Chaos control and exceptional point engineering via dissipative optomechanical coupling

Abstract

We study a dissipative mechanically coupled optomechanical system that hosts gain and loss. The gain (loss) is engineered by driving a purely dispersive optomechanical cavity with a blue-detuned (red-detuned) electromagnetic field. By taking into account the dissipative coupling, the Exceptional Point (EP), which is a non-Hermitain degeneracy, occurs at low threshold driving strength compared to what happens in a solely dispersive system. In the linear regime, the dissipative term induces strong coupling between the mechanical resonators, leading to an increase of energy exchange. For strong enough driving, the system enters into a nonlinear regime where a weak coupling regime takes place. In this regime, the mechanical resonators exhibit chaotic beats like-behaviour in the purely dispersive system. By switching on the dissipative coupling, the complex dynamics is switched off, and this restores regular dynamics into the system. This work suggests a way to probe quantum phenomena in dissipative systems at low-threshold driving strength. It also provides a new control scheme of complex dynamics in optomechanics and related fields.