Anomalous latent heat in non-equilibrium phase transitions

TL;DR

This paper investigates non-equilibrium first-order phase transitions in a two-temperature system, revealing an unusual positive latent heat when transitioning from higher to lower entropy phases, a phenomenon absent in equilibrium.

Contribution

It introduces the concept of anomalous latent heat in non-equilibrium phase transitions and demonstrates this effect using a lattice gas model with conflicting interactions.

Findings

Positive latent heat observed in non-equilibrium transitions

Effect depends on time-scale separation and conflicting interactions

Phenomenon specific to out-of-equilibrium conditions

Abstract

We study first-order phase transitions in a two-temperature system, where due to the time-scale separation all the basic thermodynamical quantities (free energy, entropy, etc) are well-defined. The sign of the latent heat is found to be counterintuitive: it is positive when going from the phase where the temperatures and the entropy are higher to the one where these quantities are lower. The effect exists only out of equilibrium and requires conflicting interactions. It is displayed on a lattice gas model of ferromagnetically interacting spin-1/2 particles.