Qualitative features at the glass crossover

¹ Dipartimento di Fisica, Università “Sapienza” - Piazzale A. Moro 2, I-00185, Rome, Italy
² IPCF-CNR, UOS Rome, Università “Sapienza” - Piazzale A. Moro 2, I-00185, Rome, Italy
³ Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR) D-51170 Köln, Germany
⁴ Department of Physics, Heinrich-Heine-Universität Düsseldorf - Universitätsstraße 1, D-40225 Düsseldorf, Germany

Received: 20 May 2015
Accepted: 3 September 2015

Abstract

We discuss generic features of the dynamics of glass-forming liquids close to the glass transition singularity of the idealized mode-coupling theory (MCT). The analysis is based on a recent theory by one of the authors for the intermediate-time dynamics (β relaxation), derived by applying dynamical field-theory techniques to the idealized MCT. Taking the long-time asymptote of the β-relaxation regime as a proxy for universal aspects of the slow structural relaxation, we explain three prominent features of the dynamical crossover: the change from a power-law to exponential increase in the structural relaxation time, the replacement of the Stokes-Einstein relation between diffusion and viscosity by a fractional law, and two distinct growth regimes of the thermal susceptibility that has been associated to dynamical heterogeneities.