Quantum最新文献_第6页

An Effective Way to Determine the Separability of Quantum State 确定量子态可分性的一种有效方法

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-05-06 DOI: 10.22331/q-2025-05-06-1734

Ma-Cheng Yang, Cong-Feng Qiao

引用次数: 0

Multidimensional Electrical Networks and their Application to Exponential Speedups for Graph Problems 多维电网络及其在图问题指数加速中的应用

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-05-06 DOI: 10.22331/q-2025-05-06-1733

Jianqiang Li, Sebastian Zur

{"title":"Multidimensional Electrical Networks and their Application to Exponential Speedups for Graph Problems","authors":"Jianqiang Li, Sebastian Zur","doi":"10.22331/q-2025-05-06-1733","DOIUrl":"https://doi.org/10.22331/q-2025-05-06-1733","url":null,"abstract":"Recently, Apers and Piddock [TQC '23] strengthened the connection between quantum walks and electrical networks via Kirchhoff's Law and Ohm's Law. In this work, we develop a new multidimensional electrical network by defining Alternative Kirchhoff's Law and Alternative Ohm's Law based on the multidimensional quantum walk framework by Jeffery and Zur [STOC '23]. In analogy to the connection between the incidence matrix of a graph and Kirchhoff's Law and Ohm's Law in an electrical network, we rebuild the connection between the alternative incidence matrix and Alternative Kirchhoff's Law and Alternative Ohm's Law. This new framework enables generating an alternative electrical flow over the edges on graphs, which has the potential to be applied to a broader range of graph problems, benefiting both quantum and classical algorithm design.<br/> We first use this framework to generate quantum alternative electrical flow states and use it to find a marked vertex in one-dimensional random hierarchical graphs as defined by Balasubramanian, Li, and Harrow [arXiv '23]. In this work, they generalised the exponential quantum-classical separation of the welded tree graph by Childs, Cleve, Deotto, Farhi, Gutmann, and Spielman [STOC '03] to random hierarchical graphs. Our result partially recovers their results with an arguably simpler analysis.<br/> Furthermore, this framework also allows us to demonstrate an exponential quantum speedup for the pathfinding problem in a type of regular graph, which we name the welded tree circuit graph. The exponential quantum advantage is obtained by efficiently generating quantum alternative electrical flow states and then sampling from them to find an s-t path in the welded tree circuit graph. By comparison, Li [arXiv '23] constructed a non-regular graph based on welded trees and used the degree information to achieve a similar speedup.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"16 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143915958","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 network-entanglement measures 量子网络纠缠措施

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-05-06 DOI: 10.22331/q-2025-05-06-1736

Zhen-Peng Xu, Julio I. de Vicente, Liang-Liang Sun, Sixia Yu

引用次数: 0

A Quadratic Speedup in Finding Nash Equilibria of Quantum Zero-Sum Games 寻找量子零和博弈纳什均衡的二次加速

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-05-06 DOI: 10.22331/q-2025-05-06-1737

Francisca Vasconcelos, Emmanouil-Vasileios Vlatakis-Gkaragkounis, Panayotis Mertikopoulos, Georgios Piliouras, Michael I. Jordan

{"title":"A Quadratic Speedup in Finding Nash Equilibria of Quantum Zero-Sum Games","authors":"Francisca Vasconcelos, Emmanouil-Vasileios Vlatakis-Gkaragkounis, Panayotis Mertikopoulos, Georgios Piliouras, Michael I. Jordan","doi":"10.22331/q-2025-05-06-1737","DOIUrl":"https://doi.org/10.22331/q-2025-05-06-1737","url":null,"abstract":"Recent developments in domains such as non-local games, quantum interactive proofs, and quantum generative adversarial networks have renewed interest in quantum game theory and, specifically, quantum zero-sum games. Central to classical game theory is the efficient algorithmic computation of Nash equilibria, which represent optimal strategies for both players. In 2008, Jain and Watrous proposed the first classical algorithm for computing equilibria in quantum zero-sum games using the Matrix Multiplicative Weight Updates (MMWU) method to achieve a convergence rate of $mathcal{O}(d/epsilon^2)$ iterations to $epsilon$-Nash equilibria in the $4^d$-dimensional spectraplex. In this work, we propose a hierarchy of quantum optimization algorithms that generalize MMWU via an extra-gradient mechanism. Notably, within this proposed hierarchy, we introduce the Optimistic Matrix Multiplicative Weights Update (OMMWU) algorithm and establish its average-iterate convergence complexity as $mathcal{O}(d/epsilon)$ iterations to $epsilon$-Nash equilibria. This quadratic speed-up relative to Jain and Watrous' original algorithm sets a new benchmark for computing $epsilon$-Nash equilibria in quantum zero-sum games.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"95 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143915965","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

