Hyperuniformity in cyclically driven glasses

TL;DR

This paper investigates how cyclic shear deformation affects density fluctuations in a model glass, revealing hyperuniformity below yielding and phase separation with shear band formation above yielding.

Contribution

It demonstrates the emergence of hyperuniformity in glasses under cyclic shear and links it to a phase transition involving shear band formation.

Findings

Hyperuniformity occurs at low shear amplitudes below yielding.

Above yielding, density fluctuations are enhanced and phase separation occurs.

Shear band formation is associated with a transition to a non-hyperuniform state.

Abstract

We present a numerical investigation of the density fluctuations in a model glass under cyclic shear deformation. At low amplitude of shear, below yielding, the system reaches a steady absorbing state in which density fluctuations are suppressed revealing a clear fingerprint of hyperuniformity up to a finite length scale. The opposite scenario is observed above yielding, where the density fluctuations are strongly enhanced. We demonstrate that the transition to this state is accompanied by a spatial phase separation into two distinct hyperuniform regions, as a consequence of shear band formation above the yield amplitude.