Quantum Science and Technology最新文献

The role of higher-order terms in trapped-ion quantum computing with magnetic gradient induced coupling

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-03-30 DOI: 10.1088/2058-9565/adc1fe

Sebastian Nagies, Kevin T Geier, Javed Akram, Junichi Okamoto, Dimitrios Bantounas, Christof Wunderlich, Michael Johanning and Philipp Hauke

{"title":"The role of higher-order terms in trapped-ion quantum computing with magnetic gradient induced coupling","authors":"Sebastian Nagies, Kevin T Geier, Javed Akram, Junichi Okamoto, Dimitrios Bantounas, Christof Wunderlich, Michael Johanning and Philipp Hauke","doi":"10.1088/2058-9565/adc1fe","DOIUrl":"https://doi.org/10.1088/2058-9565/adc1fe","url":null,"abstract":"Trapped-ion hardware based on the magnetic gradient induced coupling (MAGIC) scheme is emerging as a promising platform for quantum computing. Nevertheless, in this—as in any other—quantum-computing platform, many technical questions still have to be resolved before large-scale and error-tolerant applications are possible. In this work, we present a thorough discussion of the structure and effects of higher-order terms in the MAGIC setup, which can occur due to anharmonicities in the external potential of the ion crystal (e.g. through Coulomb repulsion) or through curvature of the applied magnetic field. These terms generate systematic shifts in the leading-order interactions and take the form of three-spin couplings, two-spin couplings, local fields, as well as diverse phonon–phonon conversion mechanisms. We find that most of these are negligible in realistic situations, with only two contributions that need careful attention. First, there are undesired longitudinal fields contributing shifts to the resonance frequency, whose strength increases with chain length and phonon occupation numbers; while their mean effect can easily be compensated by additional Z rotations, phonon number fluctuations need to be avoided for precise gate operations. Second, anharmonicities of the Coulomb interaction can lead to well-known two-to-one conversions of phonon excitations. Both of these error terms can be mitigated by sufficiently cooling the phonons to the ground-state. Our detailed analysis constitutes an important contribution on the way of making magnetic-gradient trapped-ion quantum technology fit for large-scale applications, and it may inspire new ways to purposefully design interaction terms.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"31 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143736738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 memristive neural decoder for cryogenic fault-tolerant quantum error correction

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-03-28 DOI: 10.1088/2058-9565/adc3ba

Victor Yon, Frédéric Marcotte, Pierre-Antoine Mouny, Gebremedhin A Dagnew, Bohdan Kulchytskyy, Sophie Rochette, Yann Beilliard, Dominique Drouin and Pooya Ronagh

{"title":"A memristive neural decoder for cryogenic fault-tolerant quantum error correction","authors":"Victor Yon, Frédéric Marcotte, Pierre-Antoine Mouny, Gebremedhin A Dagnew, Bohdan Kulchytskyy, Sophie Rochette, Yann Beilliard, Dominique Drouin and Pooya Ronagh","doi":"10.1088/2058-9565/adc3ba","DOIUrl":"https://doi.org/10.1088/2058-9565/adc3ba","url":null,"abstract":"Neural decoders for quantum error correction rely on neural networks to classify syndromes extracted from error correction codes and find appropriate recovery operators to protect logical information against errors. Its ability to adapt to hardware noise and long-term drifts make neural decoders promising candidates for inclusion in a fault-tolerant quantum architecture. However, given their limited scalability, it is prudent that small-scale (local) neural decoders are treated as first stages of multi-stage decoding schemes for fault-tolerant quantum computers with millions of qubits. In this case, minimizing the decoding time to match the stabilization measurements frequency and a tight co-integration with the QPUs is highly desired. Cryogenic realizations of neural decoders can not only improve the performance of higher stage decoders, but they can minimize communication delays, and alleviate wiring bottlenecks. In this work, we design and analyze a neural decoder based on an in-memory computation (IMC) architecture, where crossbar arrays of resistive memory devices are employed to both store the synaptic weights of the neural decoder and perform analog matrix–vector multiplications. In simulations supported by experimental measurements, we investigate the impact of TiOx-based memristive devices’ non-idealities on decoding fidelity. We develop hardware-aware re-training methods to mitigate the fidelity loss, restoring the ideal decoder’s pseudo-threshold for the distance-3 surface code. This work provides a pathway to scalable, fast, and low-power cryogenic IMC hardware for integrated fault-tolerant quantum error correction.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"57 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 simulation of boson-related Hamiltonians: techniques, effective Hamiltonian construction, and error analysis

