) metal powder filters and their influence on the effective electron temperature which is as low as 22 mK for a quantum dot in a silicon MOSFET structure in a dilution refrigerator. We investigate the attenuation behaviour (10 MHz- 20 GHz) of filter made of four metal powders with a grain size below 50 um. The room-temperature attenuation of a stainless steel powder filter is more than 80 dB at frequencies above 1.5 GHz. In all metal powder filters the attenuation increases with temperature. Compared to classical powder filters, the design presented here is much less laborious to fabricate and specifically the copper powder PCB-filters deliver an equal or even better performance than their classical counterparts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1304.3306v2-abstract-full').style.display = 'none'; document.getElementById('1304.3306v2-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 April, 2013; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 April, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 5 figures, accepted for publication in Rev. Sci. Instrum</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Rev. Sci. Instrum. 84, 044706 (2013) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1302.0047">arXiv:1302.0047</a> <span> [<a href="https://arxiv.org/pdf/1302.0047">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nature12011">10.1038/nature12011 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> High-fidelity readout and control of a nuclear spin qubit in silicon </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Pla%2C+J+J">Jarryd J. Pla</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+K+Y">Kuan Y. Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Dehollain%2C+J+P">Juan P. Dehollain</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">Wee H. Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Morton%2C+J+J+L">John J. L. Morton</a>, <a href="/search/quant-ph?searchtype=author&query=Zwanenburg%2C+F+A">Floris A. Zwanenburg</a>, <a href="/search/quant-ph?searchtype=author&query=Jamieson%2C+D+N">David N. Jamieson</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">Andrew S. Dzurak</a>, <a href="/search/quant-ph?searchtype=author&query=Morello%2C+A">Andrea Morello</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="1302.0047v1-abstract-short" style="display: inline;"> A single nuclear spin holds the promise of being a long-lived quantum bit or quantum memory, with the high fidelities required for fault-tolerant quantum computing. We show here that such promise could be fulfilled by a single phosphorus (31P) nuclear spin in a silicon nanostructure. By integrating single-shot readout of the electron spin with on-chip electron spin resonance, we demonstrate the qu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1302.0047v1-abstract-full').style.display = 'inline'; document.getElementById('1302.0047v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1302.0047v1-abstract-full" style="display: none;"> A single nuclear spin holds the promise of being a long-lived quantum bit or quantum memory, with the high fidelities required for fault-tolerant quantum computing. We show here that such promise could be fulfilled by a single phosphorus (31P) nuclear spin in a silicon nanostructure. By integrating single-shot readout of the electron spin with on-chip electron spin resonance, we demonstrate the quantum non-demolition, electrical single-shot readout of the nuclear spin, with readout fidelity better than 99.8% - the highest for any solid-state qubit. The single nuclear spin is then operated as a qubit by applying coherent radiofrequency (RF) pulses. For an ionized 31P donor we find a nuclear spin coherence time of 60 ms and a 1-qubit gate control fidelity exceeding 98%. These results demonstrate that the dominant technology of modern electronics can be adapted to host a complete electrical measurement and control platform for nuclear spin-based quantum information processing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1302.0047v1-abstract-full').style.display = 'none'; document.getElementById('1302.0047v1-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 January, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature 496, 334 (2013) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1103.5891">arXiv:1103.5891</a> <span> [<a href="https://arxiv.org/pdf/1103.5891">pdf</a>, <a href="https://arxiv.org/format/1103.5891">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.3593491">10.1063/1.3593491 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Single-electron shuttle based on a silicon quantum dot </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/quant-ph?searchtype=author&query=Chan%2C+K+W">K. W. Chan</a>, <a href="/search/quant-ph?searchtype=author&query=Mottonen%2C+M">M. Mottonen</a>, <a href="/search/quant-ph?searchtype=author&query=Kemppinen%2C+A">A. Kemppinen</a>, <a href="/search/quant-ph?searchtype=author&query=Lai%2C+N+S">N. S. Lai</a>, <a href="/search/quant-ph?searchtype=author&query=Tan%2C+K+Y">K. Y. Tan</a>, <a href="/search/quant-ph?searchtype=author&query=Lim%2C+W+H">W. H. Lim</a>, <a href="/search/quant-ph?searchtype=author&query=Dzurak%2C+A+S">A. S. Dzurak</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1103.5891v3-abstract-short" style="display: inline;"> We report on single-electron shuttling experiments with a silicon metal-oxide-semiconductor quantum dot at 300 mK. Our system consists of an accumulated electron layer at the Si/SiO_2 interface below an aluminum top gate with two additional barrier gates used to deplete the electron gas locally and to define a quantum dot. Directional single-electron shuttling from the source and to the drain lead… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1103.5891v3-abstract-full').style.display = 'inline'; document.getElementById('1103.5891v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1103.5891v3-abstract-full" style="display: none;"> We report on single-electron shuttling experiments with a silicon metal-oxide-semiconductor quantum dot at 300 mK. Our system consists of an accumulated electron layer at the Si/SiO_2 interface below an aluminum top gate with two additional barrier gates used to deplete the electron gas locally and to define a quantum dot. Directional single-electron shuttling from the source and to the drain lead is achieved by applying a dc source-drain bias while driving the barrier gates with an ac voltage of frequency f_p. Current plateaus at integer levels of ef_p are observed up to f_p = 240 MHz operation frequencies. The observed results are explained by a sequential tunneling model which suggests that the electron gas may be heated substantially by the ac driving voltage. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1103.5891v3-abstract-full').style.display = 'none'; document.getElementById('1103.5891v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 October, 2011; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 March, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2011. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Appl. Phys. Lett. 98, 212103 (2011) </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

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