Perspective: The Glass Transition

TL;DR

This perspective reviews the current state of the glass transition field, focusing on phenomenological facts, recent real space developments, and theoretical approaches aiming to understand the fundamental critical phenomena involved.

Contribution

It provides a comprehensive overview of recent advances and conceptual approaches in understanding the glass transition from a theoretical perspective.

Findings

Identification of key phenomenological characteristics of glass transition

Analysis of real space properties like dynamical heterogeneity and facilitation

Discussion of ensemble biasing methods to probe critical phenomena

Abstract

We provide here a brief perspective on the glass transition field. It is an assessment, written from the point of view of theory, of where the field is and where it seems to be heading. We first give an overview of the main phenomenological characteristics, or "stylised facts", of the glass transition problem, i.e. the central observations that a theory of the physics of glass formation should aim to explain in a unified manner. We describe recent developments, with a particular focus on real space properties, including dynamical heterogeneity and facilitation, the search for underlying spatial or structural correlations, and the relation between the thermal glass transition and athermal jamming. We then discuss briefly how competing theories of the glass transition have adapted and evolved to account for such real space issues. We consider in detail two conceptual and methodological approaches put forward recently, that aim to access the fundamental critical phenomenon underlying the glass transition, be it thermodynamic or dynamic in origin, by means of biasing of ensembles, of configurations in the thermodynamic case, or of trajectories in the dynamic case. We end with a short outlook.