Unconventional entropy production in the presence of momentum-dependent forces

TL;DR

This paper explores a novel form of entropy production in nonequilibrium systems with momentum-dependent forces, revealing an unconventional contribution that ensures the second law's validity.

Contribution

It introduces the concept of unconventional entropy production arising from momentum-dependent forces in systems with odd-parity variables, expanding understanding of thermodynamic irreversibility.

Findings

Unconventional entropy production exists in systems with momentum-dependent forces.

Additional entropy contribution is crucial for the non-negativity of total entropy production.

Examples demonstrate the impact of momentum-dependent forces on entropy dynamics.

Abstract

We investigate an unconventional nature of the entropy production (EP) in nonequilibrium systems with odd-parity variables that change signs under time reversal. We consider the Brownian motion of a particle in contact with a heat reservoir, where particle momentum is an odd-parity variable. In the presence of an {\it external} momentum-dependent force, the EP transferred to environment is found {\em not} equivalent to usual reservoir entropy change due to heat transfer. There appears an additional unconventional contribution to the EP, which is crucial for maintaining the non-negativity of the (average) total EP enforced by the thermodynamic second law. A few examples are considered to elucidate the novel nature of the EP. We also discuss detailed balance conditions with a momentum-dependent force.