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arXiv 2403.17138quant-phcond-mat.quant-gascond-mat.stat-mech
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量子热力学和多体系统中的准概率

Quasiprobabilities in quantum thermodynamics and many-body systems

Stefano Gherardini, Gabriele De Chiara

AI总结:

本教程介绍准概率的定义、性质及实验获取方法,并展示其在量子热力学中解释功、热异常及多体系统中信息扰乱等应用,核心贡献是系统阐述Kirkwood-Dirac准概率并促进理解。

摘要:

在本教程中,我们介绍了可以描述在两个或多个时间点评估的测量结果统计的一些主要准概率的定义、解释和性质。此类统计包含了测量可观测量的不相容性和被测量子系统的状态。我们特别关注Kirkwood-Dirac准概率及相关分布。我们还讨论了实验上获取准概率分布的技术,从弱两点测量方案,到类似Ramsey的干涉测量方案以及由外部探测器辅助的程序。我们展示了准概率在量子热力学中的应用,用于描述功和热的量子统计,并解释给定热力学变换所涉及的能量交换中的异常。一方面,在功协议中,我们展示了由于不同时间的哈密顿量不相容性,吸收的能量如何转化为可提取的功,反之亦然。另一方面,在两个初始温度不同的量子系统之间的交换过程中,我们解释了其初始状态中的量子相关性如何可能诱导冷到热的能量交换,这在任何一对平衡非驱动系统之间都是不自然的。我们通过给出准概率应用于多体系统的简单示例来结束本教程:量子信息的扰乱、对局部扰动的敏感性,以及可映射到自由费米子系统的模型(例如具有横向场的Ising模型)的淬火动力学中的量子功统计。我们精心呈现了基本概念的推导以及简单的例子,旨在增强理解并促进学习。

英文摘要:

In this tutorial, we present the definition, interpretation and properties of some of the main quasiprobabilities that can describe the statistics of measurement outcomes evaluated at two or more times. Such statistics incorporate the incompatibility of the measurement observables and the state of the measured quantum system. We particularly focus on Kirkwood-Dirac quasiprobabilities and related distributions. We also discuss techniques to experimentally access a quasiprobability distribution, ranging from the weak two-point measurement scheme, to a Ramsey-like interferometric scheme and procedures assisted by an external detector. We illustrate the use of quasiprobabilities in quantum thermodynamics to describe the quantum statistics of work and heat, and to explain anomalies in the energy exchanges entailed by a given thermodynamic transformation. On the one hand, in work protocols, we show how absorbed energy can be converted to extractable work and vice versa due to Hamiltonian incompatibility at distinct times. On the other hand, in exchange processes between two quantum systems initially at different temperatures, we explain how quantum correlations in their initial state may induce cold-to-hot energy exchanges, which are unnatural between any pair of equilibrium nondriven systems. We conclude the tutorial by giving simple examples where quasiprobabilities are applied to many-body systems: scrambling of quantum information, sensitivity to local perturbations, and quantum work statistics in the quenched dynamics of models that can be mapped onto systems of free fermions, for instance the Ising model with a transverse field. We meticulously present derivations of essential concepts alongside straightforward examples, aiming to enhance comprehension and facilitate learning.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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