npj Quantum Information最新文献_第7页

Steady-state dynamics and nonlocal correlations in thermoelectric Cooper pair splitters 热电库珀对分裂器的稳态动力学和非局域相关

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-08 DOI: 10.1038/s41534-025-00966-6

Arnav Arora, Siddhant Midha, Alexander Zyuzin, Pertti Hakonen, Bhaskaran Muralidharan

{"title":"Steady-state dynamics and nonlocal correlations in thermoelectric Cooper pair splitters","authors":"Arnav Arora, Siddhant Midha, Alexander Zyuzin, Pertti Hakonen, Bhaskaran Muralidharan","doi":"10.1038/s41534-025-00966-6","DOIUrl":"https://doi.org/10.1038/s41534-025-00966-6","url":null,"abstract":"Recent experiments on Cooper pair splitters using superconductor-quantum dot hybrids have embarked on creating entanglement in the solid-state, by engineering the sub-gap processes in the superconducting region. Using the thermoelectric Cooper pair splitter setup [Nat. Comm., 12, 21, (2021)] as a prototype, we present a comprehensive analysis of the fundamental components of the observed transport signal, aiming to critically clarify the operating regimes and confirm the nonlocal and nonclassical nature of correlations arising from crossed Andreev processes. By making a nexus with quantum discord, we identify operating points of nonlocal quantum correlations in the CPS device—information that cannot be extracted from the transport signal alone. A notable consequence of our analysis is the finding that contact-induced level broadening of the quantum dot’s discrete energy spectrum, along with its hybridization with the superconducting segment, can lead to shifted resonances in the crossed Andreev process as well as a parity reversal in the thermoelectric current. Our work thereby provides detailed insights into the gate voltage control of the quantum correlations in superconducting-hybrid Cooper pair splitters, revealing new avenues for harnessing quantum correlations in solid-state systems.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"12 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143575307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

To reset, or not to reset—that is the question 重启还是不重启，这是个问题

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-07 DOI: 10.1038/s41534-025-00998-y

György P. Gehér, Marcin Jastrzebski, Earl T. Campbell, Ophelia Crawford

{"title":"To reset, or not to reset—that is the question","authors":"György P. Gehér, Marcin Jastrzebski, Earl T. Campbell, Ophelia Crawford","doi":"10.1038/s41534-025-00998-y","DOIUrl":"https://doi.org/10.1038/s41534-025-00998-y","url":null,"abstract":"Whether to reset qubits, or not, during quantum error correction experiments is a question of both foundational and practical importance for quantum computing. Text-book quantum error correction demands that qubits are reset after measurement. However, fast qubit reset has proven challenging to execute at high fidelity. Consequently, many cutting-edge quantum error correction experiments are opting for the no-reset approach, where physical reset is not performed. It has recently been postulated that no-reset is functionally equivalent to reset procedures, as well as being faster and easier. For memory experiments, we confirm numerically that resetting provides no benefit. On the other hand, we identify a remarkable difference during logical operations. We find that unconditionally resetting qubits can reduce the duration of fault-tolerant logical operation by up to a factor of two as the number of measurement errors that can be tolerated is doubled. We support this with numerical simulations. However, our simulations also reveal that the no-reset performance is superior if the reset duration and infidelity exceed given thresholds. For example, with the noise model we considered, we find the no-reset performance to be superior when the reset duration is greater than approximately 100 ns and the physical error probability is greater than approximately 10−2.5 ≈ 0.003. Lastly, we introduce two novel syndrome extraction circuits that can reduce the time overhead of no-reset approaches. Our findings provide guidance on how experimentalists should design future experiments.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"67 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143570453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantum error mitigation in quantum annealing 量子退火中的量子误差缓解

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-06 DOI: 10.1038/s41534-025-00977-3

Jack Raymond, Mohammad H. Amin, Andrew D. King, Richard Harris, William Bernoudy, Andrew J. Berkley, Kelly Boothby, Anatoly Smirnov, Fabio Altomare, Michael Babcock, Catia Baron, Jake Connor, Martin H. Dehn, Colin Enderud, Emile Hoskinson, Shuiyuan Huang, Mark W. Johnson, Eric Ladizinsky, Trevor Lanting, Allison J. R. MacDonald, Gaelen Marsden, Reza Molavi, Travis Oh, Gabriel Poulin-Lamarre, Hugh Ramp, Chris Rich, Berta Trullas Clavera, Nicholas Tsai, Mark Volkmann, Jed D. Whittaker, Jason Yao, Niclas Heinsdorf, Nitin Kaushal, Alberto Nocera, Marcel Franz, Jacek Dziarmaga

