物理学进展 ›› 2018, Vol. 38 ›› Issue (1): 1-63.

• •    下一篇

马尔科夫量子主方程的热和功: 概念, 涨落定理和计算

柳飞   

  • 出版日期:2020-10-12 发布日期:2020-10-12

Heat and work in Markovian quantum master equations: concepts, uctuation theorems, and computations

Liu Fei   

  • Online:2020-10-12 Published:2020-10-12

摘要: 马尔科夫量子主方程的确立将近半个世纪,它们经常被用于不可逆热力学的研究。然而,在 过去相当长的一段时间里,这些研究几乎只关注了系综平均的结果,量子系统的随机热力学一直未 受到重视。由于过去二十年里各种经典和量子涨落定理的发现,这种状况才有了明显地改变。在本 文中,我们采用两种不同的策略系统总结了当前对马尔科夫量子主方程的随机的热和功的理解。策 略之一是把量子系统和其周围的热库当成是一个封闭的量子系统,在含时总哈密顿量的控制下,这 个系统发生幺正演化,对该复合系统做两次能量投影测量得到的能量本征值之差被定义为热和功。 另一种策略是首先把量子主方程分解成随机的量子跳跃轨迹,然后在轨迹上定义随机的热和功。我 们以尽可能详尽的方式介绍这些重要的物理概念、数学技术以及不同描述层次的涨落定理。我们也 用模型具体地说明这些结论。

关键词: 随机量子热力学, 两次能量测量, 量子跳跃轨迹, 特征函数

Abstract: Markovian quantum master equations (MQMEs) were established nearly half a century ago. They have often been used in the study of irreversible thermodynamics. However, the previous results were mainly concerned about ensemble averages; the stochastic thermodynamics of these systems went unnoticed for a very long time. This situation remained unchanged until a variety of fluctuation theorems in classical and quantum regimes were found in the past two decades. In this paper, we systematically summarize the current understanding on the stochastic heat and work in MQMEs using two distinct strategies. One strategy is to treat the system and its surrounding heat bath as a closed quantum system, to suppose that the evolution of the composite system is unitary under a time-dependent total Hamiltonian and to define the heat and work as the changes in energy by applying two energy measurements scheme to the composite system. The other strategy is to unravel these MQMEs into random quantum jump trajectories (QJTs) and to define the stochastic heat and work along the individual trajectories. Many physical important concepts, mathematical techniques, and fluctuation theorems at different descriptive levels are given in as detailed a manner as possible. We also use concrete models to illustrate these results.

Key words: Stochastic quantum thermodynamics, Two-energy-measurement, Quantum jump trajectory, Characteristic functions