Relativistic motion through a thermal bath as a thermodynamic resource

TL;DR

This paper demonstrates that a quantum system in relativistic motion through a thermal bath naturally reaches non-Gibbs steady states, which can be exploited for work extraction and quantum energy storage.

Contribution

It reveals how relativistic motion alters thermalization, leading to novel non-Gibbs steady states with potential applications in quantum thermodynamics.

Findings

Relativistic motion prevents relaxation to Gibbs states.

Steady states include nonequilibrium currents and effective temperature states.

Potential for quantum batteries and work extraction.

Abstract

We show that a localized quantum system following an arbitrary stationary trajectory and weakly interacting with a stationary thermal bath of a massless scalar field is generically driven into a non-Gibbs steady state by relative motion alone, even without external driving or multiple baths. Relative motion between the system and the bath modifies the standard Kubo-Martin-Schwinger (KMS) relation, preventing relaxation to a Gibbs state. The resulting steady states fall into two distinct classes: (i) nonequilibrium steady states (NESS) with persistent probability currents, and (ii) current-free non-Gibbs steady states characterized by a frequency-dependent effective inverse temperature. We then focus on the simplest stationary trajectory, namely uniform relativistic motion with respect to a thermal bath. Using a three-level system as an illustrative example, we demonstrate that the former class can function as noisy stochastic clocks, while the latter possesses finite nonequilibrium free energy, enabling work extraction or storage, highlighting their potential as quantum batteries.