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-03-28 DOI: 10.1088/2058-9565/adbf42

Bo Peng, Yuan Su, Daniel Claudino, Karol Kowalski, Guang Hao Low and Martin Roetteler

{"title":"Quantum simulation of boson-related Hamiltonians: techniques, effective Hamiltonian construction, and error analysis","authors":"Bo Peng, Yuan Su, Daniel Claudino, Karol Kowalski, Guang Hao Low and Martin Roetteler","doi":"10.1088/2058-9565/adbf42","DOIUrl":"https://doi.org/10.1088/2058-9565/adbf42","url":null,"abstract":"Elementary quantum mechanics proposes that a closed physical system consistently evolves in a reversible manner. However, control and readout necessitate the coupling of the quantum system to the external environment, subjecting it to relaxation and decoherence. Consequently, system-environment interactions are indispensable for simulating physically significant theories. A broad spectrum of physical systems in condensed-matter and high-energy physics, vibrational spectroscopy, and circuit and cavity QED necessitates the incorporation of bosonic degrees of freedom, such as phonons, photons, and gluons, into optimized fermion algorithms for near-future quantum simulations. In particular, when a quantum system is surrounded by an external environment, its basic physics can usually be simplified to a spin or fermionic system interacting with bosonic modes. Nevertheless, troublesome factors such as the magnitude of the bosonic degrees of freedom typically complicate the direct quantum simulation of these interacting models, necessitating the consideration of a comprehensive plan. This strategy should specifically include a suitable fermion/boson-to-qubit mapping scheme to encode sufficiently large yet manageable bosonic modes, and a method for truncating and/or downfolding the Hamiltonian to the defined subspace for performing an approximate but highly accurate simulation, guided by rigorous error analysis. In this pedagogical tutorial review, we aim to provide such an exhaustive strategy, focusing on encoding and simulating certain bosonic-related model Hamiltonians, inclusive of their static properties and time evolutions. Specifically, we emphasize two aspects: (1) the discussion of recently developed quantum algorithms for these interacting models and the construction of effective Hamiltonians, and (2) a detailed analysis regarding a tightened error bound for truncating the bosonic modes for a class of fermion-boson interacting Hamiltonians.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"10 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Subspace preserving quantum convolutional neural network architectures

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-03-28 DOI: 10.1088/2058-9565/adbf43

Léo Monbroussou, Jonas Landman, Letao Wang, Alex B Grilo and Elham Kashefi

{"title":"Subspace preserving quantum convolutional neural network architectures","authors":"Léo Monbroussou, Jonas Landman, Letao Wang, Alex B Grilo and Elham Kashefi","doi":"10.1088/2058-9565/adbf43","DOIUrl":"https://doi.org/10.1088/2058-9565/adbf43","url":null,"abstract":"Subspace preserving quantum circuits are a class of quantum algorithms that, relying on some symmetries in the computation, can offer theoretical guarantees for their training. Those algorithms have gained extensive interest as they can offer polynomial speed-up and can be used to mimic classical machine learning algorithms. In this work, we propose a novel convolutional neural network architecture model based on Hamming weight (HW) preserving quantum circuits. In particular, we introduce convolutional layers, and measurement based pooling layers that preserve the symmetries of the quantum states while realizing non-linearity using gates that are not subspace preserving. Our proposal offers significant polynomial running time advantages over classical deep-learning architecture. We provide an open source simulation library for HW preserving quantum circuits that can simulate our techniques more efficiently with GPU-oriented libraries. Using this code, we provide examples of architectures that highlight great performances on complex image classification tasks with a limited number of qubits, and with fewer parameters than classical deep-learning architectures.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"1 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Trade-off between information gain and disturbance in local discrimination of entangled quantum states

