Quantum最新文献 - Book学术

Port-Based State Preparation and Applications 港口国准备和应用

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-12-18 DOI: 10.22331/q-2024-12-18-1573

Garazi Muguruza, Florian Speelman

引用次数: 0

Efficient tensor networks for control-enhanced quantum metrology

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-12-18 DOI: 10.22331/q-2024-12-18-1571

Qiushi Liu, Yuxiang Yang

引用次数: 0

Heralded Optical Entanglement Generation via the Graph Picture of Linear Quantum Networks

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-12-18 DOI: 10.22331/q-2024-12-18-1572

Seungbeom Chin, Marcin Karczewski, Yong-Su Kim

{"title":"Heralded Optical Entanglement Generation via the Graph Picture of Linear Quantum Networks","authors":"Seungbeom Chin, Marcin Karczewski, Yong-Su Kim","doi":"10.22331/q-2024-12-18-1572","DOIUrl":"https://doi.org/10.22331/q-2024-12-18-1572","url":null,"abstract":"Non-destructive heralded entanglement with photons is a valuable resource for quantum information processing. However, they generally entail ancillary particles and modes that amplify the circuit intricacy. To address this challenge, a recent work [16] introduced a graph approach for creating multipartite entanglements with boson subtractions. Nonetheless, it remains an essential intermediate step toward practical heralded schemes: the proposition of heralded subtraction operators in bosonic linear quantum networks. This research establishes comprehensive translation rules from subtraction operators to linear optical operators, which provides a seamless path to design heralded schemes with single photons. Our method begets enhanced or previously unreported schemes for the $N$-partite GHZ state with $2N$ photons, $N$-partite W state with $2N+1$ photons and superposition of $N=3$ GHZ and W states with 9 photons. Our streamlined approach can straightforwardly design heralded schemes for multipartite entangled states by assembling the operators according to the guidence of sculpting bigraphs, hence significantly simplifies the quantum circuit design process.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"13 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841418","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

Fiat-Shamir for Proofs Lacks a Proof Even in the Presence of Shared Entanglement 即使存在共享纠缠，证明的菲亚特-沙米尔也缺乏证明

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-12-17 DOI: 10.22331/q-2024-12-17-1568

Frédéric Dupuis, Philippe Lamontagne, Louis Salvail

{"title":"Fiat-Shamir for Proofs Lacks a Proof Even in the Presence of Shared Entanglement","authors":"Frédéric Dupuis, Philippe Lamontagne, Louis Salvail","doi":"10.22331/q-2024-12-17-1568","DOIUrl":"https://doi.org/10.22331/q-2024-12-17-1568","url":null,"abstract":"We explore the cryptographic power of arbitrary shared physical resources. The most general such resource is access to a fresh entangled quantum state at the outset of each protocol execution. We call this the $textit{Common Reference Quantum State (CRQS)}$ model, in analogy to the well-known $textit{Common Reference String (CRS)}$. The CRQS model is a natural generalization of the CRS model but appears to be more powerful: in the two-party setting, a CRQS can sometimes exhibit properties associated with a Random Oracle queried once by measuring a maximally entangled state in one of many mutually unbiased bases. We formalize this notion as a $textit{Weak One-Time Random Oracle (WOTRO)}$, where we only ask of the $m$-bit output to have some randomness when conditioned on the $n$-bit input.<br/> We show that when $n-minomega(lg n)$, any protocol for WOTRO in the CRQS model can be attacked by an (inefficient) adversary. Moreover, our adversary is efficiently simulatable, which rules out the possibility of proving the computational security of a scheme by a fully black-box reduction to a cryptographic game assumption. On the other hand, we introduce a non-game quantum assumption for hash functions that implies WOTRO in the CRQS model (where the CRQS consists only of EPR pairs). We first build a statistically secure WOTRO protocol where $m=n$, then hash the output.<br/> The impossibility of WOTRO has the following consequences. First, we show the fully-black-box impossibility of a $quantum$ Fiat-Shamir transform, extending the impossibility result of Bitansky et al. (TCC 2013) to the CRQS model. Second, we show a fully-black-box impossibility result for a strenghtened version of quantum lightning (Zhandry, Eurocrypt 2019) where quantum bolts have an additional parameter that cannot be changed without generating new bolts. Our results also apply to $2$-message protocols in the plain model.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"9 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142831986","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 time-dependent Hamiltonians via commutator-free quasi-Magnus operators 通过无换元准马格努斯算子对依赖时间的哈密顿量子模拟

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-12-17 DOI: 10.22331/q-2024-12-17-1567

Pablo Antonio Moreno Casares, Modjtaba Shokrian Zini, Juan Miguel Arrazola

引用次数: 0

No-Regret Learning and Equilibrium Computation in Quantum Games

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-12-17 DOI: 10.22331/q-2024-12-17-1569