Fault-tolerant structures for measurement-based quantum computation on a network 基于测量的网络量子计算容错结构

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-05-05 DOI: 10.22331/q-2025-05-05-1723

Yves van Montfort, Sébastian de Bone, David Elkouss

{"title":"Fault-tolerant structures for measurement-based quantum computation on a network","authors":"Yves van Montfort, Sébastian de Bone, David Elkouss","doi":"10.22331/q-2025-05-05-1723","DOIUrl":"https://doi.org/10.22331/q-2025-05-05-1723","url":null,"abstract":"In this work, we introduce a method to construct fault-tolerant $textit{measurement-based quantum computation}$ (MBQC) architectures and numerically estimate their performance over various types of networks. A possible application of such a paradigm is distributed quantum computation, where separate computing nodes work together on a fault-tolerant computation through entanglement. We gauge error thresholds of the architectures with an efficient stabilizer simulator to investigate the resilience against both circuit-level and network noise. We show that, for both monolithic (i.e., non-distributed) and distributed implementations, an architecture based on the diamond lattice may outperform the conventional cubic lattice. Moreover, the high erasure thresholds of non-cubic lattices may be exploited further in a distributed context, as their performance may be boosted through $textit{entanglement distillation}$ by trading in entanglement success rates against erasure errors during the error-decoding process. These results highlight the significance of lattice geometry in the design of fault-tolerant measurement-based quantum computing on a network, emphasizing the potential for constructing robust and scalable distributed quantum computers.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"24 1","pages":"1723"},"PeriodicalIF":6.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143910402","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 geometrical description of non-Hermitian dynamics: speed limits in finite rank density operators 非厄米动力学的几何描述：有限秩密度算子中的速度限制

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-05-05 DOI: 10.22331/q-2025-05-05-1729

Niklas Hörnedal, Oskar A. Prośniak, Adolfo del Campo, Aurélia Chenu

引用次数: 0

Measuring quantum relative entropy with finite-size effect 用有限尺寸效应测量量子相对熵

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-05-05 DOI: 10.22331/q-2025-05-05-1725

Masahito Hayashi

引用次数: 0

Hierarchical memories: Simulating quantum LDPC codes with local gates 分层存储器：用局部门模拟量子LDPC码

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-05-05 DOI: 10.22331/q-2025-05-05-1728

Christopher A. Pattison, Anirudh Krishna, John Preskill

引用次数: 0

Partitioned Quantum Subspace Expansion 分块量子子空间展开

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-05-05 DOI: 10.22331/q-2025-05-05-1726

Tom O'Leary, Lewis W. Anderson, Dieter Jaksch, Martin Kiffner

引用次数: 0

Pauli path simulations of noisy quantum circuits beyond average case 超越平均情况的噪声量子电路泡利路径模拟

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2025-05-05 DOI: 10.22331/q-2025-05-05-1730

Guillermo González-García, J. Ignacio Cirac, Rahul Trivedi

{"title":"Pauli path simulations of noisy quantum circuits beyond average case","authors":"Guillermo González-García, J. Ignacio Cirac, Rahul Trivedi","doi":"10.22331/q-2025-05-05-1730","DOIUrl":"https://doi.org/10.22331/q-2025-05-05-1730","url":null,"abstract":"For random quantum circuits on $n$ qubits of depth $Theta(log n)$ with depolarizing noise, the task of sampling from the output state can be efficiently performed classically using a Pauli path method [1] . This paper aims to study the performance of this method beyond random circuits. We first consider the classical simulation of local observables in circuits composed of Clifford and T gates $unicode{x2013}$ going beyond the average case analysis, we derive sufficient conditions for simulatability in terms of the noise rate and the fraction of gates that are T gates, and show that if noise is introduced at a faster rate than T gates, the simulation becomes classically easy. As an application of this result, we study 2D QAOA circuits that attempt to find low-energy states of classical Ising models on general graphs. There, our results shows that for hard instances of the problem, which correspond to Ising model's graph being geometrically non-local, a QAOA algorithm mapped to a geometrically local circuit architecture using SWAP gates does not have any asymptotic advantage over classical algorithms if depolarized at a constant rate. Finally, we illustrate instances where the Pauli path method fails to give the correct result, and also initiate a study of the trade-off between fragility to noise and classical complexity of simulating a given quantum circuit.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"24 1","pages":"1730"},"PeriodicalIF":6.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143910415","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