npj Quantum Information最新文献

Free-space continuous-variable quantum key distribution under high background noise

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-27 DOI: 10.1038/s41534-025-01009-w

Xue-Tao Zheng, Qi-Fa Zhang, Jie Ling, Guang-Can Guo, Zheng-Fu Han

引用次数: 0

Networking quantum networks with minimum cost aggregation 用最低成本聚合技术实现量子网络联网

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-21 DOI: 10.1038/s41534-025-01000-5

Koji Azuma

引用次数: 0

High-dimensional entanglement witnessed by correlations in arbitrary bases

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-19 DOI: 10.1038/s41534-025-00990-6

Nicky Kai Hong Li, Marcus Huber, Nicolai Friis

{"title":"High-dimensional entanglement witnessed by correlations in arbitrary bases","authors":"Nicky Kai Hong Li, Marcus Huber, Nicolai Friis","doi":"10.1038/s41534-025-00990-6","DOIUrl":"https://doi.org/10.1038/s41534-025-00990-6","url":null,"abstract":"Certifying entanglement is an important step in the development of many quantum technologies, especially for higher-dimensional systems, where entanglement promises increased capabilities for quantum communication and computation. A key feature distinguishing entanglement from classical correlations is the occurrence of correlations for complementary measurement bases. In particular, mutually unbiased bases (MUBs) are a paradigmatic example that is well-understood and routinely employed for entanglement certification. However, implementing unbiased measurements exactly is challenging and not generically possible for all physical platforms. Here, we extend the entanglement-certification toolbox from correlations in MUBs to arbitrary bases. This practically significant simplification paves the way for efficient characterizations of high-dimensional entanglement in a wide range of physical systems. Furthermore, we introduce a simple three-MUBs construction for all dimensions without using the Wootters–Fields construction, potentially simplifying experimental requirements when measurements in more than two MUBs are needed, especially in high-dimensional settings.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"16 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653476","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

Realizing ultrahigh capacity quantum superdense coding on quantum photonic chip

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-18 DOI: 10.1038/s41534-025-01007-y

Yuan Li, Huihui Zhu, Wei Luo, Hong Cai, Muhammad Faeyz Karim, Xianshu Luo, Feng Gao, Xiang Wu, Xiaoqi Zhou, Qinghua Song, Leong Chuan Kwek, Ai Qun Liu

{"title":"Realizing ultrahigh capacity quantum superdense coding on quantum photonic chip","authors":"Yuan Li, Huihui Zhu, Wei Luo, Hong Cai, Muhammad Faeyz Karim, Xianshu Luo, Feng Gao, Xiang Wu, Xiaoqi Zhou, Qinghua Song, Leong Chuan Kwek, Ai Qun Liu","doi":"10.1038/s41534-025-01007-y","DOIUrl":"https://doi.org/10.1038/s41534-025-01007-y","url":null,"abstract":"Quantum superdense coding provides a compelling solution to enhance the channel capacity compared with classical coding, which plays a vital role in quantum networks. However, the realization of a degenerate high-dimensional entangled state with high fidelity has remained an elusive challenge, limiting improvement in channel capacity. Here, we have demonstrated a 16-mode quantum process photonic chip and experimentally validated a degenerate eight-dimensional quDit entangled state with a fidelity of ({{0.973}}pm {{0.002}}). Moreover, we propose an efficient Bell state measurement method to distinguish eleven orthogonal Bell states in eight-dimensional quantum superdense coding. Leveraging the high-quality features of our quantum photonic chip, we have achieved an unprecedented channel capacity of ({{3.021}}pm {{0.003}}) bits, highlighting the largest channel capacity to date. Furthermore, our method presents a remarkable quantum advantage over classical schemes, the latter of which can only transmit a maximum of 3 bits in the environment without any noise. Our findings not only open up a new avenue for integrated quantum information processing, but also contribute significantly to the advancement of multidimensional technologies, facilitating the establishment of practical, high-capacity quantum networks.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"10503 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143653477","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-enhanced dark matter detection with in-cavity control: mitigating the Rayleigh curse

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-17 DOI: 10.1038/s41534-025-01004-1

Haowei Shi, Anthony J. Brady, Wojciech Górecki, Lorenzo Maccone, Roberto Di Candia, Quntao Zhuang

