# Many-body effects on the thermodynamics of closed quantum systems

## TL;DR

This paper investigates how many-body interactions influence the thermodynamics of closed quantum systems out-of-equilibrium, revealing that a simple approximation can effectively estimate work and entropy even with strong correlations.

## Contribution

It introduces a novel approximation method that accounts for many-body effects through initial states, simplifying the analysis of complex quantum thermodynamic processes.

## Key findings

- The approximation accurately estimates quantum work and entropy changes.
- Many-body correlations can be effectively captured by initial state considerations.
- The study provides insights into work extraction and entropy production across various regimes.

## Abstract

Thermodynamics of quantum systems out-of-equilibrium is very important for the progress of quantum technologies, however, the effects of many body interactions and their interplay with temperature, different drives and dynamical regimes is still largely unknown. Here we present a systematic study of these interplays: we consider a variety of interaction (from non-interacting to strongly correlated) and dynamical (from sudden quench to quasi-adiabatic) regimes, and draw some general conclusions in relation to work extraction and entropy production. As treatment of many-body interacting systems is highly challenging, we introduce a simple approximation which includes, for the average quantum work, many-body interactions only via the initial state, while the dynamics is fully non-interacting. We demonstrate that this simple approximation is surprisingly good for estimating both the average quantum work and the related entropy variation, even when many-body correlations are significant.