npj Quantum Information最新文献_第3页

Energy-time and time-bin entanglement: past, present and future 能量-时间和时间桶的纠缠：过去、现在和未来

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-07-31 DOI: 10.1038/s41534-025-01072-3

Guilherme B. Xavier, Jan-Åke Larsson, Paolo Villoresi, Giuseppe Vallone, Adán Cabello

{"title":"Energy-time and time-bin entanglement: past, present and future","authors":"Guilherme B. Xavier, Jan-Åke Larsson, Paolo Villoresi, Giuseppe Vallone, Adán Cabello","doi":"10.1038/s41534-025-01072-3","DOIUrl":"https://doi.org/10.1038/s41534-025-01072-3","url":null,"abstract":"Entanglement is a key resource in many quantum information tasks. From a fundamental perspective entanglement is at the forefront of major philosophical discussions advancing our understanding of nature. An experimental scheme was proposed in 1989 by Franson that exploited the unpredictability in the generation time of a photon pair in order to produce a then new form of quantum entanglement, known as energy-time entanglement. A later modification gave rise to the very popular time-bin entanglement, an important cornerstone in many real-world quantum communication applications. Both forms of entanglement have radically pushed forward our understanding of quantum mechanics throughout the 1990s and 2000s. A decade later modifications to the original proposals were proposed and demonstrated, which opens the path for the highly sought-after device-independence capability for entanglement certification, with a goal of ultra-secure quantum communication. In this review we cover the beginnings of energy-time and time-bin entanglement, many key experiments that expanded our understanding of what was achievable in quantum information experiments all the way down to modern demonstrations based on new technological advances. We will then point out to the future discussing the important place that energy-time and time-bin entanglement will have in upcoming quantum networks and novel protocols based on nonlocality.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"27 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144747173","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

Entanglement-induced provable and robust quantum learning advantages 纠缠诱导的可证明和鲁棒量子学习优势

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-07-29 DOI: 10.1038/s41534-025-01078-x

Haimeng Zhao, Dong-Ling Deng

引用次数: 0

Classical simulability of constant-depth linear-optical circuits with noise 带噪声的等深度线性光电路的经典可模拟性

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-07-29 DOI: 10.1038/s41534-025-01041-w

Changhun Oh

{"title":"Classical simulability of constant-depth linear-optical circuits with noise","authors":"Changhun Oh","doi":"10.1038/s41534-025-01041-w","DOIUrl":"https://doi.org/10.1038/s41534-025-01041-w","url":null,"abstract":"Noise is one of the main obstacles to realizing quantum devices that achieve a quantum computational advantage. A possible approach to minimize the noise effect is to employ shallow-depth quantum circuits since noise typically accumulates as circuit depth grows. In this work, we investigate the complexity of shallow-depth linear-optical circuits under the effects of photon loss and partial distinguishability. By establishing a correspondence between a linear-optical circuit and a bipartite graph, we show that the effects of photon loss and partial distinguishability are equivalent to removing the corresponding vertices. Using this correspondence and percolation theory, we prove that for constant-depth linear-optical circuits with single photons, there is a threshold of loss (noise) rate above which the linear-optical systems can be decomposed into smaller systems with high probability, which enables us to simulate the systems efficiently. Consequently, our result implies that even in shallow-depth circuits where noise is not accumulated enough, its effect may be sufficiently significant to make them efficiently simulable using classical algorithms due to its entanglement structure constituted by shallow-depth circuits.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"51 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144737767","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

Alleviating the quantum Big-M problem 缓解量子Big-M问题

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-07-26 DOI: 10.1038/s41534-025-01067-0

Edoardo Alessandroni, Sergi Ramos-Calderer, Ingo Roth, Emiliano Traversi, Leandro Aolita

引用次数: 0

Robust quantum control using reinforcement learning from demonstration 基于强化学习的鲁棒量子控制

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-07-25 DOI: 10.1038/s41534-025-01065-2

Shengyong Li, Yidian Fan, Xiang Li, Xinhui Ruan, Qianchuan Zhao, Zhihui Peng, Re-Bing Wu, Jing Zhang, Pengtao Song

{"title":"Robust quantum control using reinforcement learning from demonstration","authors":"Shengyong Li, Yidian Fan, Xiang Li, Xinhui Ruan, Qianchuan Zhao, Zhihui Peng, Re-Bing Wu, Jing Zhang, Pengtao Song","doi":"10.1038/s41534-025-01065-2","DOIUrl":"https://doi.org/10.1038/s41534-025-01065-2","url":null,"abstract":"Quantum control requires high-precision and robust control pulses to ensure optimal system performance. However, control sequences generated with a system model may suffer from model bias, leading to low fidelity. While model-free reinforcement learning (RL) methods have been developed to avoid such biases, training an RL agent from scratch can be time-consuming, often taking hours to gather enough samples for convergence. This challenge has hindered the broad application of RL techniques to larger and more complex quantum control issues, limiting their adaptability. In this work, we use Reinforcement Learning from Demonstration (RLfD) to leverage the control sequences generated with system models and further optimize them with RL to avoid model bias. By avoiding learning from scratch and starting with reasonable control pulse shapes, this approach can increase sample efficiency by reducing the number of samples, which can significantly reduce the training time. Thus, this method can effectively handle pulse shapes that are discretized into more than 1000 pieces without compromising final fidelity. We have simulated the preparation of several high-fidelity non-classical states using the RLfD method. We also find that the training process is more stable when using RLfD. In addition, this method is suitable for fast gate calibration using reinforcement learning.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"11 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144710627","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 frequency resampling 量子频率重采样

