Quantum最新文献 - Book学术

Regular language quantum states 规则语言量子态

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2026-04-29 DOI: 10.22331/q-2026-04-29-2089

Marta Florido-Llinàs, Álvaro M. Alhambra, David Pérez-García, J. Ignacio Cirac

引用次数: 0

Disentangling strategies and entanglement transitions in unitary circuit games with matchgates 有匹配门的幺正电路博弈中的解纠缠策略和纠缠转换

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2026-04-28 DOI: 10.22331/q-2026-04-28-2087

Raúl Morral-Yepes, Marc Langer, Adam Gammon-Smith, Barbara Kraus, Frank Pollmann

{"title":"Disentangling strategies and entanglement transitions in unitary circuit games with matchgates","authors":"Raúl Morral-Yepes, Marc Langer, Adam Gammon-Smith, Barbara Kraus, Frank Pollmann","doi":"10.22331/q-2026-04-28-2087","DOIUrl":"https://doi.org/10.22331/q-2026-04-28-2087","url":null,"abstract":"In unitary circuit games, two competing parties, an \"entangler\" and a \"disentangler\", can induce an entanglement phase transition in a quantum many-body system. The transition occurs at a certain rate at which the disentangler acts. We analyze such games within the context of matchgate dynamics, which equivalently corresponds to evolutions of non-interacting fermions. We first investigate general entanglement properties of fermionic Gaussian states (FGS). We introduce a representation of FGS using a minimal matchgate circuit capable of preparing the state and derive an algorithm based on a generalized Yang-Baxter relation for updating this representation as unitary operations are applied. This representation enables us to define a natural disentangling procedure that reduces the number of gates in the circuit, thereby decreasing the entanglement contained in the system. We then explore different strategies to disentangle the systems and study the unitary circuit game in two different scenarios: with braiding gates, i.e., the intersection of Clifford gates and matchgates, and with generic matchgates. For each model, we observe qualitatively different entanglement transitions, which we characterize both numerically and analytically.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"5 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147755084","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

“Nonlocality-of-a-single-photon” based Quantum Key Distribution and Random Number Generation schemes and their device-independent security analysis 基于“单光子非局域性”的量子密钥分发和随机数生成方案及其与设备无关的安全性分析

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2026-04-28 DOI: 10.22331/q-2026-04-28-2084

Konrad Schlichtholz, Bianka Woloncewicz, Tamoghna Das, Marcin Markiewicz, Marek Żukowski

{"title":"“Nonlocality-of-a-single-photon” based Quantum Key Distribution and Random Number Generation schemes and their device-independent security analysis","authors":"Konrad Schlichtholz, Bianka Woloncewicz, Tamoghna Das, Marcin Markiewicz, Marek Żukowski","doi":"10.22331/q-2026-04-28-2084","DOIUrl":"https://doi.org/10.22331/q-2026-04-28-2084","url":null,"abstract":"The question of “non-locality of a single photon'', which started with a paper by Tan, Walls and Collett (TWC, 1991) stirred a thirty years long debate. This hampered attempts to use the TWC interferometric scheme in quantum cryptography. The scheme involves a single photon 50-50 beam-split into two modes propagating to two spatially separated observation stations at which weak homodyne measurements are made. The physics and non-classicality of such an arrangement has been understood only recently, and points out that an unquestionable Bell non-classicality, as was suggested by Hardy (1994), can be observed when the local measurement settings differ by the weak local oscillator being on or off, and additionally the homodyning for the on case is not balanced. Based on that, we present a single-photon based device-independent quantum key distribution scheme secure even against no-signaling eavesdropping. In our protocol the random bits of the cryptographic key are obtained by measurements on the single photon, that is for off settings at both Alice and Bob sides, while the security is positively tested if for eavesdropping testing runs one observes a violation of a specific Bell inequality involving the on and off weak homodyne measurements as alternative local settings. The security analysis presented here is based on a decomposition of the correlations into extreme points of a no-signaling polytope, which allows for identification of the optimal strategy for any eavesdropping constrained only by the no-signaling principle. For this strategy, the key rate is calculated, which is then connected with the violation of a specific Clauser-Horne inequality. We also adapt this analysis to propose a self-testing quantum random number generator based on the old idea that employs the randomness of reflection and transmission events of a quantum light impinged on a 50-50 beamsplitter.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"300 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147755082","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 correlations in the steady state of light-emitter ensembles from perturbation theory 从摄动理论看光-发射器系综稳态中的量子相关

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2026-04-28 DOI: 10.22331/q-2026-04-28-2085

Dolf Huybrechts, Tommaso Roscilde

{"title":"Quantum correlations in the steady state of light-emitter ensembles from perturbation theory","authors":"Dolf Huybrechts, Tommaso Roscilde","doi":"10.22331/q-2026-04-28-2085","DOIUrl":"https://doi.org/10.22331/q-2026-04-28-2085","url":null,"abstract":"The coupling of a quantum system to an environment leads generally to decoherence, and it is detrimental to quantum correlations within the system itself. Yet some forms of quantum correlations can be robust to the presence of an environment – or may even be stabilized by it. Predicting (let alone understanding) them remains arduous, given that the steady state of an open quantum system can be very different from an equilibrium thermodynamic state; and its reconstruction requires generically the numerical solution of the Lindblad equation, which is extremely costly for numerics. Here we focus on the highly relevant situation of ensembles of light emitters undergoing spontaneous decay; and we show that, whenever their Hamiltonian is perturbed away from a U(1) symmetric form, steady-state quantum correlations can be reconstructed via pure-state perturbation theory. Our main result is that in systems of light emitters subject to single-emitter or two-emitter driving, the steady state perturbed away from the U(1) limit generically exhibits spin squeezing; and it has minimal uncertainty for the collective-spin components, revealing that squeezing represents the optimal resource for entanglement-assisted metrology using this state.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"47 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147755083","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

