Aging in a Model of Self-Organized Criticality

TL;DR

This paper investigates aging phenomena in the Bak-Sneppen model of self-organized criticality, revealing non-stationary dynamics with distinct power-law decay regimes and introducing a new critical exponent for late-time behavior.

Contribution

It demonstrates aging in self-organized critical systems and identifies a novel critical exponent for non-stationary avalanche dynamics.

Findings

Autocorrelation functions exhibit aging similar to glassy systems.

Decay follows two power-law regimes separated by the avalanche age.

A new critical exponent characterizes late-time non-stationary behavior.

Abstract

Temporal autocorrelation functions for avalanches in the Bak-Sneppen model display aging behavior similar to glassy systems. Numerical simulations show that they decay as power laws with two distinct regimes separated by a time scale which is the waiting time, or age, of the avalanche. Thus, time-translational invariance is dynamically broken. The critical exponent of the initial decay is that of the familiar stationary dynamics while a new critical exponent for the late-time behavior appears. This new exponent characterizes a non-stationary regime that has not been previously considered in the context of self-organized criticality.