Perturbation Theory for Classical Solids

TL;DR

This paper introduces the first rigorous perturbation theory for classical solids, improving upon previous methods by accurately describing thermodynamic and structural properties across the phase diagram.

Contribution

It develops a first-order perturbation approach based on a solid reference structure, overcoming previous difficulties and unifying the description of solid and liquid phases.

Findings

Accurate thermodynamic predictions for model solids

Consistent phase diagram representation

Improved structural property calculations

Abstract

The first well founded perturbation theory for classical solid systems is presented. Theoretical approaches to thermodynamic and structural properties of the hard-sphere solid provide us with the reference system. The traditional difficulties of all previous approaches are overcome. The perturbation is a first order term in an expansion of the Helmholtz free energy functional instead of an additive {\it ad hoc} term and the proper solid reference structure is used instead of some kind of mapping into the fluid structure at some effective density. As the theory reduces to the usual liquid perturbation theory in the uniform limit, it can describe consistently the complete phase diagram. Excellent results are obtained when applied to different model systems.