Configurations and Observables in an Ising Model with Heat Flow

TL;DR

This paper investigates a 2D Ising model under heat flow, revealing steady states with coexisting phases and analyzing how heat influences fluctuations in thermodynamic and geometrical observables.

Contribution

It introduces the application of KQ dynamics to study non-equilibrium steady states and explores the impact of heat flow on phase coexistence and observable fluctuations.

Findings

Heat flow induces coexisting phases transversal to the heat gradient.

Fluctuations of thermodynamic and geometrical observables are amplified near the critical energy.

Dependence of fluctuations on system size, thermal gradient, and interactions is discussed.

Abstract

We study a two dimensional Ising model between thermostats at different temperatures. By applying the recently introduced KQ dynamics, we show that the system reaches a steady state with coexisting phases transversal to the heat flow. The relevance of such complex states on thermodynamic or geometrical observables is investigated. In particular, we study energy, magnetization and metric properties of interfaces and clusters which, in principle, are sensitive to local features of configurations. With respect to equilibrium states, the presence of the heat flow amplifies the fluctuations of both thermodynamic and geometrical observables in a domain around the critical energy. The dependence of this phenomenon on various parameters (size, thermal gradient, interaction) is discussed also with reference to other possible diffusive models.