Height distribution of elastic interfaces in quenched random media

TL;DR

This paper studies the height distribution of elastic interfaces in quenched random media, showing the robustness of negative skewness at depinning and describing how the distribution evolves with increasing external force.

Contribution

It demonstrates the robustness of negative skewness at depinning across different elasticity regimes and analyzes the evolution of height distribution as force approaches criticality.

Findings

Negative skewness persists at depinning in mean-field elasticity.

Height distribution shifts from symmetric to positively skewed before becoming negatively skewed.

Distribution evolution characterizes the depinning transition process.

Abstract

Elastic interfaces in quenched random media driven by external forces exhibit a continuous depinning phase transition between pinned and moving phases at a critical external force. Recent work [Phys. Rev. Lett. 129, 175701 (2022)] has shown that the distribution of local interface heights at depinning displays negative skewness. Here, by considering local, long-range and fully-coupled (mean-field) elasticity, we expand on this result by demonstrating the robustness of the negative skewness at depinning when approaching the thermodynamic limit and considering different values of the spring stiffness controlling the avalanche cutoff. Additionally, we investigate the evolution of the height distribution as the external force is ramped up from zero, approaching the critical force from below. Starting from a symmetric height distribution at zero force, the distribution initially develops positive skewness increasing with the external force, followed by a steep drop to the negative value characteristic of the critical point as the depinning transition is reached.