On quantum and relativistic mechanical analogues in mean field spin models

TL;DR

This paper explores deep analogies between mean field spin models in statistical mechanics and classical or quantum mechanics, extending these analogies to a broad class of models and revealing their solvability through integrable PDEs.

Contribution

It extends the analogy between magnetic models and mechanical systems to a wide family of models classified by algebraic curves, showing their exact solvability.

Findings

Models are solvable via Hamilton-Jacobi type PDEs

Partition functions satisfy heat equations analogous to quantum wave functions

Relativistic analogs of Curie-Weiss models provide new insights

Abstract

Conceptual analogies among statistical mechanics and classical (or quantum) mechanics often appeared in the literature. For classical two-body mean field models, an analogy develops into a proper identification between the free energy of Curie-Weiss type magnetic models and the Hamilton-Jacobi action for a one dimensional mechanical system. Similarly, the partition function plays the role of the wave function in quantum mechanics and satisfies the heat equation that plays, in this context, the role of the Schrodinger equation in quantum mechanics. We show that this identification can be remarkably extended to include a wide family of magnetic models classified by normal forms of suitable real algebraic dispersion curves. In all these cases, the model turns out to be completely solvable as the free energy as well as the order parameter are obtained as solutions of an integrable nonlinear PDE of Hamilton-Jacobi type. We observe that the mechanical analog of these models can be viewed as the relativistic analog of the Curie-Weiss model and this helps to clarify the connection between generalised self-averaging and in statistical thermodynamics and the semi-classical dynamics of viscous conservation laws.