mathcal{PT}-Symmetry-Breaking Chaos in Optomechanics

We demonstrate a $\mathcal{PT}$-symmetry-breaking chaos in optomechanical system (OMS), which features an ultralow driving threshold. In principle, this chaos will emerge once a driving laser is applied to the cavity mode and lasts for a period of time. The driving strength is inversely proportional to the starting time of chaos. This originally comes from the dynamical enhancement of nonlinearity by field localization in $\mathcal{PT}$-symmetry-breaking phase ($\mathcal{PT}$BP). Moreover, this chaos is switchable by tuning the system parameters so that a $\mathcal{PT}$-symmetry phase transition occurs. This work may fundamentally broaden the regimes of cavity optomechanics and nonlinear optics. It offers the prospect of exploring ultralow-power-laser triggered chaos and its potential applications in secret communication.