Quantum最新文献_第5页

Quantum teleportation implies symmetry-protected topological order 量子瞬移意味着受对称保护的拓扑秩序

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-10-10 DOI: 10.22331/q-2024-10-10-1499

Yifan Hong, David T. Stephen, Aaron J. Friedman

引用次数: 0

Quantum-classical tradeoffs and multi-controlled quantum gate decompositions in variational algorithms 变分算法中的量子经典权衡和多控制量子门分解

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-10-04 DOI: 10.22331/q-2024-10-04-1493

Teague Tomesh, Nicholas Allen, Daniel Dilley, Zain Saleem

{"title":"Quantum-classical tradeoffs and multi-controlled quantum gate decompositions in variational algorithms","authors":"Teague Tomesh, Nicholas Allen, Daniel Dilley, Zain Saleem","doi":"10.22331/q-2024-10-04-1493","DOIUrl":"https://doi.org/10.22331/q-2024-10-04-1493","url":null,"abstract":"The computational capabilities of near-term quantum computers are limited by the noisy execution of gate operations and a limited number of physical qubits. Hybrid variational algorithms are well-suited to near-term quantum devices because they allow for a wide range of tradeoffs between the amount of quantum and classical resources used to solve a problem. This paper investigates tradeoffs available at both the algorithmic and hardware levels by studying a specific case – applying the Quantum Approximate Optimization Algorithm (QAOA) to instances of the Maximum Independent Set (MIS) problem. We consider three variants of the QAOA which offer different tradeoffs at the algorithmic level in terms of their required number of classical parameters, quantum gates, and iterations of classical optimization needed. Since MIS is a constrained combinatorial optimization problem, the QAOA must respect the problem constraints. This can be accomplished by using many multi-controlled gate operations which must be decomposed into gates executable by the target hardware. We study the tradeoffs available at this hardware level, combining the gate fidelities and decomposition efficiencies of different native gate sets into a single metric called the $textit{gate decomposition cost}$.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"10 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142374153","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

Differentiating and Integrating ZX Diagrams with Applications to Quantum Machine Learning 区分和整合 ZX 图表并将其应用于量子机器学习

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-10-04 DOI: 10.22331/q-2024-10-04-1491

Quanlong Wang, Richie Yeung, Mark Koch

引用次数: 0

Mixed-state additivity properties of magic monotones based on quantum relative entropies for single-qubit states and beyond 基于单量子比特态及其他量子相对熵的神奇单调的混态相加特性

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-10-04 DOI: 10.22331/q-2024-10-04-1492

Roberto Rubboli, Ryuji Takagi, Marco Tomamichel

引用次数: 0

Repeated measurements on non-replicable systems and their consequences for Unruh-DeWitt detectors 不可复制系统的重复测量及其对 Unruh-DeWitt 探测器的影响

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-10-03 DOI: 10.22331/q-2024-10-03-1490

Nicola Pranzini, Guillermo García-Pérez, Esko Keski-Vakkuri, Sabrina Maniscalco

{"title":"Repeated measurements on non-replicable systems and their consequences for Unruh-DeWitt detectors","authors":"Nicola Pranzini, Guillermo García-Pérez, Esko Keski-Vakkuri, Sabrina Maniscalco","doi":"10.22331/q-2024-10-03-1490","DOIUrl":"https://doi.org/10.22331/q-2024-10-03-1490","url":null,"abstract":"The Born rule describes the probability of obtaining an outcome when measuring an observable of a quantum system. As it can only be tested by measuring many copies of the system under consideration, it does not hold for non-replicable systems. For these systems, we give a procedure to predict the future statistics of measurement outcomes through Repeated Measurements (RM). This is done by extending the validity of quantum mechanics to those systems admitting no replicas; we prove that if the statistics of the results acquired by performing RM on such systems is sufficiently similar to that obtained by the Born rule, the latter can be used effectively. We apply our framework to a repeatedly measured Unruh-DeWitt detector interacting with a massless scalar quantum field, which is an example of a system (detector) interacting with an uncontrollable environment (field) for which using RM is necessary. Analysing what an observer learns from the RM outcomes, we find a regime where history-dependent RM probabilities are close to the Born ones. Consequently, the latter can be used for all practical purposes. Finally, we numerically study inertial and accelerated detectors, showing that an observer can see the Unruh effect via RM.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"49 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142374150","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