Wayne Lin, Georgios Piliouras, Ryann Sim, Antonios Varvitsiotis

{"title":"No-Regret Learning and Equilibrium Computation in Quantum Games","authors":"Wayne Lin, Georgios Piliouras, Ryann Sim, Antonios Varvitsiotis","doi":"10.22331/q-2024-12-17-1569","DOIUrl":"https://doi.org/10.22331/q-2024-12-17-1569","url":null,"abstract":"As quantum processors advance, the emergence of large-scale decentralized systems involving interacting quantum-enabled agents is on the horizon. Recent research efforts have explored quantum versions of Nash and correlated equilibria as solution concepts of strategic quantum interactions, but these approaches did not directly connect to decentralized adaptive setups where agents possess limited information. This paper delves into the dynamics of quantum-enabled agents within decentralized systems that employ no-regret algorithms to update their behaviors over time. Specifically, we investigate two-player quantum zero-sum games and polymatrix quantum zero-sum games, showing that no-regret algorithms converge to separable quantum Nash equilibria in time-average. In the case of general multi-player quantum games, our work leads to a novel solution concept, that of the separable quantum coarse correlated equilibria (QCCE), as the convergent outcome of the time-averaged behavior no-regret algorithms, offering a natural solution concept for decentralized quantum systems. Finally, we show that computing QCCEs can be formulated as a semidefinite program and establish the existence of entangled (i.e., non-separable) QCCEs, which are unlearnable via the current paradigm of no-regret learning.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"47 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142831990","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 Kernel Machine Learning With Continuous Variables 使用连续变量的量子核机器学习

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-12-17 DOI: 10.22331/q-2024-12-17-1570

Laura J. Henderson, Rishi Goel, Sally Shrapnel

{"title":"Quantum Kernel Machine Learning With Continuous Variables","authors":"Laura J. Henderson, Rishi Goel, Sally Shrapnel","doi":"10.22331/q-2024-12-17-1570","DOIUrl":"https://doi.org/10.22331/q-2024-12-17-1570","url":null,"abstract":"The popular qubit framework has dominated recent work on quantum kernel machine learning, with results characterising expressivity, learnability and generalisation. As yet, there is no comparative framework to understand these concepts for continuous variable (CV) quantum computing platforms. In this paper we represent CV quantum kernels as closed form functions and use this representation to provide several important theoretical insights. We derive a general closed form solution for all CV quantum kernels and show every such kernel can be expressed as the product of a Gaussian and an algebraic function of the parameters of the feature map. Furthermore, in the multi-mode case, we present quantification of a quantum-classical separation for all quantum kernels via a hierarchical notion of the “stellar rank\" of the quantum kernel feature map. We then prove kernels defined by feature maps of infinite stellar rank, such as GKP-state encodings, can be approximated arbitrarily well by kernels defined by feature maps of finite stellar rank. Finally, we simulate learning with a single-mode displaced Fock state encoding and show that (i) accuracy on our specific task (an annular data set) increases with stellar rank, (ii) for underfit models, accuracy can be improved by increasing a bandwidth hyperparameter, and (iii) for noisy data that is overfit, decreasing the bandwidth will improve generalisation but does so at the cost of effective stellar rank.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"3 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142831988","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

Negative Wigner function by decaying interaction from equilibrium 通过从平衡状态开始的相互作用衰减产生负维格纳函数

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-12-17 DOI: 10.22331/q-2024-12-17-1566

Michal Kolář, Radim Filip

引用次数: 0

A healthier semi-classical dynamics 更健康的半经典动力学

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-12-16 DOI: 10.22331/q-2024-12-16-1565

Isaac Layton, Jonathan Oppenheim, Zachary Weller-Davies

{"title":"A healthier semi-classical dynamics","authors":"Isaac Layton, Jonathan Oppenheim, Zachary Weller-Davies","doi":"10.22331/q-2024-12-16-1565","DOIUrl":"https://doi.org/10.22331/q-2024-12-16-1565","url":null,"abstract":"We study the back-reaction of quantum systems onto classical ones. Taking the starting point that semi-classical physics should be described at all times by a point in classical phase space and a quantum state in Hilbert space, we consider an unravelling approach, describing the system in terms of a classical-quantum trajectory. We derive the general form of the dynamics under the assumptions that the classical trajectories are continuous and the evolution is autonomous, and the requirement that the dynamics is linear and completely positive in the combined classical-quantum state. This requirement is necessary in order to consistently describe probabilities, and forces the dynamics to be stochastic when the back-reaction is non-zero. The resulting equations of motion are natural generalisations of the standard semi-classical equations of motion, but since the resulting dynamics is linear in the combined classical-quantum state, it does not lead to the pathologies which usually follow from evolution laws based on expectation values. In particular, the evolution laws we present account for correlations between the classical and quantum system, which resolves issues associated with other semi-classical approaches. In addition, despite a breakdown of predictability in the classical degrees of freedom, the quantum state evolves deterministically conditioned on the classical trajectory, provided a trade-off between decoherence and diffusion is saturated. As a result, the quantum state remains pure when conditioned on the classical trajectory. To illustrate these points, we numerically simulate a number of semi-classical toy models, including one of vacuum fluctuations as a source driving the expansion of the universe. Finally, we discuss the application of these results to semi-classical gravity, and the black-hole information problem.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"38 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142831984","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 Circuits for partial differential equations via Schrödingerisation

IF 6.4 2区物理与天体物理

Quantum Pub Date : 2024-12-12 DOI: 10.22331/q-2024-12-12-1563

Junpeng Hu, Shi Jin, Nana Liu, Lei Zhang

引用次数: 0