Quantum optomechanics beyond linearization

The quantum dynamics of optomechanical systems has mostly been studied to determine the fluctuations around classical steady states. We present a theoretical approach to determining the system observables of optomechanical systems as genuine quantum objects, for example, a quantum-mechanical oscillator coupled to a cavity single photon. In this approach we study the dynamics of such systems in the strong-coupling regime. We find that, under strong optomechanical coupling, steady quantum states of optomechanical systems driven by continuous-wave single photons exhibit periodic oscillation, and cavity noise considerably affects the system observables.