Thermodynamics of the glassy state

TL;DR

This paper introduces a thermodynamic framework for the glassy state that incorporates an effective temperature parameter, resolving classical paradoxes and linking response functions with fluctuations in a generalized non-equilibrium context.

Contribution

It proposes a new thermodynamic description of glasses using an effective temperature, addressing longstanding paradoxes and connecting response and fluctuation relations.

Findings

Effective temperature explains Ehrenfest relations and Prigogine-Defay ratio.

Connects macroscopic response to fluctuations in a non-equilibrium setting.

Provides a unified thermodynamic approach to glassy states.

Abstract

A picture for thermodynamics of the glassy state is introduced. It assumes that one extra parameter, the effective temperature, is needed to describe the glassy state. This explains the classical paradoxes concerning the Ehrenfest relations and the Prigogine-Defay ratio. As a second part, the approach connects the response of macroscopic observables to a field change with their temporal fluctuations, and with the fluctuation-dissipation relation, in a generalized non-equilibrium way.