npj Quantum Information最新文献

Hamiltonian dynamics on digital quantum computers without discretization error 数字量子计算机上的哈密顿动力学无离散化误差

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-09-07 DOI: 10.1038/s41534-024-00877-y

Etienne Granet, Henrik Dreyer

引用次数: 0

Engineered dissipation to mitigate barren plateaus 设计消散以缓解贫瘠高原

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-09-04 DOI: 10.1038/s41534-024-00875-0

Antonio Sannia, Francesco Tacchino, Ivano Tavernelli, Gian Luca Giorgi, Roberta Zambrini

引用次数: 0

MadQCI: a heterogeneous and scalable SDN-QKD network deployed in production facilities MadQCI：在生产设施中部署的异构、可扩展的 SDN-QKD 网络

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-09-02 DOI: 10.1038/s41534-024-00873-2

V. Martin, J. P. Brito, L. Ortíz, R. B. Méndez, J. S. Buruaga, R. J. Vicente, A. Sebastián-Lombraña, D. Rincón, F. Pérez, C. Sánchez, M. Peev, H. H. Brunner, F. Fung, A. Poppe, F. Fröwis, A. J. Shields, R. I. Woodward, H. Griesser, S. Roehrich, F. de la Iglesia, C. Abellán, M. Hentschel, J. M. Rivas-Moscoso, A. Pastor-Perales, J. Folgueira, D. López

{"title":"MadQCI: a heterogeneous and scalable SDN-QKD network deployed in production facilities","authors":"V. Martin, J. P. Brito, L. Ortíz, R. B. Méndez, J. S. Buruaga, R. J. Vicente, A. Sebastián-Lombraña, D. Rincón, F. Pérez, C. Sánchez, M. Peev, H. H. Brunner, F. Fung, A. Poppe, F. Fröwis, A. J. Shields, R. I. Woodward, H. Griesser, S. Roehrich, F. de la Iglesia, C. Abellán, M. Hentschel, J. M. Rivas-Moscoso, A. Pastor-Perales, J. Folgueira, D. López","doi":"10.1038/s41534-024-00873-2","DOIUrl":"https://doi.org/10.1038/s41534-024-00873-2","url":null,"abstract":"Current quantum key distribution (QKD) networks focus almost exclusively on transporting secret keys at the highest possible rate. Consequently, they are built as mostly fixed, ad hoc, logically, and physically isolated infrastructures designed to avoid any penalty to the quantum channel. This architecture is neither scalable nor cost-effective and future, real-world deployments will differ considerably. The structure of the MadQCI QKD network presented here is based on disaggregated components and modern paradigms especially designed for flexibility, upgradability, and facilitating the integration of QKD in the security and telecommunications-networks ecosystem. These underlying ideas have been tested by deploying many QKD systems from several manufacturers in a real-world, multi-tenant telecommunications network, installed in production facilities and sharing the infrastructure with commercial traffic. Different technologies have been used in different links to address the variety of situations and needs that arise in real networks, exploring a wide range of possibilities. Finally, a set of realistic use cases has been implemented to demonstrate the validity and performance of the network. The testing took place during a period close to three years, where most of the nodes were continuously active.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":null,"pages":null},"PeriodicalIF":7.6,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142118092","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

Beating one bit of communication with and without quantum pseudo-telepathy 有量子伪心灵感应和无量子伪心灵感应的比特通信

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-08-22 DOI: 10.1038/s41534-024-00874-1