{"title":"Quantum error mitigation in quantum annealing","authors":"Jack Raymond, Mohammad H. Amin, Andrew D. King, Richard Harris, William Bernoudy, Andrew J. Berkley, Kelly Boothby, Anatoly Smirnov, Fabio Altomare, Michael Babcock, Catia Baron, Jake Connor, Martin H. Dehn, Colin Enderud, Emile Hoskinson, Shuiyuan Huang, Mark W. Johnson, Eric Ladizinsky, Trevor Lanting, Allison J. R. MacDonald, Gaelen Marsden, Reza Molavi, Travis Oh, Gabriel Poulin-Lamarre, Hugh Ramp, Chris Rich, Berta Trullas Clavera, Nicholas Tsai, Mark Volkmann, Jed D. Whittaker, Jason Yao, Niclas Heinsdorf, Nitin Kaushal, Alberto Nocera, Marcel Franz, Jacek Dziarmaga","doi":"10.1038/s41534-025-00977-3","DOIUrl":"https://doi.org/10.1038/s41534-025-00977-3","url":null,"abstract":"Quantum error mitigation (QEM) presents a promising near-term approach to reducing errors when estimating expectation values in quantum computing. Here, we introduce QEM techniques tailored for quantum annealing, using zero-noise extrapolation (ZNE). We implement ZNE through zero-temperature and zero-time extrapolations. The practical zero-time extrapolation developed exploits the Kibble-Zurek mechanism so that only problem-Hamiltonian rescaling is required. We conduct experimental investigations into the quantum critical and post-critical dynamics of a transverse-field Ising spin chain by examining statistics with weak and strong post-critical dynamics. We demonstrate successful mitigation of thermal noise and non-thermal errors through both of these extrapolation techniques.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"16 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143560620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Boosted quantum teleportation 增强量子隐形传态

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-04 DOI: 10.1038/s41534-025-00992-4

Simone E. D’Aurelio, Matthias J. Bayerbach, Stefanie Barz

引用次数: 0

Quantum locking of intrinsic spin squeezed state in Earth-field-range magnetometry 地球磁场测量中本征自旋压缩态的量子锁定

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-03 DOI: 10.1038/s41534-025-00971-9

Peiyu Yang, Guzhi Bao, Jun Chen, Wei Du, Jinxian Guo, Weiping Zhang

{"title":"Quantum locking of intrinsic spin squeezed state in Earth-field-range magnetometry","authors":"Peiyu Yang, Guzhi Bao, Jun Chen, Wei Du, Jinxian Guo, Weiping Zhang","doi":"10.1038/s41534-025-00971-9","DOIUrl":"https://doi.org/10.1038/s41534-025-00971-9","url":null,"abstract":"In the Earth-field range, the nonlinear Zeeman (NLZ) effect has been a bottleneck limiting the sensitivity and accuracy of atomic magnetometry from physical mechanism. To break this bottleneck, various techniques are introduced to suppress the NLZ effect. Here we revisit the spin dynamics in the Earth-field-range magnetometry with the NLZ effect and identify the existence of the intrinsic spin squeezed state (SSS), generated from the coupling between nuclear and electron spins of each individual atom, with the oscillating squeezing degree and squeezing axis. Such oscillating features of the SSS prevent its direct observation and as well, accessibility to magnetic sensing. To exploit quantum advantage of the intrinsic SSS in the Earth-field-range magnetometry, it’s essential to lock the oscillating SSS to a persistent one. Hence we develop a quantum locking technique to achieve a persistent SSS, benefiting from which the sensitivity of the Earth-field-range magnetometer is quantum-enhanced. This work presents an innovative way turning the drawback of NLZ effect into the quantum advantage and opens a new access to quantum-enhanced magnetometry in the Earth-field range.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"5 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dimension reduction in quantum sampling of stochastic processes 随机过程量子采样中的降维问题

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-28 DOI: 10.1038/s41534-025-00978-2

Chengran Yang, Marta Florido-Llinàs, Mile Gu, Thomas J. Elliott

引用次数: 0

Calibrating quantum gates up to 52 qubits in a superconducting processor 在超导处理器中校准多达52个量子比特的量子门

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-26 DOI: 10.1038/s41534-025-00983-5

Daojin Fan, Guoding Liu, Shaowei Li, Ming Gong, Dachao Wu, Yiming Zhang, Chen Zha, Fusheng Chen, Sirui Cao, Yangsen Ye, Qingling Zhu, Chong Ying, Shaojun Guo, Haoran Qian, Yulin Wu, Hui Deng, Gang Wu, Cheng-Zhi Peng, Xiongfeng Ma, Xiaobo Zhu, Jian-Wei Pan

