npj Quantum Information最新文献

Near-term fermionic simulation with subspace noise tailored quantum error mitigation 近期费米子模拟与子空间噪声定制的量子误差缓解

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-04-24 DOI: 10.1038/s41534-026-01248-5

Miha Papič, Manuel G. Algaba, Emiliano Godinez-Ramirez, Inés de Vega, Adrian Auer, Fedor Šimkovic IV, Alessio Calzona

{"title":"Near-term fermionic simulation with subspace noise tailored quantum error mitigation","authors":"Miha Papič, Manuel G. Algaba, Emiliano Godinez-Ramirez, Inés de Vega, Adrian Auer, Fedor Šimkovic IV, Alessio Calzona","doi":"10.1038/s41534-026-01248-5","DOIUrl":"https://doi.org/10.1038/s41534-026-01248-5","url":null,"abstract":"Quantum error mitigation (QEM) has emerged as a powerful tool for the extraction of useful quantum information from quantum devices. Here, we introduce the Subspace Noise Tailoring (SNT) algorithm, which efficiently combines the cheap cost of Symmetry Verification (SV) and low bias of Probabilistic Error Cancellation (PEC) QEM techniques. We study the performance of our method by simulating the Trotterized time evolution of the spin-1/2 Fermi-Hubbard model (FHM) using a variety of local fermion-to-qubit encodings, which define a computational subspace through a set of stabilizers, the measurement of which can be used to post-select noisy quantum data. We study different combinations of QEM and encodings and uncover a rich state diagram of optimal combinations, depending on the hardware performance, system size and available shot budget. We then demonstrate how SNT extends the reach of current noisy quantum computers in terms of the number of fermionic lattice sites and the number of Trotter steps, and quantify the required hardware performance beyond which a noisy device may compete with current state-of-the-art classical computational methods.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"69 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147751802","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

Efficient post-selection for general quantum LDPC Codes 通用量子LDPC码的高效后选择

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-04-24 DOI: 10.1038/s41534-026-01242-x

Seok-Hyung Lee, Lucas H. English, Stephen D. Bartlett

{"title":"Efficient post-selection for general quantum LDPC Codes","authors":"Seok-Hyung Lee, Lucas H. English, Stephen D. Bartlett","doi":"10.1038/s41534-026-01242-x","DOIUrl":"https://doi.org/10.1038/s41534-026-01242-x","url":null,"abstract":"Post-selection strategies that discard low-confidence results can significantly improve the effective fidelity of quantum computing at the cost of reduced acceptance rates, particularly useful for offline resource state generation and moderate-depth fault-tolerant circuits. Prior work has primarily relied on the “logical gap” metric, which faces fundamental limitations including computational overhead that scales exponentially with the number of logical qubits and poor generalizability beyond surface codes. We develop post-selection strategies based on computationally efficient heuristic metrics that leverage error cluster statistics from clustering-based decoders, which are applicable to arbitrary quantum low-density parity check (QLDPC) codes. We validate our method through extensive numerical simulations on surface codes, bivariate bicycle codes, and hypergraph product codes, demonstrating orders of magnitude reductions in logical error rates with moderate abort rates. For instance, applying our strategy to the [[144, 12, 12]] bivariate bicycle code achieves ~ 1000 × reduction in the logical error rate with an abort rate of only 1% at a physical error rate of 0.1%. Additionally, we integrate our approach with the sliding-window framework for real-time decoding, featuring mid-circuit abort decisions that eliminate unnecessary overheads. Notably, its performance matches or even surpasses the original strategy, while exhibiting favorable scaling in the number of rounds.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"26 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147751806","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

Placing and routing quantum LDPC codes in multilayer superconducting hardware 量子LDPC码在多层超导硬件中的放置和路由

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-04-24 DOI: 10.1038/s41534-026-01243-w

Melvin Mathews, Lukas Pahl, David Pahl, Vaishnavi L. Addala, Catherine Tang, William D. Oliver, Jeffrey A. Grover

引用次数: 0

Surface-code hardware Hamiltonian 表面代码硬件哈密顿量

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-04-22 DOI: 10.1038/s41534-026-01241-y

Xuexin Xu, Kuljeet Kaur, Chloé Vignes, John M. Martinis, Mohammad H. Ansari

引用次数: 0

Distributed quantum inner product estimation with structured random circuits 基于结构随机电路的分布量子内积估计

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-04-21 DOI: 10.1038/s41534-026-01247-6

