npj Quantum Information最新文献_第10页

Simultaneous measurement of multiple incompatible observables and tradeoff in multiparameter quantum estimation 多参数量子估算中多个不兼容观测变量的同时测量与权衡

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-10-06 DOI: 10.1038/s41534-024-00894-x

Hongzhen Chen, Lingna Wang, Haidong Yuan

{"title":"Simultaneous measurement of multiple incompatible observables and tradeoff in multiparameter quantum estimation","authors":"Hongzhen Chen, Lingna Wang, Haidong Yuan","doi":"10.1038/s41534-024-00894-x","DOIUrl":"https://doi.org/10.1038/s41534-024-00894-x","url":null,"abstract":"How well can multiple incompatible observables be implemented by a single measurement? This is a fundamental problem in quantum mechanics with wide implications for the performance optimization of numerous tasks in quantum information science. While existing studies have been mostly focusing on the approximation of two observables with a single measurement, in practice multiple observables are often encountered, for which the errors of the approximations are little understood. Here we provide a framework to study the implementation of an arbitrary finite number of observables with a single measurement. Our methodology yields novel analytical bounds on the errors of these implementations, significantly advancing our understanding of this fundamental problem. Additionally, we introduce a more stringent bound utilizing semi-definite programming that, in the context of two observables, generates an analytical bound tighter than previously known bounds. The derived bounds have direct applications in assessing the trade-off between the precision of estimating multiple parameters in quantum metrology, an area with crucial theoretical and practical implications. To validate the validity of our findings, we conducted experimental verification using a superconducting quantum processor. This experimental validation not only confirms the theoretical results but also effectively bridges the gap between the derived bounds and empirical data obtained from real-world experiments. Our work paves the way for optimizing various tasks in quantum information science that involve multiple noncommutative observables.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"46 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142379281","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

Gibbs state sampling via cluster expansions 通过集群扩展进行吉布斯状态采样

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-10-04 DOI: 10.1038/s41534-024-00887-w

Norhan M. Eassa, Mahmoud M. Moustafa, Arnab Banerjee, Jeffrey Cohn

{"title":"Gibbs state sampling via cluster expansions","authors":"Norhan M. Eassa, Mahmoud M. Moustafa, Arnab Banerjee, Jeffrey Cohn","doi":"10.1038/s41534-024-00887-w","DOIUrl":"https://doi.org/10.1038/s41534-024-00887-w","url":null,"abstract":"Gibbs states (i.e., thermal states) can be used for several applications such as quantum simulation, quantum machine learning, quantum optimization, and the study of open quantum systems. Moreover, semi-definite programming, combinatorial optimization problems, and training quantum Boltzmann machines can all be addressed by sampling from well-prepared Gibbs states. With that, however, comes the fact that preparing and sampling from Gibbs states on a quantum computer are notoriously difficult tasks. Such tasks can require large overhead in resources and/or calibration even in the simplest of cases, as well as the fact that the implementation might be limited to only a specific set of systems. We propose a method based on sampling from a quasi-distribution consisting of tensor products of mixed states on local clusters, i.e., expanding the full Gibbs state into a sum of products of local “Gibbs-cumulant” type states easier to implement and sample from on quantum hardware. We begin with presenting results for 4-spin linear chains with XY spin interactions, for which we obtain the ZZ dynamical spin-spin correlation functions and dynamical structure factor. We also present the results of measuring the specific heat of the 8-spin chain Gibbs state ρ8.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"5 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142377269","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

High-fidelity spin readout via the double latching mechanism 通过双锁扣机制实现高保真自旋读数

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-10-03 DOI: 10.1038/s41534-024-00882-1

Haruki Kiyama, Danny van Hien, Arne Ludwig, Andreas D. Wieck, Akira Oiwa

引用次数: 0

Gate-set evaluation metrics for closed-loop optimal control on nitrogen-vacancy center ensembles in diamond 金刚石氮空位中心集合闭环优化控制的门集评估指标

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-10-02 DOI: 10.1038/s41534-024-00893-y

Philipp J. Vetter, Thomas Reisser, Maximilian G. Hirsch, Tommaso Calarco, Felix Motzoi, Fedor Jelezko, Matthias M. Müller

{"title":"Gate-set evaluation metrics for closed-loop optimal control on nitrogen-vacancy center ensembles in diamond","authors":"Philipp J. Vetter, Thomas Reisser, Maximilian G. Hirsch, Tommaso Calarco, Felix Motzoi, Fedor Jelezko, Matthias M. Müller","doi":"10.1038/s41534-024-00893-y","DOIUrl":"https://doi.org/10.1038/s41534-024-00893-y","url":null,"abstract":"A recurring challenge in quantum science and technology is the precise control of their underlying dynamics that lead to the desired quantum operations, often described by a set of quantum gates. These gates can be subject to application-specific errors, leading to a dependence of their controls on the chosen circuit, the quality measure and the gate-set itself. A natural solution would be to apply quantum optimal control in an application-oriented fashion. In turn, this requires the definition of a meaningful measure of the contextual gate-set performance. Therefore, we explore and compare the applicability of quantum process tomography, linear inversion gate-set tomography, randomized linear gate-set tomography, and randomized benchmarking as measures for closed-loop quantum optimal control experiments, using a macroscopic ensemble of nitrogen-vacancy centers in diamond as a test-bed. Our work demonstrates the relative trade-offs between those measures and how to significantly enhance the gate-set performance, leading to an improvement across all investigated methods.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"25 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142363012","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

Secure and robust randomness with sequential quantum measurements 利用顺序量子测量实现安全稳健的随机性

