Non-linear dynamics of the non-Hermitian Su-Schrieffer-Heeger model

TL;DR

This paper explores the robustness of lasing edge modes in a non-Hermitian Su-Schrieffer-Heeger model, analyzing full non-linear and finite-temperature dynamics relevant for practical spin-torque oscillator applications.

Contribution

It extends previous linear studies by investigating non-linear and finite-temperature effects on topological edge modes in a non-Hermitian model.

Findings

Lasing edge modes persist across a broad parameter range.

Certain perturbations can destabilize the edge modes.

The model can be mapped onto a photonic system.

Abstract

We numerically determine the robustness of the lasing edge modes in a spin-torque oscillator array that realizes the non-Hermitian Su-Schrieffer-Heeger model. Previous studies found that the linearized dynamics can enter a topological regime in which the edge mode is driven into auto-oscillation, while the bulk dynamics are suppressed. Here we investigate the full non-linear and finite-temperature dynamics, whose understanding is essential for spin-torque oscillators-based applications. Our analysis shows that the lasing edge mode dynamics persist in the non-linear domain for a broad range of parameters and temperatures. We investigate the effects of perturbations relevant to experimental implementations and discuss which ones might be detrimental to the stability of the lasing edge mode. Finally, we map our model onto a photonic model. Our analysis has the potential to shed light onto the dynamics of a plethora of non-Hermitian systems with non-linearities.