Work and entropy production in generalised Gibbs ensembles
Work and entropy production in generalised Gibbs ensembles
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DOI：
10.1088/1367-2630/aa4fa6
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发表时间：
2016-12-23
影响因子：
3.3
通讯作者：
Eisert, Jens
中科院分区：
文献类型：
--
作者：
Perarnau-Llobet, Marti;Riera, Arnau;Eisert, Jens
近年来，人们对量子体系中的热力学概念的研究又有了极大的兴趣。这既适用于研究概念的工作提取热机在量子制度，以及问题的平衡和热化的相互作用的量子多体系统。在这项工作中，我们汇集了这两条线的研究，通过研究工作提取在一个封闭的系统，经历了一系列的淬火和平衡步骤伴随着自由的演变。通过这种方式，我们从量子多体系统动力学的研究中引入了一个重要的见解：对于相关的可观测量和大多数情况下，封闭系统的演化有望通过合适的平衡态得到很好的描述。我们将考虑三种平衡，即（i）时间平均状态，（ii）吉布斯系综和（iii）广义吉布斯系综，反映了可积模型中的运动常数。对于每一个有效的描述，我们调查的概念熵产生，最小工作原理的有效性和最佳工作提取协议的属性。虽然我们保持一般的讨论，大部分的空间是专门讨论的范式非相互作用的费米量子多体系统，我们确定显着的差异方面的作用的最小功原理。我们的工作不仅对冷原子实验有影响，而且可以被视为暗示了量子热力学的一种思维方式，即外部热浴的作用由系统本身发挥，其内部自由度使粗粒度的可观测量达到平衡。
Recent years have seen an enormously revived interest in the study of thermodynamic notions in the quantum regime. This applies both to the study of notions of work extraction in thermal machines in the quantum regime, as well as to questions of equilibration and thermalisation of interacting quantum many-body systems as such. In this work we bring together these two lines of research by studying work extraction in a closed system that undergoes a sequence of quenches and equilibration steps concomitant with free evolutions. In this way, we incorporate an important insight from the study of the dynamics of quantum many body systems: the evolution of closed systems is expected to be well described, for relevant observables and most times, by a suitable equilibrium state. We will consider three kinds of equilibration, namely to (i) the time averaged state, (ii) the Gibbs ensemble and (iii) the generalised Gibbs ensemble, reflecting further constants of motion in integrable models. For each effective description, we investigate notions of entropy production, the validity of the minimal work principle and properties of optimal work extraction protocols. While we keep the discussion general, much room is dedicated to the discussion of paradigmatic non-interacting fermionic quantum many-body systems, for which we identify significant differences with respect to the role of the minimal work principle. Our work not only has implications for experiments with cold atoms, but also can be viewed as suggesting a mindset for quantum thermodynamics where the role of the external heat baths is instead played by the system itself, with its internal degrees of freedom bringing coarse-grained observables to equilibrium.