Qubit-assisted enhancement of quantum entanglement in an optomechanical system in the presence of Kerr medium

In this work, we investigate a theoretical study of the stationary entanglement of an optomechanical system by adding a Kerr medium in the cavity where the mechanical resonator is perturbatively connected to an auxiliary qubit. The degree of entanglement between the cavity field and the mechanical system is measured by using the logarithmic negativity. We show that optomechanical entanglement is decreased by Kerr interaction due to photon blockage enhanced by mirror-qubit coupling, we also show that this enhancement is influenced by the temperature. In addition, we find that, in the presence of the mirror-qubit coupling, entanglement can arise with far weaker optomechanical coupling. The proposed scheme shows that the presence of the mirror-qubit coupling and Kerr medium is an effective control for an optomechanical system.