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-03-27 DOI: 10.1088/2058-9565/adc034

Youngrong Lim, Minki Hhan and Hyukjoon Kwon

{"title":"Trade-off between information gain and disturbance in local discrimination of entangled quantum states","authors":"Youngrong Lim, Minki Hhan and Hyukjoon Kwon","doi":"10.1088/2058-9565/adc034","DOIUrl":"https://doi.org/10.1088/2058-9565/adc034","url":null,"abstract":"We establish an information gain-disturbance trade-off relation in local state discrimination. Our result demonstrates a fundamental limitation of local strategy to discriminate entangled quantum states without disturbance, which becomes more difficult as the entanglement of the states to be discriminated increases. For a set of maximally entangled states (MESs), the capability of local strategy is tightly suppressed, as random guessing without measurements saturates the bound provided by the trade-off relation. We also show that the trade-off can be circumvented when local operations are aided by pre-shared entanglement. To simultaneously achieve correct guessing of state and non-disturbance, an entirely different strategy from conventional state discrimination should be adopted to lower the cost of pre-shared entanglement. We explicitly propose an adaptive and non-destructive strategy based on the stabilizer formalism, which shows a strict advantage over conventional teleportation-based approaches in pre-shared entanglement cost for discriminating a set of MESs. As an application of the trade-off relation, we propose an entanglement certification protocol that is robust against depolarizing noise and generalize it to multipartite scenarios in a quantum network.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"99 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143712827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Artificially intelligent Maxwell’s demon for optimal control of open quantum systems

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-03-27 DOI: 10.1088/2058-9565/adbccf

Paolo A Erdman, Robert Czupryniak, Bibek Bhandari, Andrew N Jordan, Frank Noé, Jens Eisert and Giacomo Guarnieri

{"title":"Artificially intelligent Maxwell’s demon for optimal control of open quantum systems","authors":"Paolo A Erdman, Robert Czupryniak, Bibek Bhandari, Andrew N Jordan, Frank Noé, Jens Eisert and Giacomo Guarnieri","doi":"10.1088/2058-9565/adbccf","DOIUrl":"https://doi.org/10.1088/2058-9565/adbccf","url":null,"abstract":"Feedback control of open quantum systems is of fundamental importance for practical applications in various contexts, ranging from quantum computation to quantum error correction and quantum metrology. Its use in the context of thermodynamics further enables the study of the interplay between information and energy. However, deriving optimal feedback control strategies is highly challenging, as it involves the optimal control of open quantum systems, the stochastic nature of quantum measurement, and the inclusion of policies that maximize a long-term time- and trajectory-averaged goal. In this work, we employ a reinforcement learning approach to automate and capture the role of a quantum Maxwell’s demon: the agent takes the literal role of discovering optimal feedback control strategies in qubit-based systems that maximize a trade-off between measurement-powered cooling and measurement efficiency. Considering weak or projective quantum measurements, we explore different regimes based on the ordering between the thermalization, the measurement, and the unitary feedback timescales, finding different and highly non-intuitive, yet interpretable, strategies. In the thermalization-dominated regime, we find strategies with elaborate finite-time thermalization protocols conditioned on measurement outcomes. In the measurement-dominated regime, we find that optimal strategies involve adaptively measuring different qubit observables reflecting the acquired information, and repeating multiple weak measurements until the quantum state is ‘sufficiently pure’, leading to random walks in state space. Finally, we study the case when all timescales are comparable, finding new feedback control strategies that considerably outperform more intuitive ones. We discuss a two-qubit example where we explore the role of entanglement and conclude discussing the scaling of our results to quantum many-body systems.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"35 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143712825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Extractable energy from quantum superposition of current states

