Entropy production in non-Markovian collision models: Information backflow vs system-environment correlations

TL;DR

This paper explores how non-Markovian dynamics influence entropy production in a qubit system, revealing that system-environment correlations, not just information backflow, are key to negative entropy production rates.

Contribution

It distinguishes the roles of information backflow and system-environment correlations in entropy production, showing correlations are crucial for negative rates.

Findings

Correlations between system and environment lead to negative entropy production rates.

Models preserving system-environment correlations exhibit negative entropy production.

Non-Markovian dynamics alone do not guarantee negative entropy production.

Abstract

We investigate the irreversible entropy production of a qubit in contact with an environment modelled by a microscopic collision model both in Markovian and non-Markovian regimes. Our main goal is to contribute to the discussions on the relationship between non-Markovian dynamics and negative entropy production rates. We employ two different types of collision models that do or do not keep the correlations established between the system and the incoming environmental particle, while both of them pertain to their non-Markovian nature through information backflow from the environment to the system. We observe that as the former model, where the correlations between the system and environment is preserved, gives rise to negative entropy production rates in the transient dynamics, the latter one always maintains positive rates, even though the convergence to the steady-state value is slower as compared to the corresponding Markovian dynamics. Our results suggest that the mechanism underpinning the negative entropy production rates is not solely non-Markovianity through information backflow, but rather the contribution to it through established system-environment correlations.