npj Quantum Information最新文献_第6页

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

Remote cooling of spin-ensembles through a spin-mechanical hybrid interface 通过自旋-机械混合界面远程冷却自旋系综

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-07 DOI: 10.1038/s41534-025-00968-4

Yang Wang, Durga Bhaktavatsala Rao Dasari, Jörg Wrachtrup

引用次数: 0

Universal validity of the second law of information thermodynamics 信息热力学第二定律的普遍有效性

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-07 DOI: 10.1038/s41534-024-00922-w

Shintaro Minagawa, M. Hamed Mohammady, Kenta Sakai, Kohtaro Kato, Francesco Buscemi

{"title":"Universal validity of the second law of information thermodynamics","authors":"Shintaro Minagawa, M. Hamed Mohammady, Kenta Sakai, Kohtaro Kato, Francesco Buscemi","doi":"10.1038/s41534-024-00922-w","DOIUrl":"https://doi.org/10.1038/s41534-024-00922-w","url":null,"abstract":"Adiabatic measurements, followed by feedback and erasure protocols, have often been considered as a model to embody Maxwell’s Demon paradox and to study the interplay between thermodynamics and information processing. Such studies have led to the conclusion, now widely accepted in the community, that Maxwell’s Demon and the second law of thermodynamics can peacefully coexist because any gain provided by the demon must be offset by the cost of performing the measurement and resetting the demon’s memory to its initial state. Statements of this kind are collectively referred to as second laws of information thermodynamics and have recently been extended to include quantum theoretical scenarios. However, previous studies in this direction have made several assumptions, particularly about the feedback process and the demon’s memory readout, and thus arrived at statements that are not universally applicable and whose range of validity is not clear. In this work, we fill this gap by precisely characterizing the full range of quantum feedback control and erasure protocols that are overall consistent with the second law of thermodynamics. This leads us to conclude that the second law of information thermodynamics is indeed universal: it must hold for any quantum feedback control and erasure protocol, regardless of the measurement process involved, as long as the protocol is overall compatible with thermodynamics. Our comprehensive analysis not only encompasses new scenarios but also retrieves previous ones, doing so with fewer assumptions. This simplification contributes to a clearer understanding of the theory.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"12 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143258676","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

Microscopic parametrizations for gate set tomography under coloured noise 彩色噪声下门集层析成像的微观参数化

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-06 DOI: 10.1038/s41534-025-00976-4

P. Viñas, A. Bermudez

引用次数: 0

Low-error encoder for time-bin and decoy states for quantum key distribution 用于时间箱和量子密钥分发的诱饵状态的低误差编码器

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-06 DOI: 10.1038/s41534-024-00923-9

Davide Scalcon, Elisa Bazzani, Giuseppe Vallone, Paolo Villoresi, Marco Avesani

引用次数: 0

Scalable temporal multiplexing of telecom photons via thin-film lithium niobate photonics 利用薄膜铌酸锂光子学实现电信光子的可伸缩时间复用

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-06 DOI: 10.1038/s41534-024-00929-3

Çağın Ekici, Yonghe Yu, Jeremy C. Adcock, Alif Laila Muthali, Mujtaba Zahidy, Heyun Tan, Zhongjin Lin, Hao Li, Leif K. Oxenløwe, Xinlun Cai, Yunhong Ding

{"title":"Scalable temporal multiplexing of telecom photons via thin-film lithium niobate photonics","authors":"Çağın Ekici, Yonghe Yu, Jeremy C. Adcock, Alif Laila Muthali, Mujtaba Zahidy, Heyun Tan, Zhongjin Lin, Hao Li, Leif K. Oxenløwe, Xinlun Cai, Yunhong Ding","doi":"10.1038/s41534-024-00929-3","DOIUrl":"https://doi.org/10.1038/s41534-024-00929-3","url":null,"abstract":"Efficient single-photon generation remains a big challenge in quantum photonics. A promising approach to overcome this challenge is to employ active multiplexing—repeating a nondeterministic photon pair generation process across orthogonal degrees of freedom and exploiting heralding to actively route the heralded photon to the desired single output mode via feedforward. The main barriers of multiplexing schemes, however, are minimizing resource requirements to allow scalability and the lack of availability of high-speed, low-loss switches. Here, we present an on-chip temporal multiplexing scheme utilizing thin-film lithium niobate (TFLN) photonics to effectively address these challenges. Our time-multiplexed source, operating at a rate of 62.2 MHz, enhances single-photon probability by a factor of 3.37 ± 0.05 without introducing additional multi-photon noise. This demonstration highlights the feasibility and potential of TFLN photonics for large-scale complex quantum information technologies.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"31 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143191972","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

