Thermodynamic state convertibility is determined by qubit cooling and heating

TL;DR

This paper investigates how quantum thermodynamic states can be converted through cooling and heating, revealing that the ability to manipulate qubits determines the interconversion of athermality resources.

Contribution

It demonstrates that the convertibility of quasi-classical thermodynamic resources is fully characterized by their capacity to cool and heat qubits, advancing the operational understanding of quantum thermodynamics.

Findings

Resource convertibility is determined by qubit cooling and heating capabilities.

Quasi-classical resource interconversion is fully characterized by these thermodynamic tasks.

The results unify thermodynamic state transformations through fundamental quantum processes.

Abstract

Thermodynamics plays an important role both in the foundations of physics and in technological applications. An operational perspective adopted in recent years is to formulate it as a quantum resource theory. At the core of this theory is the interconversion between athermality states, i.e., states out of thermal equilibrium. Here, we solve the question how athermality can be used to heat and cool other quantum systems that are initially at thermal equilibrium. We then show that the convertibility between quasi-classical resources (resources that do not exhibit coherence between different energy eigenstates) is fully characterized by their ability to cool and heat qubits, i.e., by two of the most fundamental thermodynamical tasks on the simplest quantum systems.