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-03-27 DOI: 10.1088/2058-9565/adbf45

Francesco Perciavalle, Davide Rossini, Juan Polo and Luigi Amico

引用次数: 0

Measurement of the work statistics of an open quantum system using a quantum computer

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-03-26 DOI: 10.1088/2058-9565/adbd6c

Lindsay Bassman Oftelie and Michele Campisi

引用次数: 0

Robust ultra-shallow shadows

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-03-25 DOI: 10.1088/2058-9565/adc14f

Renato M S Farias, Raghavendra D Peddinti, Ingo Roth and Leandro Aolita

{"title":"Robust ultra-shallow shadows","authors":"Renato M S Farias, Raghavendra D Peddinti, Ingo Roth and Leandro Aolita","doi":"10.1088/2058-9565/adc14f","DOIUrl":"https://doi.org/10.1088/2058-9565/adc14f","url":null,"abstract":"We present a robust shadow estimation protocol for wide classes of low-depth measurement circuits that mitigates noise as long as the effective measurement map including noise is locally unitarily invariant. This is in practice an excellent approximation, encompassing for instance the case of ideal single-qubit Clifford gates composing the first circuit layer of an otherwise arbitrary circuit architecture and even non-Markovian, gate-dependent noise in the rest of the circuit. We argue that for weakly-correlated local noise, the measurement channel has an efficient matrix-product representation, and show how to estimate this directly from experimental data using tensor-network tools, eliminating the need for analytical or numeric calculations. We illustrate the relevance of our method with both numerics and proof-of-principle experiments on an IBM Quantum device. Numerically, we show that unmitigated shallow shadows with noisy circuits become more biased as the depth increases. In contrast, using the same number of samples, robust ultra-shallow shadows become more precise with increasing depth for relevant parameter regimes. The gain in sample efficiency is still limited by the noise per gate, resulting in an optimal circuit depth per noise level. Experimentally, we observe improved precision in two simple fidelity estimation tasks using five-qubit circuits with up to two layers of entangling gates, by about an order of magnitude. Under the practical constraints of current and near-term noisy quantum devices, our method maximally realizes the potential of shadow estimation with global rotations and identifies its fundamental limitations in the presence of noise.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"57 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Lossy compression based on polar codes for high throughput information reconciliation in CV-QKD systems

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2025-03-20 DOI: 10.1088/2058-9565/adbf41

Yameng Liu, Xue-Qin Jiang, Jisheng Dai, Han Hai and Peng Huang

{"title":"Lossy compression based on polar codes for high throughput information reconciliation in CV-QKD systems","authors":"Yameng Liu, Xue-Qin Jiang, Jisheng Dai, Han Hai and Peng Huang","doi":"10.1088/2058-9565/adbf41","DOIUrl":"https://doi.org/10.1088/2058-9565/adbf41","url":null,"abstract":"Information reconciliation (IR) is a crucial component in the post-processing stage of continuous-variable quantum key distribution (CV-QKD) systems. However, the requirement to process a large amount of information in IR has become the bottleneck of realizing high-throughput CV-QKD systems, and the phenomenon of classical channel overloads appears. To solve these issues, we first propose a lossy compression scheme based on polar codes for the Gaussian sequences, and then propose an efficient IR protocol by combining such a lossy compression. By compressing the Gaussian sequences obtained by Alice and Bob, the new proposed protocol reduces the amount of information to be processed in IR, effectively breaking the bottleneck of realizing high-throughput CV-QKD systems. Additionally, it reduces the information Alice and Bob need to transmit over classical channels, easing the classical channel load. The theoretical analysis conducted on the compression ratio of the protocol and throughput offers valuable guidance for IR. Simulations confirmed that the proposed protocol can achieve higher throughput over the other polar-code-based IR protocols.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":"118 1","pages":""},"PeriodicalIF":6.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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