State estimation with quantum extreme learning machines beyond the scrambling time 超越置乱时间的量子极限学习机状态估计

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-03 DOI: 10.1038/s41534-024-00927-5

Marco Vetrano, Gabriele Lo Monaco, Luca Innocenti, Salvatore Lorenzo, G. Massimo Palma

引用次数: 0

Programmable quantum circuits in a large-scale photonic waveguide array 大规模光子波导阵列中的可编程量子电路

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-02-03 DOI: 10.1038/s41534-024-00934-6

Yang Yang, Robert J. Chapman, Akram Youssry, Ben Haylock, Francesco Lenzini, Mirko Lobino, Alberto Peruzzo

引用次数: 0

Tantalum airbridges for scalable superconducting quantum processors 用于可扩展超导量子处理器的钽气桥

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-01-29 DOI: 10.1038/s41534-025-00972-8

Kunliang Bu, Sainan Huai, Zhenxing Zhang, Dengfeng Li, Yuan Li, Jingjing Hu, Xiaopei Yang, Maochun Dai, Tianqi Cai, Yi-Cong Zheng, Shengyu Zhang

{"title":"Tantalum airbridges for scalable superconducting quantum processors","authors":"Kunliang Bu, Sainan Huai, Zhenxing Zhang, Dengfeng Li, Yuan Li, Jingjing Hu, Xiaopei Yang, Maochun Dai, Tianqi Cai, Yi-Cong Zheng, Shengyu Zhang","doi":"10.1038/s41534-025-00972-8","DOIUrl":"https://doi.org/10.1038/s41534-025-00972-8","url":null,"abstract":"The unique property of tantalum, particularly its exceptional resistance to both acid and alkali, makes it promising for superconducting quantum processors. Here, we propose a novel lift-off method for fabricating tantalum airbridges with separate or fully-capped structures. This method introduces an aluminum film as a barrier layer to separate two layers of photoresist, which is then etched away before depositing tantalum film. We experimentally characterize these tantalum airbridges as control line jumpers, ground plane crossovers and coupling elements, and further validate the overall adaptability by a 13-qubit quantum processor with a median T1 exceeding 100 μs. The median single-qubit gate fidelity is measured at 99.95(2)% for isolated Randomized Benchmarking and 99.94(2)% for the simultaneous one. Additionally, the experimental achievement of airbridge coupling with a controlled-Z gate fidelity surpassing 99.2(2)% in a separate two-qubit quantum chip may facilitate scalable quantum computation and quantum error correction with entirely tantalum elements.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"1245 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143054862","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

Gate modulation of the hole singlet-triplet qubit frequency in germanium 锗中空穴单重态-三重态量子比特频率的门调制

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-01-29 DOI: 10.1038/s41534-024-00953-3

John Rooney, Zhentao Luo, Lucas E. A. Stehouwer, Giordano Scappucci, Menno Veldhorst, Hong-Wen Jiang

{"title":"Gate modulation of the hole singlet-triplet qubit frequency in germanium","authors":"John Rooney, Zhentao Luo, Lucas E. A. Stehouwer, Giordano Scappucci, Menno Veldhorst, Hong-Wen Jiang","doi":"10.1038/s41534-024-00953-3","DOIUrl":"https://doi.org/10.1038/s41534-024-00953-3","url":null,"abstract":"Spin qubits in germanium gate-defined quantum dots have made considerable progress within the last few years, partially due to their strong spin-orbit coupling and site-dependent g-tensors. While this characteristic of the g-factors removes the need for micromagnets and allows for the possibility of all-electric qubit control, relying on these g-tensors necessitates the need to understand their sensitivity to the confinement potential that defines the quantum dots. Here, we demonstrate a S − T_ qubit whose frequency is a strong function of the voltage applied to the barrier gate shared by the quantum dots. We find a g-factor that can be approximately increased by an order of magnitude adjusting the barrier gate voltage only by 12 mV. We show how this strong dependence could potentially be attributed to the dots moving through a variable strain environment in our device. This work not only reinforces previous findings that site-dependent g-tensors in germanium can be utilized for qubit manipulation, but reveals the sensitivity and tunability these g-tensors have to the electrostatic confinement of the quantum dot.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"37 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143054863","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