Cooling of optomechanical system by coherent feedback

A new method based on coherent feedback control theory is proposed to cool the optomechanical resonator. In this study, we focus on the weak-driving strong-coupling two-mode optomechanical system, which creates nonlinear coupling regime between cavity modes and the mechanical mode. By means of our design, two cavity resonators are coherently connected with each other, which constructs a closed quantum feedback loop. In the framework of SLH notation, we obtained the Hamiltonian and master equation of the two-mode optomechanical system. The numerical simulation shows that the method is efficient for cooling the mechanical resonators to the ground state.