Relativistic Quantum Thermal Machine: Harnessing Relativistic Effects to Surpass Carnot Efficiency

TL;DR

This paper demonstrates that relativistic motion can be exploited as a thermodynamic resource to enhance the efficiency of quantum thermal machines beyond classical limits, by leveraging Doppler effects on reservoir spectra.

Contribution

It introduces a relativistic quantum thermal machine model with Doppler reshaping of reservoir spectra, revealing new operational regimes and a generalized Carnot bound.

Findings

Operation beyond Carnot efficiency at finite power.

Doppler reshaping enables work extraction without temperature gradients.

Relativistic motion acts as a thermodynamic resource.

Abstract

We investigate a three-level maser quantum thermal machine in which the system-reservoir interaction is modeled via Unruh-DeWitt type coupling, with one or both reservoirs undergoing relativistic motion relative to the working medium. Motion induces Doppler reshaping of the reservoir spectra, modifying energy-exchange rates and enabling operation beyond the Carnot efficiency at finite power. We numerically analyze families of efficiency-power curves and extract the analytic form of a generalized Carnot bound, which recovers the Carnot limit. In addition, Doppler reshaping alters the boundaries between heat-engine and refrigerator operation, making it possible to extract positive work even in the absence of a temperature gradient. These findings establish relativistic motion as a genuine thermodynamic resource.