István Márton, Erika Bene, Péter Diviánszky, Tamás Vértesi

{"title":"Beating one bit of communication with and without quantum pseudo-telepathy","authors":"István Márton, Erika Bene, Péter Diviánszky, Tamás Vértesi","doi":"10.1038/s41534-024-00874-1","DOIUrl":"https://doi.org/10.1038/s41534-024-00874-1","url":null,"abstract":"According to Bell’s theorem, certain entangled states cannot be simulated classically using local hidden variables (LHV). Suppose that we can augment LHV by some amount of classical communication. The question then arises as to how many bits are needed to simulate entangled states? There is very strong evidence that a single bit of communication is powerful enough to simulate projective measurements on any two-qubit entangled state. However, the problem of simulating measurements on higher-dimensional systems remains largely unexplored. In this study, we present Bell-like scenarios, even with three inputs per party, in which bipartite correlations resulting from measurements on higher-dimensional states cannot be simulated with a single bit of communication. We consider the case where the communication direction is fixed and the case where it is bidirectional. To this end, we introduce constructions based on parallel repetition of pseudo-telepathy games and an original algorithm based on branch-and-bound technique to compute the one-bit classical bound. Two copies of emblematic Bell expressions, such as the Magic square pseudo-telepathy game, prove to be particularly powerful, requiring a 16 × 16 state to beat the bidirectional one-bit classical bound, and look a promising candidate for implementation on an optical platform.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":null,"pages":null},"PeriodicalIF":7.6,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142042510","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

Coherence of a field gradient driven singlet-triplet qubit coupled to multielectron spin states in 28Si/SiGe 28Si/SiGe 中与多电子自旋态耦合的场梯度驱动单三重四比特的相干性

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-08-14 DOI: 10.1038/s41534-024-00869-y

Younguk Song, Jonginn Yun, Jehyun Kim, Wonjin Jang, Hyeongyu Jang, Jaemin Park, Min-Kyun Cho, Hanseo Sohn, Noritaka Usami, Satoru Miyamoto, Kohei M. Itoh, Dohun Kim

{"title":"Coherence of a field gradient driven singlet-triplet qubit coupled to multielectron spin states in 28Si/SiGe","authors":"Younguk Song, Jonginn Yun, Jehyun Kim, Wonjin Jang, Hyeongyu Jang, Jaemin Park, Min-Kyun Cho, Hanseo Sohn, Noritaka Usami, Satoru Miyamoto, Kohei M. Itoh, Dohun Kim","doi":"10.1038/s41534-024-00869-y","DOIUrl":"https://doi.org/10.1038/s41534-024-00869-y","url":null,"abstract":"Engineered spin-electric coupling enables spin qubits in semiconductor nanostructures to be manipulated efficiently and addressed individually. While synthetic spin-orbit coupling using a micromagnet is widely investigated for driving and entangling qubits based on single spins in silicon, the baseband control of encoded spin qubits with a micromagnet in isotopically purified silicon has been less well investigated. Here, we demonstrate fast singlet-triplet qubit oscillation (~100 MHz) in a gate-defined double quantum dot in 28Si/SiGe with an on-chip micromagnet with which we show the oscillation quality factor of an encoded spin qubit exceeding 580. The coherence time T2* is analyzed as a function of potential detuning and an external magnetic field. In weak magnetic fields, the coherence is limited by frequency-independent noise whose time scale is faster than the typical data acquisition time of ~100 ms, which limits the T2* below 1 μs in the ergodic limit. We present evidence of sizable and coherent coupling of the qubit with the spin states of a nearby quantum dot, demonstrating that appropriate spin-electric coupling may enable a charge-based two-qubit gate in a (1,1) charge configuration.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":null,"pages":null},"PeriodicalIF":7.6,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141980980","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

Mitigation of interfacial dielectric loss in aluminum-on-silicon superconducting qubits 减轻铝硅超导量子比特的界面介电损耗

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-08-14 DOI: 10.1038/s41534-024-00868-z

Janka Biznárová, Amr Osman, Emil Rehnman, Lert Chayanun, Christian Križan, Per Malmberg, Marcus Rommel, Christopher Warren, Per Delsing, August Yurgens, Jonas Bylander, Anita Fadavi Roudsari

