Nonclassical mechanical states in cavity optomechanics in the single-photon strong-coupling regime

Generating nonclassical states of mechanical systems is a challenge relevant for testing the foundations of quantum mechanics and developing quantum technologies. Significant effort has been made to search for such states in the stationary behavior of cavity optomechanical systems. We focus instead on the transient dynamics. We find that in the single-photon strong-coupling regime the presence of an optical drive causes an initial mechanical coherent state to evolve to a nonclassical state, with a strongly negative Wigner function. An analytical treatment for a weak drive reveals that these states are quantum superpositions of coherent states. A numerical simulation shows that the presence of Wigner negativity is robust against weak dissipation.