Compressibility and pressure correlations in isotropic solids and fluids

TL;DR

This paper introduces simple models for isotropic solids and fluids across different dimensions to study pressure correlations under various thermodynamic constraints, providing insights into their compressibility and pressure fluctuations.

Contribution

It develops coarse-grained models that analyze pressure correlations in isotropic systems across multiple dimensions and constraints, a novel approach for understanding their thermodynamic behavior.

Findings

Pressure correlations depend on the ensemble and dimensionality.

The models reveal how ideal and excess pressure contributions relate.

Insights into compressibility and pressure fluctuations in isotropic systems.

Abstract

Presenting simple coarse-grained models of isotropic solids and fluids in $d=1$, $2$ and $3$ dimensions we investigate the correlations of the instantaneous pressure and its ideal and excess contributions at either imposed pressure (NPT-ensemble, $\lambda=0$) or volume (NVT-ensemble, $\lambda=1$) and for more general values of the dimensionless parameter $\lambda$ characterizing the constant-volume constraint.