RandomMeas.jl: A Julia Package for Randomized Measurements in Quantum Devices RandomMeas。[j]：量子器件随机测量的Julia包

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2026-04-28 DOI: 10.22331/q-2026-04-28-2086

Andreas Elben, Benoit Vermersch

引用次数: 0

Monogamy of Entanglement Bounds and Improved Approximation Algorithms for Qudit Hamiltonians 量子哈密顿算子的纠缠界一夫一妻制及改进逼近算法

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2026-04-28 DOI: 10.22331/q-2026-04-28-2088

Zackary Jorquera, Alexandra Kolla, Steven Kordonowy, Juspreet Singh Sandhu, Stuart Wayland

引用次数: 0

Wire Codes 线码

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2026-04-24 DOI: 10.22331/q-2026-04-24-2083

Nouédyn Baspin, Dominic Williamson

{"title":"Wire Codes","authors":"Nouédyn Baspin, Dominic Williamson","doi":"10.22331/q-2026-04-24-2083","DOIUrl":"https://doi.org/10.22331/q-2026-04-24-2083","url":null,"abstract":"Quantum information is fragile and must be protected by a quantum error-correcting code for large-scale practical applications. Recently, highly efficient quantum codes have been discovered which require a high degree of spatial connectivity. This raises the question of how to realize these codes with minimal overhead under physical hardware connectivity constraints. Here, we introduce a general recipe to transform any quantum stabilizer code into a subsystem code that has local interactions, with weight and degree three, on a given graph. We call the subsystem codes produced by our recipe wire codes, and their code parameters depend on the input code and the given graph. Wire codes can be adapted to have a local implementation on any graph that supports a low-density embedding of the input Tanner graph, with an overhead that depends on the embedding. In particular, applying our results to a stabilizer code and a subdivision of its own Tanner graph, yields a quantum weight reduction procedure with a multiplicative qubit overhead and distance reduction that are linear in the input check degree and weight, respectively. Applying our results to hypercubic lattices leads to a construction of local subsystem codes with optimal scaling code parameters in any fixed spatial dimension. Similarly, applying our results to families of expanding graphs leads to local codes on these graphs with code parameters that depend on the degree of expansion. Our results constitute a general method to construct low-overhead subsystem codes on general graphs, which can be applied to adapt highly efficient quantum error correction procedures to hardware with restricted connectivity.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"423 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147736570","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

Holonomic quantum computation: a scalable adiabatic architecture 完整量子计算：可扩展绝热体系结构

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2026-04-23 DOI: 10.22331/q-2026-04-23-2080

Clara Wassner, Tommaso Guaita, Jens Eisert, Jose Carrasco

引用次数: 0

Fibonacci Waveguide Quantum Electrodynamics 斐波那契波导量子电动力学

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2026-04-23 DOI: 10.22331/q-2026-04-23-2081

Florian Bönsel, Flore K. Kunst, Federico Roccati

{"title":"Fibonacci Waveguide Quantum Electrodynamics","authors":"Florian Bönsel, Flore K. Kunst, Federico Roccati","doi":"10.22331/q-2026-04-23-2081","DOIUrl":"https://doi.org/10.22331/q-2026-04-23-2081","url":null,"abstract":"Waveguide quantum electrodynamics (QED) provides a powerful framework for engineering quantum interactions, traditionally relying on periodic photonic arrays with continuous energy bands. Here, we investigate waveguide QED in a fundamentally different environment: A one-dimensional photonic array whose hopping strengths are structured aperiodically according to the deterministic Fibonacci-Lucas substitution rule. These \"Fibonacci waveguides\" lack translational invariance and are characterized by a singular continuous energy spectrum and critical eigenstates, representing a deterministic intermediate between ordered and disordered systems. We demonstrate how to achieve decoherence-free, coherent interactions in this unique setting. We analyze two paradigmatic cases: (i) Giant emitters resonantly coupled to the simplest aperiodic version of a standard waveguide. For these, we show that atom photon bound states form only for specific coupling configurations dictated by the aperiodic sequence, leading to an effective atomic Hamiltonian, which itself inherits the Fibonacci structure; and (ii) emitters locally and off-resonantly coupled to the aperiodic version of the Su-Schrieffer-Heeger waveguide. In this case the mediating bound states feature aperiodically modulated profiles, resulting in an effective Hamiltonian with multifractal properties. Our work establishes Fibonacci waveguides as a versatile platform, which is experimentally feasible, demonstrating that the deterministic complexity of aperiodic structures can be directly engineered into the interactions between quantum emitters.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"67 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147736569","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

Variational subspace methods and application to improving variational Monte Carlo dynamics 变分子空间方法及其在改进变分蒙特卡罗动力学中的应用

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2026-04-23 DOI: 10.22331/q-2026-04-23-2082

Adrien Kahn, Luca Gravina, Filippo Vicentini

引用次数: 0