Quantum Science and Technology最新文献_第8页

Bounding fidelity in quantum feedback control: theory and applications to Dicke state preparation 量子反馈控制中的边界保真度：理论及其在Dicke态制备中的应用

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-06-26 DOI: 10.1088/2058-9565/ade55f

Eoin O’Connor, Hailan Ma and Marco G Genoni

引用次数: 0

Percolation thresholds and connectivity in quantum networks 量子网络中的渗透阈值和连通性

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-06-25 DOI: 10.1088/2058-9565/ade55e

Andrea De Girolamo, Giuseppe Magnifico and Cosmo Lupo

{"title":"Percolation thresholds and connectivity in quantum networks","authors":"Andrea De Girolamo, Giuseppe Magnifico and Cosmo Lupo","doi":"10.1088/2058-9565/ade55e","DOIUrl":"https://doi.org/10.1088/2058-9565/ade55e","url":null,"abstract":"We study entanglement percolation in qubit-based planar quantum network models of arbitrary topology, where neighboring nodes are initially connected by pure states with quenched disorder in their entanglement. To address this, we develop a physics-informed heuristic algorithm designed to find a sequence of entanglement swapping and distillation operations to connect any pair of distant nodes. The algorithm combines locally optimal percolation strategies between nodes at a maximum distance of one swapping operation. If this fails to produce a maximally entangled state, it looks for alternative paths surrounding intermediate states within the process. We analytically find and numerically verify thresholds in quantum percolation, which depend on the initial network configuration and entanglement, and are associated with specific percolation strategies. We classify these strategies based on the connectivity, a quantity that relates the entanglement in the final state and the level of integrity of the network at the end of the process. We find distinct regimes of quantum percolation, which are clearly separated by the percolation thresholds of the employed strategies and vastly vary according to the network topology.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"58 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Coherence of quantum non-Gaussian states via nonlinear absorption of quanta 量子非高斯态的非线性吸收相干性

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-06-25 DOI: 10.1088/2058-9565/ade334

Kingshuk Adhikary, Darren W Moore and Radim Filip

{"title":"Coherence of quantum non-Gaussian states via nonlinear absorption of quanta","authors":"Kingshuk Adhikary, Darren W Moore and Radim Filip","doi":"10.1088/2058-9565/ade334","DOIUrl":"https://doi.org/10.1088/2058-9565/ade334","url":null,"abstract":"The linear and phase insensitive absorption of a single quanta via coherent interactions with a saturable system, even a single ground state qubit, is sufficient to deterministically generate quantum non-Gaussian states in an oscillator, even stimulated merely by increasing thermal oscillator energy. However, the resultant states only approach Fock states and therefore do not exhibit quantum coherence. Here we overcome this limitation using a minimal step: a nonlinear phase-insensitive absorption process added to the linear one. The coherent addition of such individually passive processes allows coherence to emerge and increase in phase space without an external drive and with minimal interaction requirements. The coherence of quantum non-Gaussian states emerges because the linear and nonlinear absorption processes are not mutually passive. In the simplest case rotationally symmetric Wigner functions of the oscillator Fock states convert their many negative regions to an extremely complex asymmetric structure in sharp contrast to the rotational symmetry of those obtained by the individual interactions. We extend this case to include an unsaturable absorber (oscillator) and analyse switching between linear and nonlinear absorptions, suitable for broad classes of experiments.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"46 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Multi-mode global driving of trapped ions for quantum circuit synthesis 量子电路合成中捕获离子的多模全局驱动

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-06-25 DOI: 10.1088/2058-9565/ade560

Philip Richerme

引用次数: 0

Dynamical structure factor from weak measurements 弱测量的动力结构因子

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-06-24 DOI: 10.1088/2058-9565/ade335

