Macroscopic fluctuations theory of aerogel dynamics

TL;DR

This paper develops a macroscopic fluctuation theory for aerogel dynamics, revealing non-analytic thermodynamic potentials that suggest possible non-equilibrium phase transitions due to particles with low speeds.

Contribution

It introduces a novel thermodynamic potential framework for Hamiltonian models including aerogels, highlighting non-analyticity and non-convexity absent in previous models.

Findings

Thermodynamic potential is non-analytic and non-convex.

Energy current is carried by particles with arbitrarily low speeds.

Potential indicates possible non-equilibrium phase transitions.

Abstract

We consider the thermodynamic potential describing the macroscopic fluctuation of the current and local energy of a general class of Hamiltonian models including aerogels. We argue that this potential is neither analytic nor strictly convex, a property that should be expected in general but missing from models studied in the literature. This opens the possibility of describing in terms of a thermodynamic potential non-equilibrium phase transitions in a concrete physical context. This special behaviour of the thermodynamic potential is caused by the fact that the energy current is carried by particles which may have arbitrary low speed with sufficiently large probability.