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arXiv 2109.10620quant-phcond-mat.stat-mech
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量子碰撞恒温器

Quantum collisional thermostats

Jorge Tabanera, Ines Luque, Samuel L. Jacob, Massimiliano Esposito, Felipe Barra, Juan M. R. Parrondo

摘要:

碰撞库正在成为建模开放量子系统的主要工具。在其最简单的实施方式中,外部代理在给定时间内开启系统与来自储器的样本之间的相互作用。一般来说,在这种操作中,外部介质对系统做功,防止储层处于平衡状态时的热化。人们可以通过考虑一个自治的全局设置来恢复热化,其中与系统碰撞的储层粒子具有动力学自由度。缺点是,相应的散射问题是相当复杂的。在这里,我们提出了一个正式的解决方案,在一维和平坦的相互作用潜力的问题。该解决方案是基于传输矩阵形式主义,并允许一个探索所产生的散射映射的对称性。这些对称性之一是微观可逆性,这是热化的条件。然后,我们引入两个近似的散射映射,保持这些对称性,因此,热化系统。这些相对简单的近似解构成了量子恒温器的模型,是研究与热浴接触的量子系统的有用工具。我们说明了他们的准确性在一个具体的例子中,表明这两个很好的近似的精确散射问题,即使在远离平衡的情况下。此外,其中一个模型包括删除某些cohesive加上一个非常具体的随机化的相互作用时间。这两个特征允许人们将由于打开和关闭相互作用而引起的能量传递识别为热。我们的研究结果提示了一个基本问题,即如何从系统与其周围环境之间能量交换的统计特性中区分热和功。

英文摘要:

Collisional reservoirs are becoming a major tool for modelling open quantum systems. In their simplest implementation, an external agent switches on, for a given time, the interaction between the system and a specimen from the reservoir. Generically, in this operation the external agent performs work onto the system, preventing thermalization when the reservoir is at equilibrium. One can recover thermalization by considering an autonomous global setup where the reservoir particles colliding with the system possess a kinetic degree of freedom. The drawback is that the corresponding scattering problem is rather involved. Here, we present a formal solution of the problem in one dimension and for flat interaction potentials. The solution is based on the transfer matrix formalism and allows one to explore the symmetries of the resulting scattering map. One of these symmetries is micro-reversibility, which is a condition for thermalization. We then introduce two approximations of the scattering map that preserve these symmetries and, consequently, thermalize the system. These relatively simple approximate solutions constitute models of quantum thermostats and are useful tools to study quantum systems in contact with thermal baths. We illustrate their accuracy in a specific example, showing that both are good approximations of the exact scattering problem even in situations far from equilibrium. Moreover, one of the models consists of the removal of certain coherences plus a very specific randomization of the interaction time. These two features allow one to identify as heat the energy transfer due to switching on and off the interaction. Our results prompt the fundamental question of how to distinguish between heat and work from the statistical properties of the exchange of energy between a system and its surroundings.

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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