Topological photon pumping in quantum optical systems 量子光学系统中的拓扑光子泵浦

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-10-02 DOI: 10.22331/q-2024-10-02-1488

Mathias B. M. Svendsen, Marcel Cech, Max Schemmer, Beatriz Olmos

引用次数: 0

Quantum Multiple Eigenvalue Gaussian filtered Search: an efficient and versatile quantum phase estimation method 量子多特征值高斯滤波搜索：一种高效通用的量子相位估算方法

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-10-02 DOI: 10.22331/q-2024-10-02-1487

Zhiyan Ding, Haoya Li, Lin Lin, HongKang Ni, Lexing Ying, Ruizhe Zhang

引用次数: 0

(Almost-)Quantum Bell Inequalities and Device-Independent Applications (几乎）量子贝尔不等式和与设备无关的应用

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-10-02 DOI: 10.22331/q-2024-10-02-1489

Yuan Liu, Ho Yiu Chung, Ravishankar Ramanathan

{"title":"(Almost-)Quantum Bell Inequalities and Device-Independent Applications","authors":"Yuan Liu, Ho Yiu Chung, Ravishankar Ramanathan","doi":"10.22331/q-2024-10-02-1489","DOIUrl":"https://doi.org/10.22331/q-2024-10-02-1489","url":null,"abstract":"Investigations of the boundary of the quantum correlation set have gained increased attention in recent years. This is done through the derivation of quantum Bell inequalities, which are related to Tsirelson's problem and have significant applications in device-independent (DI) information processing. However, determining quantum Bell inequalities is a notoriously difficult task and only isolated examples are known. In this paper, we present families of (almost-)quantum Bell inequalities and highlight four foundational and DI applications. Firstly, it is known that quantum correlations on the non-signaling boundary are of crucial importance in the task of DI randomness extraction from weak sources. In the practical Bell scenario of two players with two $k$-outcome measurements, we derive quantum Bell inequalities that demonstrate a separation between the quantum boundary and certain portions of the boundaries of the no-signaling polytope of dimension up to $4k-8$, extending previous results from nonlocality distillation and the collapse of communication complexity. Secondly as an immediate by-product, we give a general proof of Aumann’s Agreement theorem for quantum systems as well as the almost-quantum correlations, which implies Aumann’s agreement theorem is a reasonable physical principle in the context of epistemics to pick out both quantum theory and almost-quantum correlations from general no-signaling theories. Thirdly, we present a family of quantum Bell inequalities in the two players with $m$ binary measurements scenarios, that we prove serve to self-test the two-qubit singlet and the corresponding $2m$ measurements. Interestingly, this claim generalizes the result for $m=2$ discovered by Tsirelson-Landau-Masanes and shows an improvement over the state-of-the-art Device-Independent Randomness-Amplification (DIRA). Lastly, we use our quantum Bell inequalities to derive the general form of the principle of no advantage in nonlocal computation, which is an information-theoretic principle that serves to characterize the quantum correlation set.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"111 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142363013","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

Stochastic Thermodynamics at the Quantum-Classical Boundary: A Self-Consistent Framework Based on Adiabatic-Response Theory 量子-经典边界的随机热力学：基于绝热响应理论的自洽框架

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-09-26 DOI: 10.22331/q-2024-09-26-1486