Congcong Zheng, Kun Wang, Xutao Yu, Ping Xu, Zaichen Zhang

{"title":"Distributed quantum inner product estimation with structured random circuits","authors":"Congcong Zheng, Kun Wang, Xutao Yu, Ping Xu, Zaichen Zhang","doi":"10.1038/s41534-026-01247-6","DOIUrl":"https://doi.org/10.1038/s41534-026-01247-6","url":null,"abstract":"Distributed inner product estimation (DIPE) is a fundamental task in quantum information, aiming to estimate the inner product between two unknown quantum states prepared on distributed quantum platforms. Existing rigorous sample complexity analyses are limited to unitary 4-designs, which pose significant practical challenges for near-term quantum devices. This work addresses this challenge by exploring DIPE with structured random circuits. We first establish that DIPE with an arbitrary unitary 2-design ensemble achieves an average sample complexity of ({mathcal{O}}(sqrt{{2}^{n}})), where n is the number of qubits. We then analyze ensembles below unitary 2-designs—specifically, the brickwork and local unitary 2-design ensembles—demonstrating average sample complexities of ({mathcal{O}}(sqrt{2.1{8}^{n}})) and ({mathcal{O}}(sqrt{2.{5}^{n}})), respectively. Furthermore, we analyze the state-dependent sample complexity. For brickwork ensembles, we develop a tensor network approach to compute the asymptotic state-dependent sample complexity, showing that it converges to ({mathcal{O}}(sqrt{2.1{8}^{n}})) as the circuit depth increases. Remarkably, we find that DIPE with the global Clifford ensemble requires (Theta (sqrt{{2}^{n}})) copies, matching the performance of unitary 4-designs. For both local and global Clifford ensembles, we find that the efficiency can be further enhanced by the nonstabilizerness of states. Additionally, for approximate unitary 4-designs, the performance exponentially approaches that of exact unitary 4-designs as the circuit depth increases. Our results provide theoretically guaranteed methods for implementing DIPE with experimentally feasible unitary ensembles.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"145 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147734037","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

Two-qubit gates using on-demand single-photons from ordered shape and size controlled large-volume superradiant quantum dots 使用来自有序形状和尺寸的按需单光子的双量子比特门控制大体积超辐射量子点

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-04-21 DOI: 10.1038/s41534-026-01221-2

Qi Huang, Swarnabha Chattaraj, Lucas Jordao, Jiefei Zhang, Siyuan Lu, Anupam Madhukar

{"title":"Two-qubit gates using on-demand single-photons from ordered shape and size controlled large-volume superradiant quantum dots","authors":"Qi Huang, Swarnabha Chattaraj, Lucas Jordao, Jiefei Zhang, Siyuan Lu, Anupam Madhukar","doi":"10.1038/s41534-026-01221-2","DOIUrl":"https://doi.org/10.1038/s41534-026-01221-2","url":null,"abstract":"At scale, fault tolerant on-chip photonic quantum information processing (P-QIP) has been hindered by the lack of (1) on-demand generation of millions of indistinguishable single photons as qubits from (2) quantum emitters in designed spatially ordered arrays. The demonstrated unique shape- and size-controlled mesa-top single quantum dots (MTSQDs) positioned with nm accuracy in designed arrays and exhibiting <2 nanometer spectral nonuniformity offer a promising solution. Here we report CNOT gates with ~90% fidelity using photons from individual MTSQDs at 4 K without Purcell enhancement that enable generating Bell states with fidelity of 0.825 ± 0.010, both underpinned by a two-photon interference (TPI) visibility 0.945 ± 0.005 and single photon purity > 99.5%. Temperature and power dependent studies reveal these remarkable figures-of-merit to originate in single photon superradiance and weak electron-phonon coupling unique to large volume MTSQDs giving large oscillator strength ( ~ 30) thus robustness against temperature. These results show a path to utility scale P-QIP platforms utilizing MTSQD arrays.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"136 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147734036","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

Collective purification of interacting quantum networks beyond symmetry constraints 超越对称约束的相互作用量子网络的集体净化

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-04-17 DOI: 10.1038/s41534-026-01228-9

Saikat Sur, Pritam Chattopadhyay, Arnab Chakrabarti, Nikolaos E. Palaiodimopoulos, Özgür E. Müstecaplıoğlu, Amit Finkler, Durga Bhaktavatsala Rao Dasari, Gershon Kurizki

{"title":"Collective purification of interacting quantum networks beyond symmetry constraints","authors":"Saikat Sur, Pritam Chattopadhyay, Arnab Chakrabarti, Nikolaos E. Palaiodimopoulos, Özgür E. Müstecaplıoğlu, Amit Finkler, Durga Bhaktavatsala Rao Dasari, Gershon Kurizki","doi":"10.1038/s41534-026-01228-9","DOIUrl":"https://doi.org/10.1038/s41534-026-01228-9","url":null,"abstract":"Following any quantum information processing protocol, it is essential to reset a mixed state of a many-body interacting spin-network to the computational-zero pure state. This task is challenging, both theoretically and experimentally, because of the quantum correlations. There is currently no effective cooling strategy for both high and low temperatures in such networks. Here we put forth a universal cooling strategy for multi-spin interacting networks. The strategy is based on the collective coupling of the system to an ancilla spin that intermittently dumps part of its entropy into an ultracold bath. Yet this strategy should overcome the symmetry-imposed correlations that impede the cooling. To avoid the prohibitive complexity of computing the dynamics, we resort to graph analysis of the network. We show that a unique choice of alternating, non-commuting system-ancilla interaction Hamiltonians exists that breaks the symmetry constraints and allows the network to approach the desired pure state. We illustrate this universal purification strategy in diverse experimental settings.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"22 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147709313","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

Beyond boson sampling: higher spin sampling as a practical path to quantum supremacy 超越玻色子采样：更高自旋采样作为量子霸权的实用途径

