论文标题

WEHRL熵的生产率跨动态量子相变

Wehrl entropy production rate across a dynamical quantum phase transition

论文作者

Goes, B. O., Landi, G. T., Solano, E., Sanz, M., Céleri, L. C.

论文摘要

多体量子系统的淬火动力学可能在洛奇米特回波中表现出非分析性,这是一种被称为动力学相变(DPT)的现象。尽管对这种现象背后的基本机制进行了大量研究,但仍然存在一些开放问题。在此激励的情况下,我们从量子相空间和熵产生的角度进行了详细研究DPT,这是热力学中的关键概念。我们专注于Lipkin-Meshkov-Glick型号,并使用旋转相干状态构建相应的Husimi- $ Q $ Quasi-Quasi-Obobyability分布。 $ q $ - 功能的熵,称为WEHRL熵,提供了系统的粗粒动力学的度量,因此即使是封闭的系统,也会在非琐事上演变。我们表明,临界淬灭会导致WEHRL熵的准单调生长,并结合小振荡。前者反映了这些过渡的信息争夺特征,并用作熵产生的量度。另一方面,较小的振荡意味着负熵的生产率,因此,向洛斯米德(Loschmidt)回波的复发发出了信号。最后,我们还基于修改的荷斯坦 - 普罗里马科夫近似值研究模型的豪斯化。这使我们能够确定低能源部门对DPT出现的相对贡献。本文介绍的结果不仅是从动态量子相变的角度来看的,而且与量子热力学领域有关,因为它们指出WEHRL熵可以用作可行的熵产生量度。

The quench dynamics of many-body quantum systems may exhibit non-analyticities in the Loschmidt echo, a phenomenon known as dynamical phase transition (DPT). Despite considerable research into the underlying mechanisms behind this phenomenon, several open questions still remain. Motivated by this, we put forth a detailed study of DPTs from the perspective of quantum phase space and entropy production, a key concept in thermodynamics. We focus on the Lipkin-Meshkov-Glick model and use spin coherent states to construct the corresponding Husimi-$Q$ quasi-probability distribution. The entropy of the $Q$-function, known as Wehrl entropy, provides a measure of the coarse-grained dynamics of the system and, therefore, evolves non-trivially even for closed systems. We show that critical quenches lead to a quasi-monotonic growth of the Wehrl entropy in time, combined with small oscillations. The former reflects the information scrambling characteristic of these transitions and serves as a measure of entropy production. On the other hand, the small oscillations imply negative entropy production rates and, therefore, signal the recurrences of the Loschmidt echo. Finally, we also study a Gaussification of the model based on a modified Holstein-Primakoff approximation. This allows us to identify the relative contribution of the low energy sector to the emergence of DPTs. The results presented in this article are relevant not only from the dynamical quantum phase transition perspective, but also for the field of quantum thermodynamics, since they point out that the Wehrl entropy can be used as a viable measure of entropy production.

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