Joshua Eglinton, Federico Carollo, Igor Lesanovsky, Kay Brandner

{"title":"Stochastic Thermodynamics at the Quantum-Classical Boundary: A Self-Consistent Framework Based on Adiabatic-Response Theory","authors":"Joshua Eglinton, Federico Carollo, Igor Lesanovsky, Kay Brandner","doi":"10.22331/q-2024-09-26-1486","DOIUrl":"https://doi.org/10.22331/q-2024-09-26-1486","url":null,"abstract":"Microscopic thermal machines promise to play an important role in future quantum technologies. Making such devices widely applicable will require effective strategies to channel their output into easily accessible storage systems like classical degrees of freedom. Here, we develop a self-consistent theoretical framework that makes it possible to model such quantum-classical hybrid devices in a thermodynamically consistent manner. Our approach is based on the assumption that the quantum part of the device is subject to strong decoherence and dissipation induced by a thermal reservoir. Due to the ensuing separation of time scales between slowly evolving classical and fast relaxing quantum degrees of freedom, the dynamics of the hybrid system can be described by means of adiabatic-response theory. We show that, upon including fluctuations in a minimally consistent way, the resulting equations of motion can be equipped with a first and second law, both on the ensemble level and on the level of individual trajectories of the classical part of the system, where thermodynamic quantities like heat and work become stochastic variables. As an application of our theory, we work out a physically transparent model of a quantum-classical hybrid engine, whose working system consists of a chain of Rydberg atoms, which is confined in an optical cavity and driven by periodic temperature variations. We demonstrate through numerical simulations that the engine can sustain periodic oscillations of a movable mirror, which acts as a classical load, against external friction and extract the full distributions of input heat and output work. By making the statistics of thermodynamic processes in quantum-classical hybrid systems accessible without the need to further specify a measurement protocol, our work contributes to bridging the long-standing gap between classical and quantum stochastic thermodynamics.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"35 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142321724","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

Relating Wigner’s Friend Scenarios to Nonclassical Causal Compatibility, Monogamy Relations, and Fine Tuning 将维格纳的朋友情景与非经典因果相容、一夫一妻关系和微调联系起来

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-09-26 DOI: 10.22331/q-2024-09-26-1485

Yìlè Yīng, Marina Maciel Ansanelli, Andrea Di Biagio, Elie Wolfe, David Schmid, Eric Gama Cavalcanti

{"title":"Relating Wigner’s Friend Scenarios to Nonclassical Causal Compatibility, Monogamy Relations, and Fine Tuning","authors":"Yìlè Yīng, Marina Maciel Ansanelli, Andrea Di Biagio, Elie Wolfe, David Schmid, Eric Gama Cavalcanti","doi":"10.22331/q-2024-09-26-1485","DOIUrl":"https://doi.org/10.22331/q-2024-09-26-1485","url":null,"abstract":"Nonclassical causal modeling was developed in order to explain violations of Bell inequalities while adhering to relativistic causal structure and $faithfulness$---that is, avoiding fine-tuned causal explanations. Recently, a no-go theorem that can be viewed as being stronger than Bell's theorem has been derived, based on extensions of the Wigner's friend thought experiment: the Local Friendliness (LF) no-go theorem. Here we show that the LF no-go theorem poses formidable challenges for the field of causal modeling, even when nonclassical and/or cyclic causal explanations are considered. We first recast the LF inequalities, one of the key elements of the LF no-go theorem, as special cases of monogamy relations stemming from a statistical marginal problem. We then further recast LF inequalities as causal compatibility inequalities stemming from a $nonclassical$ causal marginal problem, for a causal structure implied by well-motivated causal-metaphysical assumptions. We find that the LF inequalities emerge from this causal structure even when one allows the latent causes of observed events to admit post-quantum descriptions, such as in a generalized probabilistic theory or in an even more exotic theory. We further prove that $no$ nonclassical causal model can explain violations of LF inequalities without violating the No Fine-Tuning principle. Finally, we note that these obstacles cannot be overcome even if one appeals to $cyclic$ causal models, and we discuss potential directions for further extensions of the causal modeling framework.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"17 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142321723","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