Noise spectra of stochastic pulse sequences: application to large scale magnetization flips in the finite size 2D Ising model

TL;DR

This paper presents a method to predict noise spectra of stochastic pulse sequences, applied to large-scale magnetization flips in the 2D Ising model, revealing how phase transition dynamics influence noise characteristics.

Contribution

It introduces a general scheme to derive noise spectra from pulse parameter distributions and applies it to analyze magnetization noise in the 2D Ising model near criticality.

Findings

Low frequency noise dominated by system-wide magnetization flips.

Predicted spectra match simulation results.

High frequency spectra follow a power law related to critical exponents.

Abstract

We provide a general scheme to predict and derive the contribution to the noise spectrum of a stochastic sequence of pulses from the distribution of pulse parameters. An example is the magnetization noise spectra of a 2D Ising system near its phase transition. At $T\le T_c$, the low frequency spectra is dominated by magnetization flips of nearly the entire system. We find that both the predicted and the analytically derived spectra fit those produced from simulations. Subtracting this contribution leaves the high frequency spectra which follow a power law set by the critical exponents.