Thermodynamic description of non-Markovian information flux of nonequilibrium open quantum systems

TL;DR

This paper introduces a thermodynamic framework to quantify non-Markovian information flux in open quantum systems, linking information backflow to system-environment correlations and non-Markovianity.

Contribution

It proposes a thermodynamics-based definition of information flux and a protocol to analyze information sharing and correlations in static environments.

Findings

Information backflow characterizes non-Markovianity.

System-environment correlations build up over time.

Hierarchy of indivisibility relates to non-Markovian behavior.

Abstract

One of the fundamental issues in the field of open quantum systems is the classification and quantification of non-Markovianity. In the contest of quantity-based measures of non-Markovianity, the intuition of non-Markovianity in terms of information backflow is widely discussed. However, it is not easy to characterize the information flux for a given system state and show its connection to non-Markovianity. Here, by using the concepts from thermodynamics and information theory, we discuss a potential definition of information flux of an open quantum system, valid for static environments. We present a simple protocol to show how a system attempts to share information with its environment and how it builds up system-environment correlations. We also show that the information returned from the correlations characterizes the non-Markovianity and a hierarchy of indivisibility of the system dynamics.