Mean field spin glasses treated with PDE techniques

TL;DR

This paper introduces a PDE-based approach to analyze mean field spin glasses, specifically the SK model, linking PDE techniques to statistical mechanics to derive free energy expressions and phase transition insights.

Contribution

It presents a novel PDE methodology for solving the SK model at different replica symmetry levels, connecting PDE symmetries with statistical mechanics constraints and deriving new polynomial identities.

Findings

Derived free energy expressions using PDE analogies.

Identified shock wave formation at critical noise levels indicating phase transitions.

Established new polynomial identities related to overlap organization.

Abstract

Following an original idea of F. Guerra, in this notes we analyze the Sherrington-Kirkpatrick model from different perspectives, all sharing the underlying approach which consists in linking the resolution of the statistical mechanics of the model (e.g. solving for the free energy) to well-known partial differential equation (PDE) problems (in suitable spaces). The plan is then to solve the related PDE using techniques involved in their native field and lastly bringing back the solution in the proper statistical mechanics framework. Within this strand, after a streamlined test-case on the Curie-Weiss model to highlight the methods more than the physics behind, we solve the SK both at the replica symmetric and at the 1-RSB level, obtaining the correct expression for the free energy via an analogy to a Fourier equation and for the self-consistencies with an analogy to a Burger equation, whose shock wave develops exactly at critical noise level (triggering the phase transition). Our approach, beyond acting as a new alternative method (with respect to the standard routes) for tackling the complexity of spin glasses, links symmetries in PDE theory with constraints in statistical mechanics and, as a novel result from the theoretical physics perspective, we obtain a new class of polynomial identities (namely of Aizenman-Contucci type but merged within the Guerra's broken replica measures), whose interest lies in understanding, via the recent Panchenko breakthroughs, how to force the overlap organization to the ultrametric tree predicted by Parisi.