The Random First-Order Transition Theory of Glasses: a critical assessment

TL;DR

This paper critically reviews the Random First-Order Transition (RFOT) theory of glasses, discussing its foundations, predictions, and the challenges in validating it through theoretical and experimental means.

Contribution

It provides a comprehensive assessment of RFOT, clarifying its core concepts, predictions, and the role of fluctuations, while comparing it to other glass transition theories.

Findings

RFOT predicts the existence of an ideal glass state in small systems.

Fluctuations in finite dimensions complicate the transition between regimes.

New predictions on aging and non-linear rheology are proposed.

Abstract

The aim of this paper is to summarise the basic arguments and the intuition bolstering the RFOT picture for glasses, based on a finite dimensional extension of mean-field models with an exponentially large number of metastable states. We review the pros and cons that support or undermine the theory, and the directions, both theoretical and experimental, where progress is needed to ascertain the status of RFOT. We elaborate in particular on the notions of mosaic state and point-to-set correlations, and insist on the importance of fluctuations in finite dimensions, that significantly blur the expected cross-over between a Mode-Coupling like regime and the mosaic, activated regime. We discuss in detail the fundamental predictions of RFOT, in particular the possibility to force a small enough system into an ideal glass state, and present several new ones, concerning aging properties or non-linear rheology. Finally, we compare RFOT to other recent theories, including elastic models, Frustration Limited Domains or Kinetically Constrained models.