Enhanced entanglement and steering in PT-symmetric cavity magnomechanics

We study creation of entanglement and quantum steering in a parity -time-(PT-) symmetric cavity magnomechanical system. There are photon-magnon coupling and phonon-magnon coupling in this system. By introducing a gain cavity mode, a PT-symmetric Hamiltonian of the system is obtained. We find that bipartite entanglement and magnon-*phonon steering in PT-symmetry system (gain-loss system) are significantly enhanced versus the case in the conventional cavity magnomechanical system (loss-loss system). Moreover, the magnon-*phonon one-way-like quantum steering can be realized in unbroken-PT-symmetry regime. The boundary of stability is demonstrated and it shows that the gain-loss system becomes more stable with respect to the conventional loss-loss system under the parameters we consider. This work opens up a route to explore the characteristics of quantum entanglement and steering in magnomechanical systems, which might have potential applications in quantum state engineering and quantum information.