{"title":"Mitigation of interfacial dielectric loss in aluminum-on-silicon superconducting qubits","authors":"Janka Biznárová, Amr Osman, Emil Rehnman, Lert Chayanun, Christian Križan, Per Malmberg, Marcus Rommel, Christopher Warren, Per Delsing, August Yurgens, Jonas Bylander, Anita Fadavi Roudsari","doi":"10.1038/s41534-024-00868-z","DOIUrl":"https://doi.org/10.1038/s41534-024-00868-z","url":null,"abstract":"We demonstrate aluminum-on-silicon planar transmon qubits with time-averaged T1 energy relaxation times of up to 270 μs, corresponding to Q = 5 million, and a highest observed value of 501 μs. Through materials analysis techniques and numerical simulations we investigate the dominant source of energy loss, and devise and demonstrate a strategy toward its mitigation. Growing aluminum films thicker than 300 nm reduces the presence of oxide, a known host of defects, near the substrate-metal interface, as confirmed by time-of-flight secondary ion mass spectrometry. A loss analysis of coplanar waveguide resonators shows that this results in a reduction of dielectric loss due to two-level system defects. The correlation between the enhanced performance of our devices and the film thickness is due to the aluminum growth in columnar structures of parallel grain boundaries: transmission electron microscopy shows larger grains in the thicker film, and consequently fewer grain boundaries containing oxide near the substrate-metal interface.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":null,"pages":null},"PeriodicalIF":7.6,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141980979","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

Enhancing the electron pair approximation with measurements on trapped-ion quantum computers 利用对困离子量子计算机的测量增强电子对近似性

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-08-13 DOI: 10.1038/s41534-024-00871-4

Luning Zhao, Qingfeng Wang, Joshua J. Goings, Kyujin Shin, Woomin Kyoung, Seunghyo Noh, Young Min Rhee, Kyungmin Kim

{"title":"Enhancing the electron pair approximation with measurements on trapped-ion quantum computers","authors":"Luning Zhao, Qingfeng Wang, Joshua J. Goings, Kyujin Shin, Woomin Kyoung, Seunghyo Noh, Young Min Rhee, Kyungmin Kim","doi":"10.1038/s41534-024-00871-4","DOIUrl":"https://doi.org/10.1038/s41534-024-00871-4","url":null,"abstract":"The electron pair approximation offers an efficient variational quantum eigensolver (VQE) approach for chemistry simulations on quantum computers. With the number of entangling gates scaling quadratically with system size and a constant measurement overhead, the orbital optimized unitary pair coupled cluster double (oo-upCCD) ansatz strikes a balance between accuracy and efficiency. However, the electron pair approximation prevents the method from achieving quantitative accuracy. To improve it, we explore the theory of second order perturbation (PT2) correction to oo-upCCD. PT2 accounts for the missing broken-pair contributions in oo-upCCD, while retaining its efficiencies. For molecular bond stretching and chemical reactions, the method significantly improves the predicted energy accuracy, reducing oo-upCCD’s error by up to 90%. On IonQ’s quantum computers, we find that the PT2 energy correction is highly noise-resilient. The predicted VQE-PT2 reaction energies are in excellent agreement with noise-free simulators after applying simple error mitigations solely on the VQE energies.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":null,"pages":null},"PeriodicalIF":7.6,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141980981","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

Loss-induced quantum nonreciprocity 损失引起的量子非互惠性

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-08-12 DOI: 10.1038/s41534-024-00870-5

Baijun Li, Yunlan Zuo, Le-Man Kuang, Hui Jing, Chaohong Lee

{"title":"Loss-induced quantum nonreciprocity","authors":"Baijun Li, Yunlan Zuo, Le-Man Kuang, Hui Jing, Chaohong Lee","doi":"10.1038/s41534-024-00870-5","DOIUrl":"https://doi.org/10.1038/s41534-024-00870-5","url":null,"abstract":"Attribute to their robustness against loss and external noise, nonreciprocal photonic devices hold great promise for applications in quantum information processing. Recent advancements have demonstrated that nonreciprocal optical transmission in linear systems can be achieved through the strategic introduction of loss. However, a crucial question remains unanswered: can loss be harnessed as a resource for generating nonreciprocal quantum correlations? Here, we take a counterintuitive stance by engineering loss to generate a vital form of nonreciprocal quantum correlations, termed nonreciprocal photon blockade. We examine a dissipative three-cavity system comprising two nonlinear cavities and a linear cavity. The interplay of loss and nonlinearity leads to a robust nonreciprocal single- and two-photon blockade, facilitated by destructive quantum interference. Furthermore, we demonstrate the tunability of this nonreciprocal photon blockade by manipulating the relative phase between the two nonlinear cavities. Remarkably, this allows for the reversal of the direction of nonreciprocity. Our study not only sheds a light on the concept of loss-engineered quantum nonreciprocity but also opens up a pathway for the design of quantum nonreciprocal photonic devices.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":null,"pages":null},"PeriodicalIF":7.6,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141973796","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

