npj Quantum Information最新文献_第9页

Enhancing classical simulation with noisy quantum devices 用噪声量子器件增强经典模拟

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-07-02 DOI: 10.1038/s41534-026-01314-y

Ruiqi Zhang, Fuchuan Wei, Zhaohui Wei

引用次数: 0

Doubly-polylog-time-overhead fault-tolerant quantum computation by a polylog-time parallel minimum-weight perfect matching decoder 基于多对数时间并行最小权重完美匹配解码器的双多对数时间负载容错量子计算

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-07-02 DOI: 10.1038/s41534-026-01312-0

Yugo Takada, Hayata Yamasaki

{"title":"Doubly-polylog-time-overhead fault-tolerant quantum computation by a polylog-time parallel minimum-weight perfect matching decoder","authors":"Yugo Takada, Hayata Yamasaki","doi":"10.1038/s41534-026-01312-0","DOIUrl":"https://doi.org/10.1038/s41534-026-01312-0","url":null,"abstract":"Reducing space and time overheads of fault-tolerant quantum computation (FTQC) has received increasing attention as it is crucial for the development of quantum computers and plays a fundamental role in understanding the feasibility and limitations of realizing quantum advantages. Shorter time overheads are particularly essential for demonstrating quantum computational speedups without compromising runtime advantages. However, surpassing the conventional polylogarithmic (polylog) scaling of time overheads has remained a significant challenge, since it requires addressing all potential bottlenecks, including the nonzero runtime of classical computation for decoding in practical implementations. In this work, we construct a protocol that achieves FTQC with doubly polylog time overhead while maintaining the conventional polylog space overhead. The key to our approach is the development of a highly parallelizable minimum-weight perfect matching (MWPM) decoder, which achieves a polylog parallel runtime in the code size while providing theoretical guarantees on threshold existence and overhead bounds. Our protocol integrates this decoder with a topological-code protocol that incorporates single-shot decoding for efficient syndrome extraction; furthermore, we concatenate this with the concatenated Steane codes to guarantee the threshold while avoiding a backlog problem. These results suggest the feasibility of surpassing the conventional polylog-time-overhead barrier, opening a new frontier in low-overhead FTQC.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"7 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148385794","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

Gradiometric, fully tunable C-shunted flux qubits 梯度的，完全可调的c分流通量量子位

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-07-02 DOI: 10.1038/s41534-026-01295-y

B. Berlitz, A. Händel, E. Daum, A. V. Ustinov, J. Lisenfeld

引用次数: 0

A framework of partial error correction for intermediate-scale quantum computers 中等规模量子计算机部分纠错框架

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-07-01 DOI: 10.1038/s41534-026-01301-3

Nikolaos Koukoulekidis, Samson Wang, Tom O’Leary, Daniel Bultrini, Lukasz Cincio, Piotr Czarnik

{"title":"A framework of partial error correction for intermediate-scale quantum computers","authors":"Nikolaos Koukoulekidis, Samson Wang, Tom O’Leary, Daniel Bultrini, Lukasz Cincio, Piotr Czarnik","doi":"10.1038/s41534-026-01301-3","DOIUrl":"https://doi.org/10.1038/s41534-026-01301-3","url":null,"abstract":"As quantum computing hardware steadily increases in qubit count and quality, one important question is how to allocate these resources to mitigate the effects of hardware noise. In a transitional era between noisy small-scale and fully fault-tolerant systems, we envisage a scenario in which we are only able to error-correct a fraction of the qubits required to perform an interesting computation. In this work, we develop concrete constructions of logical operations on a joint system of a collection of noisy and a collection of error-corrected logical qubits. Within this setting and under Pauli noise assumptions, we provide analytic evidence that brick-layered circuits display on average slower concentration to the “useless” uniform distribution with increasing circuit depth compared to fully noisy circuits. We corroborate these findings by numerical demonstration of slower decoherence with an increasing fraction of error-corrected qubits under depolarizing noise acting at the circuit level. We find that this advantage only manifests when the number of error-corrected qubits passes a specified threshold which depends on the number of couplings between error-corrected and noisy registers.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"23 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148385797","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 context-aware gate set tomography: Improving the self-consistent characterization of trapped-ion universal gate sets by leveraging non-Markovianity 上下文感知门集断层扫描：利用非马尔可夫性改善捕获离子通用门集的自一致特性