{"title":"Quantum-enhanced dark matter detection with in-cavity control: mitigating the Rayleigh curse","authors":"Haowei Shi, Anthony J. Brady, Wojciech Górecki, Lorenzo Maccone, Roberto Di Candia, Quntao Zhuang","doi":"10.1038/s41534-025-01004-1","DOIUrl":"https://doi.org/10.1038/s41534-025-01004-1","url":null,"abstract":"The nature of dark matter is a fundamental puzzle in modern physics. A major approach of searching for dark matter relies on detecting feeble noise in microwave cavities. However, the quantum advantages of common quantum resources such as squeezing are intrinsically limited by the Rayleigh curse—a constant loss places a sensitivity upper bound on these quantum resources. In this paper, we propose an in situ transient control to mitigate such Rayleigh limit. The protocol consists of three steps: in-cavity quantum state preparation, axion accumulation with tunable time duration, and measurement. For the quantum source, we focus on the single-mode squeezed state (SMSS), and the entanglement-assisted case using signal-ancilla pairs in two-mode squeezed state (TMSS), where the ancilla does not interact with the axion. From quantum Fisher information rate evaluation, we derive the requirement of cavity quality factor, thermal noise level and squeezing gain for quantum advantage. When the squeezing gain becomes larger, the optimal axion accumulation time decreases, which reduces loss and mitigates the Rayleigh curse—i.e., the quantum advantage increases with the squeezing gain. Overall, we find that TMSS is more sensitive in the low-temperature limit. In the case of SMSS, as large gain is required for an advantage over vacuum, homodyne detection is sufficient to achieve optimality. Whereas, for TMSS, anti-squeezing and photon counting is optimal. Thanks to recent advances in magnetic field-resilient in-cavity squeezing and rapidly coupling out for photon counting, the proposed protocol is compatible with axion detection scenario.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"61 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143641081","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

Halving the cost of quantum algorithms with randomization 用随机化将量子算法的成本减半

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-15 DOI: 10.1038/s41534-025-01003-2

John M. Martyn, Patrick Rall

{"title":"Halving the cost of quantum algorithms with randomization","authors":"John M. Martyn, Patrick Rall","doi":"10.1038/s41534-025-01003-2","DOIUrl":"https://doi.org/10.1038/s41534-025-01003-2","url":null,"abstract":"Quantum signal processing (QSP) provides a systematic framework for implementing a polynomial transformation of a linear operator, and unifies nearly all known quantum algorithms. In parallel, recent works have developed randomized compiling, a technique that promotes a unitary gate to a quantum channel and enables a quadratic suppression of error (i.e., ϵ → O(ϵ2)) at little to no overhead. Here we integrate randomized compiling into QSP through Stochastic Quantum Signal Processing. Our algorithm implements a probabilistic mixture of polynomials, strategically chosen so that the average evolution converges to that of a target function, with an error quadratically smaller than that of an equivalent individual polynomial. Because nearly all QSP-based algorithms exhibit query complexities scaling as (O(log (1/epsilon )))—stemming from a result in functional analysis—this error suppression reduces their query complexity by a factor that asymptotically approaches 1/2. By the unifying capabilities of QSP, this reduction extends broadly to quantum algorithms, which we demonstrate on algorithms for real and imaginary time evolution, phase estimation, ground state preparation, and matrix inversion.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"55 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631260","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

Microwave-coupled optical bistability in driven and interacting Rydberg gases

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-12 DOI: 10.1038/s41534-025-00997-z

Zhehua Zhang, Zeyan Zhang, Shaoxing Han, Yuqing Zhang, Guoqing Zhang, Jizhou Wu, Vladimir B. Sovkov, Wenliang Liu, Yuqing Li, Linjie Zhang, Liantuan Xiao, Suotang Jia, Weibin Li, Jie Ma

引用次数: 0

Quantum Zeno Monte Carlo for computing observables

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-12 DOI: 10.1038/s41534-025-01002-3

Mancheon Han, Hyowon Park, Sangkook Choi

引用次数: 0

Nearly quantum-limited microwave amplification via interfering degenerate stimulated emission in a single artificial atom

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-12 DOI: 10.1038/s41534-025-00993-3