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-04-17 DOI: 10.1038/s41534-026-01246-7

Chon-Fai Kam, En-Jui Kuo

{"title":"Beyond boson sampling: higher spin sampling as a practical path to quantum supremacy","authors":"Chon-Fai Kam, En-Jui Kuo","doi":"10.1038/s41534-026-01246-7","DOIUrl":"https://doi.org/10.1038/s41534-026-01246-7","url":null,"abstract":"Since the dawn of quantum computation science, a range of quantum algorithms have been proposed, yet few have experimentally demonstrated a definitive quantum advantage. Shor’s algorithm, while renowned, has not been realized at a scale to outperform classical methods. In contrast, Fock-state boson sampling has been theoretically established, under standard complexity-theoretic assumptions, as a promising route toward quantum computational advantage. However, most existing experimental realizations of boson sampling to date have been based on Gaussian boson sampling, in which the input states consist of squeezed states of light. In this work, we introduce a higher-spin (S) sampling framework and show that it provides a practical path toward quantum computational advantage. We derive a quasi-linear scaling relation between the number of sites m and the number of spins n, namely m ~ n1+ϵ, where ϵ = 3/(2S) decreases with increasing spin quantum number. This suggests that, within a spin system, Fock-state boson sampling can be implemented in a quasi-linear mode regime (m = Ω(n1+ϵ)), significantly reducing experimental resource requirements.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"15 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147709310","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

Time-series forecasting with multiphoton quantum states and integrated photonics 多光子量子态和集成光子的时间序列预测

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-04-17 DOI: 10.1038/s41534-026-01236-9

Rosario Di Bartolo, Simone Piacentini, Francesco Ceccarelli, Giacomo Corrielli, Roberto Osellame, Valeria Cimini, Fabio Sciarrino

{"title":"Time-series forecasting with multiphoton quantum states and integrated photonics","authors":"Rosario Di Bartolo, Simone Piacentini, Francesco Ceccarelli, Giacomo Corrielli, Roberto Osellame, Valeria Cimini, Fabio Sciarrino","doi":"10.1038/s41534-026-01236-9","DOIUrl":"https://doi.org/10.1038/s41534-026-01236-9","url":null,"abstract":"Quantum machine learning algorithms have very recently attracted significant attention in photonic platforms. In particular, reconfigurable integrated photonic circuits offer a promising route, thanks to the possibility of implementing adaptive feedback loops, which are an essential ingredient for achieving the necessary nonlinear behavior characteristic of neural networks. Here, we implement a quantum reservoir computing protocol in which information is processed through a reconfigurable linear optical integrated photonic circuit and measured using single-photon detectors. We exploit a multiphoton-based setup for time-series forecasting tasks in a variety of scenarios, where the input signal is encoded in one of the circuit’s optical phases, thus modulating the quantum reservoir state. The resulting output probabilities are used to set the feedback phases and, at the end of the computation, are fed to a classical digital layer trained via linear regression to perform predictions. We then focus on the investigation of the role of input photon indistinguishability in the reservoir’s capabilities of predicting time-series. We experimentally demonstrate that two-photon indistinguishable input states lead to significantly better performance compared to distinguishable ones. This enhancement arises from the quantum correlations present in indistinguishable states, which enable the system to approximate higher-order nonlinear functions when using comparable physical resources, highlighting the importance of quantum interference and indistinguishability as a resource in photonic quantum reservoir computing.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"17 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147709311","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 reservoir computing induced by controllable damping 可控阻尼诱导的量子库计算

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2026-04-17 DOI: 10.1038/s41534-026-01229-8

Emanuele Ricci, Francesco Monzani, Luca Nigro, Enrico Prati

{"title":"Quantum reservoir computing induced by controllable damping","authors":"Emanuele Ricci, Francesco Monzani, Luca Nigro, Enrico Prati","doi":"10.1038/s41534-026-01229-8","DOIUrl":"https://doi.org/10.1038/s41534-026-01229-8","url":null,"abstract":"Quantum reservoir computing has emerged as a promising machine learning paradigm for processing temporal data on near-term quantum devices, as it exploits the large computational capacity of qubits without suffering from typical issues arising when training variational quantum circuits. In particular, quantum gate-based echo state networks have proven effective when the evolution of the reservoir circuit is non-unital. Nonetheless, a method for ensuring a tunable and stable non-unital circuit evolution was lacking. We propose an algorithm that induces damping by applying a controlled rotation to each qubit in the reservoir. It enables tunable, circuit-level amplitude amplification of the zero state, maintaining the system away from the maximally mixed state and preventing information loss caused by repeated mid-circuit measurements. The algorithm is inherently stable over time, as it can process arbitrarily long input sequences, beyond the coherence time of individual qubits, by inducing arbitrary damping on each qubit. Moreover, we show that quantum correlations between qubits improve memory retention, underscoring the potential utility of a quantum system as a computational reservoir. We demonstrate, through standard reservoir computing benchmarks, that this algorithm enables robust and scalable quantum random computing on fault-tolerant quantum hardware.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"23 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147709312","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