Far-from-equilibrium thermodynamics of non-Abelian thermal states

Abstract

Noncommutativity of observables is a central feature of quantum physics. It plays a fundamental role in the formulation of the uncertainty principle for complementary variables and strongly affects the laws of thermodynamics for systems with noncommuting, that is, non-Abelian, conserved quantities. We here derive nonequilibrium generalizations of the second law of thermodynamics in the form of fluctuation relations, both for mechanically and thermally driven quantum systems. We identify a non-Abelian contribution to the energy and entropy balances, without which these relations would be violated. The latter term can be controlled to enhance both work extraction and nonequilibrium currents compared to what is obtained in commuting thermodynamics. These findings demonstrate that noncommutativity maybe a useful thermodynamic resource.