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-09-30 DOI: 10.1038/s41534-024-00879-w

Matteo Padovan, Giulio Foletto, Lorenzo Coccia, Marco Avesani, Paolo Villoresi, Giuseppe Vallone

{"title":"Secure and robust randomness with sequential quantum measurements","authors":"Matteo Padovan, Giulio Foletto, Lorenzo Coccia, Marco Avesani, Paolo Villoresi, Giuseppe Vallone","doi":"10.1038/s41534-024-00879-w","DOIUrl":"https://doi.org/10.1038/s41534-024-00879-w","url":null,"abstract":"Quantum correlations between measurements of separated observers are crucial for applications like randomness generation and key distribution. Although device-independent security can be certified with minimal assumptions, current protocols have limited performance. Here, we exploit sequential measurements, defined with a precise temporal order, to enhance performance by reusing quantum states. We provide a geometric perspective and a general mathematical framework, analytically proving a Tsirelson-like boundary for sequential quantum correlations, which represents a trade-off in nonlocality shared by sequential users. This boundary is advantageous for secure quantum randomness generation, certifying maximum bits per state with one remote and two sequential parties, even if one sequential user shares no nonlocality. Our simple qubit protocol reaches this boundary, and numerical analysis shows improved robustness under realistic noise. A photonic implementation confirms feasibility and robustness. This study advances the understanding of sequential quantum correlations and offers insights for efficient device-independent protocols.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"23 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142330333","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

Randomized semi-quantum matrix processing 随机半量子矩阵处理

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-09-30 DOI: 10.1038/s41534-024-00883-0

Allan Tosta, Thais de Lima Silva, Giancarlo Camilo, Leandro Aolita

引用次数: 0

Protocol for certifying entanglement in surface spin systems using a scanning tunneling microscope 利用扫描隧道显微镜认证表面自旋系统纠缠的协议

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-09-28 DOI: 10.1038/s41534-024-00888-9

Rik Broekhoven, Curie Lee, Soo-hyon Phark, Sander Otte, Christoph Wolf

引用次数: 0

Superdiffusive to ballistic transport in nonintegrable Rydberg simulator 非积分雷德贝格模拟器中的超扩散到弹道输运

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-09-19 DOI: 10.1038/s41534-024-00884-z

Chun Chen, Yan Chen, Xiaoqun Wang

{"title":"Superdiffusive to ballistic transport in nonintegrable Rydberg simulator","authors":"Chun Chen, Yan Chen, Xiaoqun Wang","doi":"10.1038/s41534-024-00884-z","DOIUrl":"https://doi.org/10.1038/s41534-024-00884-z","url":null,"abstract":"A common wisdom posits that transport of conserved quantities across clean nonintegrable quantum systems at high temperatures is diffusive when probed from the emergent hydrodynamic regime. We show that this empirical paradigm may alter if the strong interaction limit is taken. Using Krylov-typicality and purification matrix-product-state methods, we establish in short-to-intermediate time scales the following observations for the nonintegrable lattice model imitating the experimental Rydberg blockade simulator. Given the strict projection owing to the infinite density-density repulsion V, the Rydberg chain’s energy transport in the presence of a transverse field g is tentatively superdiffusive at infinite temperature featured by an anomalous scaling exponent (frac{3}{4}), indicating the potential existence of a novel dynamical universality class. Imposing, in addition, a growing longitudinal field h causes a putative superdiffusion-to-ballistic transport transition at h ≈ g. Interestingly, all the above results persist for large but finite interactions and temperatures, provided that the strongly interacting condition g, h ≪ kBT ≪ V is fulfilled. Our predictions are testable by current Rydberg quantum simulation facilities.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"14 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142245185","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

Demonstration of quantum network protocols over a 14-km urban fiber link 通过 14 千米城市光纤链路演示量子网络协议

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-09-14 DOI: 10.1038/s41534-024-00886-x

Stephan Kucera, Christian Haen, Elena Arenskötter, Tobias Bauer, Jonas Meiers, Marlon Schäfer, Ross Boland, Milad Yahyapour, Maurice Lessing, Ronald Holzwarth, Christoph Becher, Jürgen Eschner

引用次数: 0

Experimental preparation of multiphoton-added coherent states of light 光的多光子相干态的实验制备

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-09-14 DOI: 10.1038/s41534-024-00885-y

Jiří Fadrný, Michal Neset, Martin Bielak, Miroslav Ježek, Jan Bílek, Jaromír Fiurášek

{"title":"Experimental preparation of multiphoton-added coherent states of light","authors":"Jiří Fadrný, Michal Neset, Martin Bielak, Miroslav Ježek, Jan Bílek, Jaromír Fiurášek","doi":"10.1038/s41534-024-00885-y","DOIUrl":"https://doi.org/10.1038/s41534-024-00885-y","url":null,"abstract":"Conditional addition of photons represents a crucial tool for optical quantum state engineering and it forms a fundamental building block of advanced quantum photonic devices. Here we report on experimental implementation of the conditional addition of several photons. We demonstrate the addition of one, two, and three photons to input coherent states with various amplitudes. The resulting highly nonclassical photon-added states are completely characterized with time-domain homodyne tomography, and the nonclassicality of the prepared states is witnessed by the negativity of their Wigner functions. We experimentally demonstrate that the conditional addition of photons realizes approximate noiseless quantum amplification of coherent states with sufficiently large amplitude. We also investigate certification of the stellar rank of the generated multiphoton-added coherent states, which quantifies the non-Gaussian resources required for their preparation. Our results pave the way towards the experimental realization of complex optical quantum operations based on combination of multiple photon additions and subtractions.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"4 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142231454","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