npj Quantum Information最新文献_第4页

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

Parallel circuit implementation of variational quantum algorithms 变分量子算法的并行电路实现

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-19 DOI: 10.1038/s41534-025-00982-6

Michele Cattelan, Sheir Yarkoni, Wolfgang Lechner

引用次数: 0

Maximal steady-state entanglement in autonomous quantum thermal machines 自主量子热机中的最大稳态纠缠

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-19 DOI: 10.1038/s41534-025-00981-7

Shishir Khandelwal, Björn Annby-Andersson, Giovanni Francesco Diotallevi, Andreas Wacker, Armin Tavakoli

引用次数: 0

Stabilization of Kerr-cat qubits with quantum circuit refrigerator 用量子电路制冷机稳定Kerr-cat量子比特

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-15 DOI: 10.1038/s41534-025-00974-6

Shumpei Masuda, Shunsuke Kamimura, Tsuyoshi Yamamoto, Takaaki Aoki, Akiyoshi Tomonaga

引用次数: 0

Contextual subspace variational quantum eigensolver calculation of the dissociation curve of molecular nitrogen on a superconducting quantum computer 超导量子计算机上分子氮解离曲线的上下文子空间变分量子特征解算

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-12 DOI: 10.1038/s41534-024-00952-4

Tim Weaving, Alexis Ralli, Peter J. Love, Sauro Succi, Peter V. Coveney

{"title":"Contextual subspace variational quantum eigensolver calculation of the dissociation curve of molecular nitrogen on a superconducting quantum computer","authors":"Tim Weaving, Alexis Ralli, Peter J. Love, Sauro Succi, Peter V. Coveney","doi":"10.1038/s41534-024-00952-4","DOIUrl":"https://doi.org/10.1038/s41534-024-00952-4","url":null,"abstract":"We present an experimental demonstration of the Contextual Subspace Variational Quantum Eigensolver on superconducting hardware. Calculating the potential energy curve of molecular nitrogen proves challenging for many conventional quantum chemistry techniques, since static correlation dominates in the dissociation limit. Our quantum simulations retain good agreement with the Full Configuration Interaction energy, outperforming all benchmarked single-reference wavefunction techniques in capturing the bond-breaking appropriately. Moreover, our methodology is competitive with multiconfigurational approaches but at a saving of quantum resource, meaning larger active spaces can be treated for a fixed qubit allowance. To achieve this result, we deploy an error mitigation/suppression strategy comprised of Dynamical Decoupling, Measurement-Error Mitigation and Zero-Noise Extrapolation. Circuit parallelization also provides passive noise-averaging and improves the effective shot yield to reduce the measurement overhead. Furthermore, we introduce a modified adaptive ansatz construction algorithm that incorporates hardware awareness into our variational circuits, minimizing the transpilation cost for the target qubit topology.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"78 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393008","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