# A crossover in spatio-temporal correlations of strain fluctuations in glass forming liquids

## TL;DR

This study uses molecular dynamics simulations to reveal a crossover in the spatial correlations of strain fluctuations in glass-forming liquids, transitioning from power-law to exponential decay influenced by diffusion.

## Contribution

It uncovers a temperature- and time-dependent crossover in strain fluctuation correlations, linking the behavior to diffusion processes in glass-forming liquids.

## Key findings

- Strain correlations decay as 1/r^3 at long wavelengths.
- At intermediate distances, correlations decay exponentially.
- The crossover length scales with the diffusion coefficient and time.

## Abstract

Via molecular dynamics simulations of a generic glass former in the supercooled and normal liquid states, it is shown that spatial correlations of strain fluctuations exhibit a crossover from the well-established power-law $\sim 1/r^3$-decay at long wavelengths to an exponential behavior, $\sim \exp(-r/l_{\text {c}})$ at intermediate distances. The characteristic length of the exponential decay grows both with temperature and time via, $l_{\text {c}}^2 \propto D(T)\, t$, with $D(T)$ being the temperature-dependent diffusion coefficient. This suggests that the crossover between the power-law and exponential decays is governed by a diffusion process.