Finite size bath in qubit thermodynamics

TL;DR

This paper investigates the thermodynamics of a qubit coupled to a finite-size heat bath, analyzing heat and work statistics through models with either two-level systems or harmonic oscillators, and extends to open systems with infinite baths.

Contribution

It introduces a detailed analysis of heat and work in qubit systems coupled to finite baths, including models with different bath compositions and their coupling to infinite environments.

Findings

Derived heat and work statistics for finite-size baths.

Compared effects of different bath models on qubit thermodynamics.

Extended analysis to open systems with infinite baths.

Abstract

We discuss a qubit weakly coupled to a finite-size heat bath (calorimeter) from the point of view of quantum thermodynamics. The energy deposited to this environment together with the state of the qubit provides a basis to analyze the heat and work statistics of this closed combined system. We present results on two representative models, where the bath is composed of two-level systems or harmonic oscillators, respectively. Finally, we derive results for an open quantum system composed of the above qubit plus finite-size bath, but now the latter is coupled to a practically infinite bath of the same nature of oscillators or two-level systems.