# Activity statistics in a colloidal glass former: experimental evidence for a dynamical transition

## TL;DR

This study investigates the dynamics of dense colloidal suspensions near the glass transition, revealing a potential dynamic phase transition through analysis of local activity and its statistical properties.

## Contribution

It provides experimental evidence linking local activity fluctuations to a dynamical transition in colloidal glasses, highlighting rare low-activity events associated with glassy behavior.

## Key findings

- Identification of a low activity tail in activity statistics
- Correlation between rare events and glassy dynamics
- Evidence supporting a dynamic phase transition

## Abstract

In a dense colloidal suspension at a volume fraction slightly lower than that of its glass transition, we follow the trajectories of an assembly of tracers over a large time window. We define a local activity, which quantifies the local tendency of the system to rearrange. We determine the statistics of the time and space integrated activity, and we argue that it develops a low activity tail that comes on a par with the onset of glassy behavior and heterogeneous dynamics. These rare events may be interpreted as the reflection of an underlying dynamic phase transition.