Record Dynamics: Direct Experimental Evidence from Jammed Colloids

TL;DR

This paper provides the first direct experimental evidence supporting record dynamics in jammed colloids, showing that rare quake events control aging and their rate decreases inversely with system age, aligning with theoretical predictions.

Contribution

It offers the first experimental verification of the quake statistics assumption in record dynamics within jammed colloids, confirming the decelerating quake rate over time.

Findings

Quake rate decreases inversely with system age.

Mean square displacement grows logarithmically with time.

Mesoscopic lengthscale increases logarithmically with time.

Abstract

In a broad class of complex materials a quench leads to a multi-scaled relaxation process known as aging. To explain its commonality and the astounding insensitivity to most microscopic details, record dynamics (RD) posits that a small set of increasingly rare and irreversible events, so called quakes, controls the dynamics. While key predictions of RD are known to concur with a number of experimental and simulational results, its basic assumption on the nature of quake statistics has proven extremely difficult to verify experimentally. The careful distinction of rare ("record") cage-breaking events from in-cage rattle accomplished in previous experiments on jammed colloids, enables us to extract the first direct experimental evidence for the fundamental hypothesis of RD that the rate of quakes decelerates with the inverse of the system age. The resulting description shows the predicted growth of the particle mean square displacement and of a mesoscopic lengthscale with the logarithm of time.