Generation of macroscopic quantum superpositions of optomechanical oscillators by dissipation

We propose a scheme that exploits the combined effects of nonlinear dynamics and dissipation to generate macroscopic quantum superpositions in massive optomechanical oscillators. The effective degenerate three-wave mixing interaction between the mechanical and optical cavity modes that results from quadratic optomechanical coupling, together with the cavity dissipation, can result in the existence of dark macroscopic superpositions. We show analytically and confirm numerically that various quantum superpositions can be achieved deterministically, depending on the initial state of the mechanics. The effects of mechanical damping are also studied in detail and quantified by the negativity of the Wigner function. The present scheme can be realized in various optomechanical systems with current technology.