Irreversibility as divergence from equilibrium
arXiv:2404.01978 · doi:10.1007/s10955-025-03528-4
Abstract
The entropy production is commonly interpreted as measuring the distance from equilibrium. However, this explanation lacks a rigorous description due to the absence of a natural equilibrium measure. The present analysis formalizes this interpretation by expressing the entropy production of a Markov system as a divergence with respect to particular equilibrium dynamics. These equilibrium dynamics correspond to the closest reversible systems in the information-theoretic sense. This result yields novel links between nonequilibrium thermodynamics and information geometry.