# Clausius inequality versus quantum coherence

## TL;DR

This paper investigates how quantum coherence affects thermodynamic behavior in a harmonic oscillator system interacting with a thermal bath, revealing violations of the Clausius inequality linked to coherence rather than entanglement.

## Contribution

It demonstrates that quantum coherence can cause violations of the Clausius inequality, challenging traditional thermodynamic assumptions in quantum systems.

## Key findings

- Coherence persists at low temperatures during thermal bath interaction.
- Clausius inequality is violated despite maintained coherence.
- Violation is attributed to coherence, not entanglement.

## Abstract

In this study, we model a harmonic oscillator that enters an interferometer partially coupled to a thermal bath of oscillatory fields by employing a Brownian-type Lindblad master equation. More specifically, we investigate the dynamics and the variations of the thermodynamic quantities of the system at different temperatures. We recognize that although the system can remain coherent during its interaction with the thermal bath in the low-temperature limit, the system's entropy production violates the Clausius inequality. Furthermore, we argue that the system's coherence is the source of this violation, rather than the entanglement degree of system-environment, as reported in previous studies.