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-07-25 DOI: 10.1038/s41534-025-01076-z

Emanuele Tumbiolo, Simone Roncallo, Chiara Macchiavello, Lorenzo Maccone

引用次数: 0

Counterfactual communication not achieved yet – A Comment on Salih et al. (2022) 反事实沟通尚未实现——对Salih等人的评论（2022）

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-07-24 DOI: 10.1038/s41534-025-00975-5

Sandu Popescu

引用次数: 0

Parameterized quantum circuits as universal generative models for continuous multivariate distributions 参数化量子电路作为连续多元分布的通用生成模型

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-07-22 DOI: 10.1038/s41534-025-01064-3

Alice Barthe, Michele Grossi, Sofia Vallecorsa, Jordi Tura, Vedran Dunjko

{"title":"Parameterized quantum circuits as universal generative models for continuous multivariate distributions","authors":"Alice Barthe, Michele Grossi, Sofia Vallecorsa, Jordi Tura, Vedran Dunjko","doi":"10.1038/s41534-025-01064-3","DOIUrl":"https://doi.org/10.1038/s41534-025-01064-3","url":null,"abstract":"Parameterized quantum circuits are a key component of quantum machine learning models for regression, classification, and generative tasks. Quantum Circuit Born machines produce discrete distributions over bitstrings whose length is exactly the number of qubits. To allow for distributions on continuous variables, new models have been introduced where classical randomness is uploaded into quantum circuits and expectation values are returned with a dimensionality decoupled from qubit number. While these models have been explored experimentally, their expressivity remains underexplored. In this work, we formalize this family and establish its theoretical foundation. We prove the universality of several variational circuit architectures for generating continuous multivariate distributions and derive tight resource bounds to reach universality using tools related to the Holevo bound. Our results reveal a trade-off between the number of qubits and measurements. We further explore relaxed notions of universality and present a practical use case, outlining potential domains for quantum advantage.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"98 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144677385","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

Spin-optomechanical cavity interfaces by deep subwavelength phonon-photon confinement 深亚波长声子光子约束下的自旋光力学腔界面

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-07-14 DOI: 10.1038/s41534-025-00999-x

Hamza Raniwala, Pratyush Anand, Stefan Krastanov, Matt Eichenfield, Matthew Trusheim, Dirk R. Englund

{"title":"Spin-optomechanical cavity interfaces by deep subwavelength phonon-photon confinement","authors":"Hamza Raniwala, Pratyush Anand, Stefan Krastanov, Matt Eichenfield, Matthew Trusheim, Dirk R. Englund","doi":"10.1038/s41534-025-00999-x","DOIUrl":"https://doi.org/10.1038/s41534-025-00999-x","url":null,"abstract":"A central goal of quantum information science is transferring qubits between space, time, and modality. Spin-based systems in solids are promising quantum memories, but high-fidelity transfer of their quantum states to telecom optical fields remains challenging. Here, we introduce a phonon-mediated interface between spins in a diamond nanobeam optomechanical crystal and telecom optical fields by a simultaneous deep-subwavelength confinement of optical and acoustic fields with mode volumes ({V}_{{rm{mech}}}/{Lambda }_{{rm{p}}}^{3} sim 1{0}^{-5}) and Vopt/λ3 ~ 10−3, respectively. This confinement boosts the spin-mechanical coupling rate of Group-IV silicon vacancy (SiV−) centers by an order of magnitude to ~ 32 MHz while retaining high acousto-optical couplings. The optical cavity couples to the spin irrespective of the emitter’s native excited states, avoiding spectral diffusion. Using Quantum Monte Carlo simulations, we estimate heralded entanglement fidelities exceeding 0.96 between two such interfaces. We anticipate broad utility beyond diamond emitter-telecom systems to most solid-state quantum memories.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"93 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144622468","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

A complexity transition in displaced Gaussian Boson sampling 位移高斯玻色子采样中的复杂性跃迁

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-07-09 DOI: 10.1038/s41534-025-01062-5

Zhenghao Li, Naomi R. Solomons, Jacob F. F. Bulmer, Raj B. Patel, Ian A. Walmsley

引用次数: 0