Dynamical correlations in a glass-former with randomly pinned particles

TL;DR

This study investigates how randomly pinning particles affects the dynamical heterogeneity in a glass-forming fluid, revealing that pinning significantly increases relaxation time without notably changing correlation length.

Contribution

It introduces a real-space analysis method for four-point correlations in pinned glass-formers, providing new insights into the glass transition mechanisms.

Findings

Relaxation time increases up to two decades with pinning.

Four-point correlation length remains nearly unchanged despite pinning.

Implications for theories of the glass transition are discussed.

Abstract

The effects of randomly pinning particles in a model glass-forming fluid are studied, with a focus on the dynamically heterogeneous relaxation in the presence of pinning. We show how four-point dynamical correlations can be analysed in real space, allowing direct extraction of a length scale that characterises dynamical heterogeneity. In the presence of pinning, the relaxation time of the glassy system increases by up to two decades, but there is almost no increase in either the four-point correlation length or the strength of the four-point correlations. We discuss the implications of these results for theories of the glass transition.