Unraveling the success and failure of mode coupling theory from consideration of entropy

TL;DR

This paper investigates the relationship between mode coupling theory (MCT), the Adam-Gibbs relation, and entropy in supercooled liquids, providing a microscopic derivation and analyzing their mutual consistency near the critical temperature.

Contribution

It offers a microscopic derivation linking MCT, entropy, and Rosenfeld theory, and explores their interrelation in supercooled liquids.

Findings

AG relation predicts an avoided divergence at T_c

Pair configurational entropy vanishes at T_c

Residual multiparticle entropy influences relaxation time

Abstract

We analyze the dynamics of model supercooled liquids in a temperature regime where predictions of mode coupling theory (MCT) are known to be valid qualitatively. In this regime, the Adam-Gibbs (AG) relation, based on an activation picture of dynamics also describes the dynamics satisfactorily, and we explore the mutual consistency and interrelation of these descriptions. Although entropy and dynamics are related via phenomenological theories, the connection between MCT and entropy has not been argued for. In this work we explore this connection and provide a microscopic derivation of the phenomenological Rosenfeld theory. At low temperatures the overlap between MCT power law regime and AG relation implies that the AG relation predicts an avoided divergence at $T_c$, the origin of which is traced back to the vanishing of pair configurational entropy, which we find occurs at the same temperature. We also show that the residual multiparticle entropy plays an important role in describing the relaxation time