An autonomous quantum machine to measure the thermodynamic arrow of time

TL;DR

This paper proposes an autonomous quantum machine utilizing a quantum battery to measure entropy production and verify fluctuation theorems in quantum open systems, enabling experimental tests of thermodynamic irreversibility.

Contribution

It introduces a novel autonomous quantum machine that acts as a quantum work meter, linking energy fluctuations to entropy production and verifying fluctuation theorems in quantum thermodynamics.

Findings

Battery's energy fluctuations match work fluctuations

Verification of Jarzynski's equality in quantum systems

Feasible implementation with current opto-mechanical technology

Abstract

According to the Second Law of thermodynamics, the evolution of physical systems has a preferred direction, that is characterized by some positive entropy production. Here we propose a direct way to measure the stochastic entropy produced while driving a quantum open system out of thermal equilibrium. The driving work is provided by a quantum battery, the system and the battery forming an autonomous machine. We show that the battery's energy fluctuations equal work fluctuations and check Jarzynski's equality. Since these energy fluctuations are measurable, the battery behaves as an embedded quantum work meter and the machine verifies a generalized fluctuation theorem involving the information encoded in the battery. Our proposal can be implemented with state-of-the-art opto-mechanical systems. It paves the way towards the experimental demonstration of fluctuation theorems in quantum open systems.