Aging is a log-Poisson Process, not a Renewal Process

TL;DR

This paper argues that aging in disordered materials follows a log-Poisson process driven by record-breaking fluctuations, challenging the traditional renewal process models like CTRW, and offers a universal, physically grounded description of aging dynamics.

Contribution

It introduces a record dynamics model based on log-Poisson statistics as a universal description of aging, contrasting with traditional renewal process approaches.

Findings

Aging dynamics in jammed matter follow a log-Poisson process.

Record-breaking fluctuations ('quakes') drive the intermittent aging process.

The proposed model aligns with experimental observations in colloids and disordered magnets.

Abstract

Aging is a ubiquitous relaxation dynamic in disordered materials. It ensues after a rapid quench from an equilibrium "fluid" state into a non-equilibrium, history-dependent jammed state. We propose a physically motivated description that contrasts sharply with a continuous-time random walk (CTRW) with broadly distributed trapping times commonly used to fit aging data. A renewal process like CTRW proves irreconcilable with the log-Poisson statistic exhibited, for example, by jammed colloids as well as by disordered magnets. A log-Poisson process is characteristic of the intermittent and decelerating dynamics of jammed matter usually activated by record-breaking fluctuations ("quakes"). We show that such a record dynamics (RD) provides a universal model for aging, physically grounded in generic features of free-energy landscapes of disordered systems.