Assessing the Nonequilibrium Thermodynamics in a Quenched Quantum Many-Body System via Single Projective Measurements
Assessing the Nonequilibrium Thermodynamics in a Quenched Quantum Many-Body System via Single Projective Measurements
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DOI：
10.1103/physrevx.4.031029
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发表时间：
2014-08-19
影响因子：
12.5
通讯作者：
De Chiara, G.
中科院分区：
文献类型：
--
作者：
Fusco, L.;Pigeon, S.;De Chiara, G.
我们分析了量子多体系统在平衡状态下所做的功的统计性质。我们表明，突然淬火和交换与初始哈密顿量的初始状态，它是可能的，以恢复整个非平衡热力学通过单投影测量的可观。我们强调，在一个物理上明确的方式，定性的影响，统计的工作来自考虑由运营商描述的过程中，无论是通勤或不与一个给定的系统的未扰动哈密顿。我们考虑一个量子多体系统，并推导出一个表达式，使我们能够给出一个物理解释，热初始状态，所有的累积量的工作的情况下，淬火运营商与未扰动的哈密顿量交换。在通勤的情况下，我们需要测量的可观测量具有直观的物理意义。相反，在noncommuting的情况下，我们表明，虽然它是可以完全在单测量框架内运作，而不管淬火的大小，一些困难是面临着在提供一个明确的物理解释的累积量。这种情况使得对系统物理的研究变得不平凡，并突出了从完全量子微观描述中出现热力学的非直观现象学。我们说明了我们的想法的例子中的伊辛模型在横向领域显示有趣的行为的高阶统计矩的工作分布的一个通用的热状态，并将它们连接到模型本身的临界性质。
We analyze the nature of the statistics of the work done on or by a quantum many-body system brought out of equilibrium. We show that, for the sudden quench and for an initial state that commutes with the initial Hamiltonian, it is possible to retrieve the whole nonequilibrium thermodynamics via single projective measurements of observables. We highlight, in a physically clear way, the qualitative implications for the statistics of work coming from considering processes described by operators that either commute or do not commute with the unperturbed Hamiltonian of a given system. We consider a quantum many-body system and derive an expression that allows us to give a physical interpretation, for a thermal initial state, to all of the cumulants of the work in the case of quenched operators commuting with the unperturbed Hamiltonian. In the commuting case, the observables that we need to measure have an intuitive physical meaning. Conversely, in the noncommuting case, we show that, although it is possible to operate fully within the single-measurement framework irrespectively of the size of the quench, some difficulties are faced in providing a clear-cut physical interpretation to the cumulants. This circumstance makes the study of the physics of the system nontrivial and highlights the nonintuitive phenomenology of the emergence of thermodynamics from the fully quantum microscopic description. We illustrate our ideas with the example of the Ising model in a transverse field showing the interesting behavior of the high-order statistical moments of the work distribution for a generic thermal state and linking them to the critical nature of the model itself.