Diffusion coefficient power laws and defect-driven glassy dynamics in swap acceleration

TL;DR

This paper investigates how particle swaps influence glassy dynamics, revealing power-law scaling of diffusion coefficients with swap fraction and supporting defect models of the glass transition.

Contribution

It introduces a partial swappability model with a fraction of swap-initiating particles and uncovers their role in glassy dynamics and defect formation.

Findings

Diffusion coefficients scale with swap fraction via unexpected power laws.

Swap-initiators act as defect particles inducing glassy behavior.

Results support defect models of the glass transition.

Abstract

Particle swaps can drastically accelerate dynamics in glass. The mechanism is expected to be vital for a fundamental understanding of glassy dynamics. To extract defining features, we propose a partial swappability with a fraction {\phi_s} of swap-initiating particles, which can only swap locally with each other or with regular particles. We focus on the swap-dominating regime. At all temperatures studied, particle diffusion coefficients scale with {\phi_s} in unexpected power laws with temperature-dependent exponents, consistent with the kinetic picture of glass transition. At small {\phi_s}, swap-initiators, becoming defect particles, induce remarkably typical glassy dynamics of regular particles. This supports defect models of glass.