Scalable determination of multipartite entanglement in quantum networks 量子网络中多方位纠缠的可扩展测定

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-08-08 DOI: 10.1038/s41534-024-00867-0

Wei-Ting Kao, Chien-Ying Huang, Tung-Ju Tsai, Shih-Hsuan Chen, Sheng-Yan Sun, Yu-Cheng Li, Teh-Lu Liao, Chih-Sung Chuu, He Lu, Che-Ming Li

{"title":"Scalable determination of multipartite entanglement in quantum networks","authors":"Wei-Ting Kao, Chien-Ying Huang, Tung-Ju Tsai, Shih-Hsuan Chen, Sheng-Yan Sun, Yu-Cheng Li, Teh-Lu Liao, Chih-Sung Chuu, He Lu, Che-Ming Li","doi":"10.1038/s41534-024-00867-0","DOIUrl":"https://doi.org/10.1038/s41534-024-00867-0","url":null,"abstract":"Quantum networks comprised of entangled end nodes serve stronger than the classical correlation for unparalleled quantum internet applications. However, practical quantum networking is affected by noise, which at its worst, causes end nodes to be described by pre-existing classical data. In such untrusted networks, determining quantum network fidelity and genuine multi-node entanglement becomes crucial. Here, we show that determining quantum network fidelity and genuine N-node entanglement in an untrusted star network requires only N + 1 measurement settings. This method establishes a semi-trusted framework, allowing some nodes to relax their assumptions. Our network determination method is enabled by detecting genuine N-node Einstein-Podolsky-Rosen steerability. Experimentally, using spontaneous parametric down-conversion entanglement sources, we demonstrate the determinations of genuine 3-photon and 4-photon quantum networks and the false positives of the widely used entanglement witness, the fidelity criterion of 1/2. Our results provide a scalable method for the determination of multipartite entanglement in realistic quantum networks.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":null,"pages":null},"PeriodicalIF":7.6,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141904627","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

Information compression via hidden subgroup quantum autoencoders 通过隐藏子群量子自动编码器实现信息压缩

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-08-08 DOI: 10.1038/s41534-024-00865-2

Feiyang Liu, Kaiming Bian, Fei Meng, Wen Zhang, Oscar Dahlsten

{"title":"Information compression via hidden subgroup quantum autoencoders","authors":"Feiyang Liu, Kaiming Bian, Fei Meng, Wen Zhang, Oscar Dahlsten","doi":"10.1038/s41534-024-00865-2","DOIUrl":"https://doi.org/10.1038/s41534-024-00865-2","url":null,"abstract":"We design a quantum method for classical information compression that exploits the hidden subgroup quantum algorithm. We consider sequence data in a database with a priori unknown symmetries of the hidden subgroup type. We prove that data with a given group structure can be compressed with the same query complexity as the hidden subgroup problem, which is exponentially faster than the best-known classical algorithms. We moreover design a quantum algorithm that variationally finds the group structure and uses it to compress the data. There is an encoder and a decoder, along the paradigm of quantum autoencoders. After the training, the encoder outputs a compressed data string and a description of the hidden subgroup symmetry, from which the input data can be recovered by the decoder. In illustrative examples, our algorithm outperforms the classical autoencoder on the mean squared value of test data. This classical-quantum separation in information compression capability has thermodynamical significance: the free energy assigned by a quantum agent to a system can be much higher than that of a classical agent. Taken together, our results show that a possible application of quantum computers is to efficiently compress certain types of data that cannot be efficiently compressed by current methods using classical computers.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":null,"pages":null},"PeriodicalIF":7.6,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141909206","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