Mode attraction in Floquet systems with memory: application to magnonics

TL;DR

This paper explores mode attraction phenomena in Floquet systems with memory, demonstrating its occurrence in nonlinear driven systems like cavity magnonics, and provides a formalism applicable to quantum and semiclassical magnetic dynamics.

Contribution

It introduces a general formalism for mode attraction in Floquet systems with memory and applies it to cavity magnonics, bridging nonlinear driven dynamics and experimental systems.

Findings

Mode attraction can occur in Floquet systems with memory.

Magnetic excitations far from equilibrium can exhibit level attraction with cavity photons.

The developed theory is compatible with micromagnetic simulations.

Abstract

Level attraction is a type of mode hybridization in open systems where instead of forming a hybridization gap, the energy spectrum of two modes coalesce in a region bounded by exceptional points. We demonstrate that this phenomenon can be realized in a Floquet system with memory, which appears in describing linear excitations in a nonlinear driven system with a limit cycle. Linear response of the system in this state is different from its response near thermodynamic equilibrium. We develop a general formalism and provide an example in the context of cavity magnonics, where we show that magnetic excitations in systems driven far from the equilibrium may show level attraction with cavity photons. Our approach works equally well for quantum and semiclassical magnetic dynamics. The theory is formulated so that it can be used in combination with micromagnetic simulations to explore a wide range of experimentally interesting systems.