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-06-26 DOI: 10.1038/s41534-026-01313-z

P. Viñas, A. Bermudez

{"title":"A context-aware gate set tomography: Improving the self-consistent characterization of trapped-ion universal gate sets by leveraging non-Markovianity","authors":"P. Viñas, A. Bermudez","doi":"10.1038/s41534-026-01313-z","DOIUrl":"https://doi.org/10.1038/s41534-026-01313-z","url":null,"abstract":"To progress in the characterization of noise for quantum computers, gate set tomography (GST) has emerged as a self-consistent protocol that accurately estimates noisy gates, state preparations, and measurements. In its original incarnation, GST improves estimation precision by applying gates sequentially, assuming the noise yields fixed completely-positive and trace-preserving (CPTP) maps independent of prior gate history. This ‘Markovian’ assumption can conflict with experiments, where time-correlated noise may induce non-Markovian dynamics, or slow drifts and cumulative calibration errors introduce context dependence, causing CP-divisible maps to vary with circuit depth. In this work, we address this issue for trapped-ion devices with phonon-mediated two-qubit gates. Using detailed microscopic modeling of high-fidelity light-shift gates, we tailor GST to capture the main source of context dependence: motional degrees of freedom. Rather than invalidating GST, context dependence can be incorporated into the gate-set parametrization, reducing sampling cost. Our results identify a promising research avenue that might be applicable to other platforms where microscopic modeling can be incorporated: the development of a context-aware GST.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"76 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148336440","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

Learning pure quantum states almost without regret 学习纯量子态几乎没有遗憾

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-06-26 DOI: 10.1038/s41534-026-01305-z

Josep Lumbreras, Mikhail Terekhov, Marco Tomamichel

引用次数: 0

Continuous-variable quantum key distribution with a leakage from digital-to-analog conversion 具有数模转换泄漏的连续变量量子密钥分配

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-06-25 DOI: 10.1038/s41534-026-01309-9

Xu Liu, Jinghan Sun, Tao Wang, Peng Huang, Guihua Zeng

{"title":"Continuous-variable quantum key distribution with a leakage from digital-to-analog conversion","authors":"Xu Liu, Jinghan Sun, Tao Wang, Peng Huang, Guihua Zeng","doi":"10.1038/s41534-026-01309-9","DOIUrl":"https://doi.org/10.1038/s41534-026-01309-9","url":null,"abstract":"In the field of quantum communication, investigating the practical security of systems is conducive to their deployments in real-world scenarios. In this paper, we identify and experimentally demonstrate a side-channel vulnerability within continuous-variable quantum key distribution (CV-QKD) arising from the zero-order hold (ZOH) effect in digital-to-analog conversion. As digital-to-analog converters (DACs) are indispensable for modulation in CV-QKD transmitters, this leakage constitutes an intrinsic and widespread risk. We show that the ZOH-induced spectral side lobes allow an eavesdropper to extract secret information without disturbing the main signal band. Experimental validation on a CV-QKD platform reveals a leakage of 2.68 Mbit/s against a generated secret key rate of 4.73 Mbit/s. Crucially, we propose a defense strategy that completely eliminates this vulnerability, effectively restoring the system’s implementation security. By resolving this fundamental hardware limitation, our work bridges the gap between theoretical models and practical engineering, paving the way for robust, standardized quantum communication networks.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"24 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148336441","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

Optimal control for Rydberg multi-qubit operations Rydberg多量子位运算的最优控制

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-06-25 DOI: 10.1038/s41534-026-01288-x

Mohammadsadegh Khazali, Hossein Abedi, Klaus Mølmer

引用次数: 0

Design and optimization of adaptive diversity schemes in quantum MIMO channels 量子MIMO信道自适应分集方案的设计与优化