Fahad Aziz, Kuan-Ting Lin, Ping-Yi Wen, Samina, Yu-Chen Lin, Emely Weigand, Ching-Ping Lee, Yu-Ting Cheng, Yong Lu, Ching-Yeh Chen, Chin-Hsun Chien, Kai-Min Hsieh, Yu-Huan Huang, Haw-Tyng Huang, Hou Ian, Jeng-Chung Chen, Yen-Hsiang Lin, Anton Frisk Kockum, Guin-Dar Lin, Io-Chun Hoi

{"title":"Nearly quantum-limited microwave amplification via interfering degenerate stimulated emission in a single artificial atom","authors":"Fahad Aziz, Kuan-Ting Lin, Ping-Yi Wen, Samina, Yu-Chen Lin, Emely Weigand, Ching-Ping Lee, Yu-Ting Cheng, Yong Lu, Ching-Yeh Chen, Chin-Hsun Chien, Kai-Min Hsieh, Yu-Huan Huang, Haw-Tyng Huang, Hou Ian, Jeng-Chung Chen, Yen-Hsiang Lin, Anton Frisk Kockum, Guin-Dar Lin, Io-Chun Hoi","doi":"10.1038/s41534-025-00993-3","DOIUrl":"https://doi.org/10.1038/s41534-025-00993-3","url":null,"abstract":"Reaching the quantum limit for added noise in amplification processes is an important step toward many quantum technologies. Nearly quantum-limited traveling-wave parametric amplifiers with Josephson junction arrays have been developed and recently even become commercially available. However, the fundamental question of whether a single atom also can reach this quantum limit has not yet been answered in practice. Here, we investigate the amplification of a microwave probe signal by a superconducting artificial atom, a transmon, at the end of a semi-infinite transmission line, under a strong pump field. The end of the transmission line acts as a mirror for microwave fields. Due to the weak anharmonicity of the artificial atom, the strong pump field creates multi-photon excitations among the dressed states. Transitions between these dressed states, Rabi sidebands, give rise to either amplification or attenuation of the weak probe. We obtain a maximum power amplification of 1.402 ± 0.025, higher than in any previous experiment with a single artificial atom. We achieve near-quantum-limited added noise (0.157 ± 0.003 quanta; the quantum limit is 0.143 ± 0.006 quanta for this level of amplification), due to quantum coherence between Rabi sidebands, leading to constructive interference between emitted photons.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"30 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599516","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

Uncovering quantum many-body scars with quantum machine learning

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2025-03-11 DOI: 10.1038/s41534-025-01005-0

Jia-Jin Feng, Bingzhi Zhang, Zhi-Cheng Yang, Quntao Zhuang

{"title":"Uncovering quantum many-body scars with quantum machine learning","authors":"Jia-Jin Feng, Bingzhi Zhang, Zhi-Cheng Yang, Quntao Zhuang","doi":"10.1038/s41534-025-01005-0","DOIUrl":"https://doi.org/10.1038/s41534-025-01005-0","url":null,"abstract":"Quantum many-body scars are rare eigenstates hidden within the chaotic spectra of many-body systems, representing a weak violation of the eigenstate thermalization hypothesis (ETH). Identifying these scars, as well as other non-thermal states in complex quantum systems, remains a significant challenge. Besides exact scar states, the nature of other non-thermal states lacking simple analytical characterization remains an open question. In this study, we employ tools from quantum machine learning—specifically, (enhanced) quantum convolutional neural networks (QCNNs), to explore hidden non-thermal states in chaotic many-body systems. Our simulations demonstrate that QCNNs achieve over 99% single-shot measurement accuracy in identifying all known scars. Furthermore, we successfully identify new non-thermal states in models such as the xorX model, the PXP model, and the far-coupling Su-Schrieffer-Heeger model. In the xorX model, some of these non-thermal states can be approximately described as spin-wave modes of specific quasiparticles. We further develop effective tight-binding Hamiltonians within the quasiparticle subspace to capture key features of these many-body eigenstates. Finally, we validate the performance of QCNNs on IBM quantum devices, achieving single-shot measurement accuracy exceeding 63% under real-world noise and errors, with the aid of error mitigation techniques. Our results underscore the potential of QCNNs to uncover hidden non-thermal states in quantum many-body systems.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"56 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143589661","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