E Altuntaş, R G Lena, S Flannigan, A J Daley and I B Spielman

{"title":"Dynamical structure factor from weak measurements","authors":"E Altuntaş, R G Lena, S Flannigan, A J Daley and I B Spielman","doi":"10.1088/2058-9565/ade335","DOIUrl":"https://doi.org/10.1088/2058-9565/ade335","url":null,"abstract":"Much of our knowledge of quantum systems is encapsulated in the expectation value of Hermitian operators, experimentally obtained by averaging projective measurements. However, dynamical properties are often described by products of operators evaluated at different times; such observables cannot be measured by individual projective measurements, which occur at a single time. For example, the dynamical structure factor (DSF) describes the propagation of density excitations, such as phonons, and is derived from the spatial density operator evaluated at different times. In equilibrium systems this can be obtained by first exciting the system at a specific wavevector and frequency, then measuring the response. Here, we describe an alternative approach using a pair of time-separated weak measurements, and analytically show that their cross-correlation function directly recovers the DSF, for all systems, even far from equilibrium. This general schema can be applied to obtain the cross-correlation function of any pair of weakly observable quantities. We provide numerical confirmation of this technique with a matrix product states simulation of the one-dimensional Bose–Hubbard model, weakly measured by phase contrast imaging. We explore the limits of the method and demonstrate its applicability to real experiments with limited imaging resolution.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"13 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144479076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Communication with quantum catalysts 与量子催化剂的通信

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-06-24 DOI: 10.1088/2058-9565/ade284

Yuqi Li, Junjing Xing, Dengke Qu, Lei Xiao, Zhaobing Fan, Zhu-Jun Zheng, Haitao Ma, Peng Xue, Kishor Bharti, Dax Enshan Koh and Yunlong Xiao

{"title":"Communication with quantum catalysts","authors":"Yuqi Li, Junjing Xing, Dengke Qu, Lei Xiao, Zhaobing Fan, Zhu-Jun Zheng, Haitao Ma, Peng Xue, Kishor Bharti, Dax Enshan Koh and Yunlong Xiao","doi":"10.1088/2058-9565/ade284","DOIUrl":"https://doi.org/10.1088/2058-9565/ade284","url":null,"abstract":"Communication is essential for advancing science and technology. Quantum communication, in particular, benefits from the use of catalysts. During the communication process, these catalysts enhance performance while remaining unchanged. Although chemical catalysts that undergo deactivation typically perform worse than those that remain unaffected, quantum catalysts, referred to as embezzling catalysts, can surprisingly outperform their non-deactivating counterparts despite experiencing slight alterations. In this work, we employ embezzling quantum catalysts to enhance the transmission of both quantum and classical information. By utilizing finite-dimensional embezzling catalysts, we guarantee a non-zero catalytic channel capacity for any quantum channel while keeping variations in the catalytic system arbitrarily small. Our protocol also improves long-distance entanglement distribution. Furthermore, we introduce catalytic superdense coding, demonstrating how embezzling catalysts can boost the transmission of classical information. Finally, we explore methods to reduce the dimensionality of catalysts, a step toward making quantum catalysis a practical reality.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"53 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144479066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Thirty years of quantum computing 三十年的量子计算

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-06-22 DOI: 10.1088/2058-9565/ade0e4

David P DiVincenzo

引用次数: 0

Classical shadows with improved median-of-means estimation 改进中位数估计的经典阴影

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-06-19 DOI: 10.1088/2058-9565/addffd

Winston Fu, Dax Enshan Koh, Siong Thye Goh and Jian Feng Kong

{"title":"Classical shadows with improved median-of-means estimation","authors":"Winston Fu, Dax Enshan Koh, Siong Thye Goh and Jian Feng Kong","doi":"10.1088/2058-9565/addffd","DOIUrl":"https://doi.org/10.1088/2058-9565/addffd","url":null,"abstract":"The classical shadows protocol, introduced by Huang et al (2020 Nat. Phys.16 1050), makes use of the median-of-means (MoM) estimator to efficiently estimate the expectation values of M observables with failure probability δ using only measurements. In their analysis, Huang et al used loose constants in their asymptotic performance bounds for simplicity. However, the specific values of these constants can significantly affect the number of shots used in practical implementations. To address this, we studied a modified MoM estimator proposed by Minsker (2023 Proc. 36th Conf. on Learning Theory (PMLR) 195 5925) that uses optimal constants and involves a U-statistic over the data set. For efficient estimation, we implemented two types of incomplete U-statistics estimators, the first based on random sampling and the second based on cyclically permuted sampling. We compared the performance of the original and modified estimators when used with the classical shadows protocol with single-qubit Clifford unitaries (Pauli measurements) for an Ising spin chain, and global Clifford unitaries (Clifford measurements) for the Greenberger–Horne–Zeilinger state. While the original estimator outperformed the modified estimators for Pauli measurements, the modified estimators showed improved performance over the original estimator for Clifford measurements. Our findings highlight the importance of tailoring estimators to specific measurement settings to optimize the performance of the classical shadows protocol in practical applications.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"44 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Experimental demonstration of enhanced quantum tomography via quantum reservoir processing 利用量子库处理增强量子层析成像的实验演示