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-06-24 DOI: 10.1038/s41534-026-01308-w

Shehbaz Tariq, Symeon Chatzinotas

{"title":"Design and optimization of adaptive diversity schemes in quantum MIMO channels","authors":"Shehbaz Tariq, Symeon Chatzinotas","doi":"10.1038/s41534-026-01308-w","DOIUrl":"https://doi.org/10.1038/s41534-026-01308-w","url":null,"abstract":"As quantum networks evolve toward a full quantum Internet, reliable transmission in quantum multiple-input multiple-output (QuMIMO) settings becomes essential, yet remains difficult due to noise, crosstalk, and the mixing of quantum information across subchannels. To improve reliability in such settings, we study an adaptive diversity strategy for discrete-variable QuMIMO systems based on universal asymmetric cloning at the transmitter and probabilistic purification at the receiver. An input qubit is encoded into M approximate clones, transmitted over an N × N multi-mode quantum channel, and recovered through a purification map optimized using available channel state information (CSI). For the given cloning asymmetry parameters, we derive an eigenvalue-based expression for the decoder-optimal end-to-end fidelity in the form of a generalized Rayleigh quotient, which enables efficient tuning of the cloner without iterative optimization. As a design choice, we employ semidefinite program (SDP) to construct the purification map for only a targeted success probability p. This numerical framework is used to study fixed-noise, dimension-scaling noise, and stochastic depolarization regimes. A cloning asymmetry index is introduced to quantify the distribution of quantum information across the multiple subchannels across these operating conditions. The results show that the proposed scheme yields significant fidelity gains in crosstalk-dominated settings and automatically adapts to channel symmetry and channel conditions. This work provides design guidelines for future QuMIMO systems and establishes a robust baseline for more advanced transmission and decoding strategies.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"71 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148336448","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

Fullqubit alchemist: quantum algorithm for alchemical free energy calculations 全量子位炼金术士：用于炼金自由能计算的量子算法

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-06-23 DOI: 10.1038/s41534-026-01275-2

Po-Wei Huang, Gregory Boyd, Gian-Luca R. Anselmetti, Matthias Degroote, Nikolaj Moll, Raffaele Santagati, Michael Streif, Benjamin Ries, Daniel Marti-Dafcik, Hamza Jnane, Sophia Simon, Nathan Wiebe, Thomas R. Bromley, Bálint Koczor

{"title":"Fullqubit alchemist: quantum algorithm for alchemical free energy calculations","authors":"Po-Wei Huang, Gregory Boyd, Gian-Luca R. Anselmetti, Matthias Degroote, Nikolaj Moll, Raffaele Santagati, Michael Streif, Benjamin Ries, Daniel Marti-Dafcik, Hamza Jnane, Sophia Simon, Nathan Wiebe, Thomas R. Bromley, Bálint Koczor","doi":"10.1038/s41534-026-01275-2","DOIUrl":"https://doi.org/10.1038/s41534-026-01275-2","url":null,"abstract":"Accurately computing the free energies of biological processes is a cornerstone of computer-aided drug design, but it is a daunting task. The need to sample vast conformational spaces and account for entropic contributions makes the estimation of binding free energies very expensive. While classical methods, such as thermodynamic integration and alchemical free energy calculations, have significantly contributed to reducing computational costs, they still face limitations in terms of efficiency and scalability. We tackle this through a quantum algorithm for the estimation of free energy differences by adapting the existing Liouvillian approach and introducing several key algorithmic improvements. We directly implement the Liouvillian operator and provide an efficient description of electronic forces acting on both nuclear and electronic particles on the quantum ground state potential energy surface. This leads to super-polynomial runtime scaling improvements in the precision of our Liouvillian simulation approach and quadratic improvements in the scaling with the number of particles relative to prior quantum algorithms. Second, our algorithm calculates free energy differences via a fully quantum implementation of thermodynamic integration and alchemy, thereby foregoing expensive entropy estimation subroutines used in prior works. Our results open new avenues towards the application of quantum computers in drug discovery.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"108 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148305420","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