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

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 autooscillation, 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.

Exceptional points as a route to magnetic nano-oscillators

“…The emergence of EPs does not, however, require a fine-tuned balance of gain and loss. EPs have been reported in a plethora of open systems, ranging from optics and photonics [4,6,13,16,17] to superconducting quantum circuits [18], semimetals [19][20][21][22], and magnetic systems [23][24][25][26][27][28][29][30][31].…”