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-06-19 DOI: 10.1088/2058-9565/addffe

Tanjung Krisnanda, Pengtao Song, Adrian Copetudo, Clara Yun Fontaine, Tomasz Paterek, Timothy C H Liew and Yvonne Y Gao

{"title":"Experimental demonstration of enhanced quantum tomography via quantum reservoir processing","authors":"Tanjung Krisnanda, Pengtao Song, Adrian Copetudo, Clara Yun Fontaine, Tomasz Paterek, Timothy C H Liew and Yvonne Y Gao","doi":"10.1088/2058-9565/addffe","DOIUrl":"https://doi.org/10.1088/2058-9565/addffe","url":null,"abstract":"Quantum machine learning is a rapidly advancing discipline that leverages the features of quantum mechanics to enhance the performance of computational tasks. Quantum reservoir processing (QRP), which allows efficient optimization of a single output layer without precise control over the quantum system, stands out as one of the most versatile and practical quantum machine learning techniques. Here we experimentally demonstrate a QRP approach for continuous-variable state reconstruction on a bosonic circuit quantum electrodynamics platform. The scheme learns the true dynamical process through a minimum set of measurement outcomes of a known set of initial states. We show that the map learnt this way achieves high reconstruction fidelity for several test states, offering significantly enhanced performance over using a map calculated based on an idealized model of the system. This is due to a key feature of reservoir processing which accurately accounts for physical non-idealities such as decoherence, spurious dynamics, and systematic errors. Our results present a valuable tool for robust bosonic state and process reconstruction, concretely demonstrating the power of QRP in enhancing real-world applications.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"607 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Single photon coherent Ising machines for constrained optimization problems 约束优化问题的单光子相干伊辛机

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-06-19 DOI: 10.1088/2058-9565/addde5

Masahito Kumagai, Yoshitaka Inui, Edwin Ng, Satoshi Kako, Kazuhiko Komatsu, Hiroaki Kobayashi and Yoshihisa Yamamoto

{"title":"Single photon coherent Ising machines for constrained optimization problems","authors":"Masahito Kumagai, Yoshitaka Inui, Edwin Ng, Satoshi Kako, Kazuhiko Komatsu, Hiroaki Kobayashi and Yoshihisa Yamamoto","doi":"10.1088/2058-9565/addde5","DOIUrl":"https://doi.org/10.1088/2058-9565/addde5","url":null,"abstract":"A Coherent Ising machine (CIM) is an oscillator-network-based analog computing system to circumvent the bottleneck in von Neumann digital computing architectures. The CIM consists of a network of degenerate optical parametric oscillators (DOPOs) and is designed to find a ground state or perform Boltzmann sampling for all degenerate ground states and low-energy excited states in combinatorial optimization problems. A nonlinear measurement feedback scheme, called chaotic amplitude control (CAC), has recently been proposed to correct pulse amplitude inhomogeneity and thereby faithfully map the Ising Hamiltonian to the loss landscape of the DOPO network. However, the quantum limit of the CIM-CAC performance is not fully explored yet. This work clarifies how the quantum noise squeezing and the measurement-induced state shift in repeated indirect quantum measurements improve the system performance. From the numerical simulation on the Ising model with the Zeeman terms, obtained from combinatorial clustering problems formulated as constrained optimization problems, it is revealed that the CIM-CAC operating in a single photon per pulse regime dramatically outperforms the standard CIM-CAC with a large photon number per pulse. This is because the standard CIM-CAC is often trapped in a periodic trajectory and cannot escape from there. On the other hand, the significant improvement is brought by the noise-induced amplitude jump in the single photon CIM-CAC.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"15 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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