On the connection between microscopic description and memory effects in open quantum system dynamics

TL;DR

This paper explores how system-environment correlations and environmental evolution influence information flow and memory effects in open quantum systems, providing conditions for equivalent dynamics across different microscopic models.

Contribution

It derives conditions under which different microscopic models produce identical open-system dynamics and analyzes how correlations and environmental states affect information flow.

Findings

Different microscopic models can yield the same open-system dynamics.

System-environment correlations influence information flow.

Environmental state distinguishability impacts memory effects.

Abstract

The exchange of information between an open quantum system and its environment allows us to discriminate among different kinds of dynamics, in particular detecting memory effects to characterize non-Markovianity. Here, we investigate the role played by the system-environment correlations and the environmental evolution in the flow of information. First, we derive general conditions ensuring that two generalized dephasing microscopic models of the global system-environment evolution result exactly in the same open-system dynamics, for any initial state of the system. Then, we use the trace distance to quantify the distinct contributions to the information inside and outside the open system in the two models. Our analysis clarifies how the interplay between system-environment correlations and environmental-state distinguishability can lead to the same information flow from and toward the open system, despite significant qualitative and quantitative differences at the level of the global evolution.