# Noise spectra in the reversible-irreversible transition in amorphous solids under oscillatory driving

## TL;DR

This paper investigates stress fluctuation spectra in amorphous solids under cyclic shear, revealing a broad 1/f-like noise spectrum above a critical amplitude and linking noise peaks to yielding, indicating a non-equilibrium phase transition.

## Contribution

It provides the first detailed analysis of noise spectra across the reversible-irreversible transition in amorphous solids under oscillatory driving.

## Key findings

- Stress fluctuations exhibit a broad 1/f^{b1}a0spectra in the irreversible regime.
- Low frequency noise peaks near the yielding stress.
- The results suggest a non-equilibrium phase transition at the critical amplitude.

## Abstract

We study the stress fluctuations in simulations of a two-dimensional amorphous solid under a cyclic drive. It is known that this system organizes into a reversible state for small driving amplitudes and remains in an irreversible state for high driving amplitudes, and that a critical driving amplitude separates the two regimes. Here we study the time series of the stress fluctuations below and above the reversible-irreversible transition. In the irreversible regime above the transition, the power spectrum of the stress fluctuations is broad and has a $1/f^{\alpha}$ shape with $1< \alpha <2$. We find that the low frequency noise power peaks near the stress at which dc yielding occurs, which is consistent with the behavior expected in systems undergoing a non-equilibrium phase transition.