{"title":"Calibrating quantum gates up to 52 qubits in a superconducting processor","authors":"Daojin Fan, Guoding Liu, Shaowei Li, Ming Gong, Dachao Wu, Yiming Zhang, Chen Zha, Fusheng Chen, Sirui Cao, Yangsen Ye, Qingling Zhu, Chong Ying, Shaojun Guo, Haoran Qian, Yulin Wu, Hui Deng, Gang Wu, Cheng-Zhi Peng, Xiongfeng Ma, Xiaobo Zhu, Jian-Wei Pan","doi":"10.1038/s41534-025-00983-5","DOIUrl":"https://doi.org/10.1038/s41534-025-00983-5","url":null,"abstract":"Benchmarking large-scale quantum gates, typically involving multiple native two-qubit and single-qubit gates, is crucial in quantum computing. Global fidelity, encompassing information about inter-gate correlations, offers a comprehensive metric for evaluating and optimizing gate performance, unlike the fidelities of individual local native gates. In this work, utilizing the character-average benchmarking protocol implementable in a shallow circuit, we successfully benchmark gate fidelities up to 52 qubits. Notably, we achieved a fidelity of 63.09% ± 0.23% for a 44-qubit parallel CZ gate. Utilizing the global fidelity of the parallel CZ gate, we explore the correlations among local CZ gates by introducing an inter-gate correlation metric, enabling one to simultaneously quantify crosstalk error when benchmarking gate fidelity. Finally, we apply our methods in gate optimization. By leveraging global fidelity for optimization, we enhance the fidelity of a 6-qubit parallel CZ gate from 87.65% to 92.04% and decrease the gate correlation from 3.53% to 3.22%, compared to local gate fidelity-based optimization. The experimental results align well with our established composite noise model, incorporating depolarizing and ZZ-coupling noises, and provide valuable insight into further study and mitigation of correlated noise.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"24 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143495518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Parameterized quantum comb and simpler circuits for reversing unknown qubit-unitary operations 参数化量子梳和逆转未知量子位酉运算的更简单电路

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-24 DOI: 10.1038/s41534-025-00979-1

Yin Mo, Lei Zhang, Yu-Ao Chen, Yingjian Liu, Tengxiang Lin, Xin Wang

{"title":"Parameterized quantum comb and simpler circuits for reversing unknown qubit-unitary operations","authors":"Yin Mo, Lei Zhang, Yu-Ao Chen, Yingjian Liu, Tengxiang Lin, Xin Wang","doi":"10.1038/s41534-025-00979-1","DOIUrl":"https://doi.org/10.1038/s41534-025-00979-1","url":null,"abstract":"Quantum combs play a vital role in characterizing and transforming quantum processes, with wide-ranging applications in quantum information processing. However, obtaining the explicit quantum circuit for the desired quantum comb remains a challenging problem. We propose PQComb, a novel framework that employs parameterized quantum circuits (PQCs) or quantum neural networks to harness the full potential of quantum combs for diverse quantum process transformation tasks. This method is well-suited for near-term quantum devices and can be applied to various tasks in quantum machine learning. As a notable application, we present two streamlined protocols for the time-reversal simulation of unknown qubit unitary evolutions, reducing the ancilla qubit overhead from six to three compared to the previous best-known method. We also extend PQComb to solve the problems of qutrit unitary transformation and channel discrimination. Furthermore, we demonstrate the hardware efficiency and robustness of our qubit unitary inversion protocol under realistic noise simulations of IBM-Q superconducting quantum hardware, yielding a significant improvement in average similarity over the previous protocol under practical regimes. PQComb’s versatility and potential for broader applications in quantum machine learning pave the way for more efficient and practical solutions to complex quantum tasks.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"27 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143477572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Check-probe spectroscopy of lifetime-limited emitters in bulk-grown silicon carbide 体生长碳化硅中寿命限制发射体的检查探针光谱

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-22 DOI: 10.1038/s41534-025-00985-3

G. L. van de Stolpe, L. J. Feije, S. J. H. Loenen, A. Das, G. M. Timmer, T. W. de Jong, T. H. Taminiau

{"title":"Check-probe spectroscopy of lifetime-limited emitters in bulk-grown silicon carbide","authors":"G. L. van de Stolpe, L. J. Feije, S. J. H. Loenen, A. Das, G. M. Timmer, T. W. de Jong, T. H. Taminiau","doi":"10.1038/s41534-025-00985-3","DOIUrl":"https://doi.org/10.1038/s41534-025-00985-3","url":null,"abstract":"Solid-state single-photon emitters provide a versatile platform for exploring quantum technologies such as optically connected quantum networks. A key challenge is to ensure the optical coherence and spectral stability of the emitters. Here, we introduce a high-bandwidth ‘check-probe’ scheme to quantitatively measure (laser-induced) spectral diffusion and ionisation rates, as well as homogeneous linewidths. We demonstrate these methods on single V2 centres in commercially available bulk-grown 4H-silicon carbide. Despite observing significant spectral diffusion under laser illumination (≳GHz s−1), the optical transitions are narrow (~35 MHz), and remain stable in the dark (≳1 s). Through Landau-Zener-Stückelberg interferometry, we determine the optical coherence to be near-lifetime limited (T2 = 16.4(4) ns), hinting at the potential for using bulk-grown materials for developing quantum technologies. These results advance our understanding of spectral diffusion of quantum emitters in semiconductor materials, and may have applications for studying charge dynamics across other platforms.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"23 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143473551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Direct entanglement detection of quantum systems using machine learning 使用机器学习的量子系统直接纠缠检测

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-20 DOI: 10.1038/s41534-025-00970-w

Yulei Huang, Liangyu Che, Chao Wei, Feng Xu, Xinfang Nie, Jun Li, Dawei Lu, Tao Xin

引用次数: 0