Entanglement and quantum coherence of two YIG spheres in a hybrid Laguerre-Gaussian cavity optomechanics.

We theoretically investigate continuous variable entanglement and macroscopic quantum coherence in the hybrid L-G rotational cavity optomechanical system containing two YIG spheres. In this system, a single L-G cavity mode and both magnon modes (which are due to the collective excitation of spins in two YIG spheres) are coupled through the magnetic dipole interaction whereas the L-G cavity mode can also exchange orbital angular momentum (OAM) with the rotating mirror (RM). We study in detail the effects of various physical parameters like cavity and both magnon detunings, environment temperature, optorotational and magnon coupling strengths on the bipartite entanglement and the macroscopic quantum coherence as well. We also explore parameter regimes to achieve maximum values for both of these quantum correlations. We also observed that the parameters regime for achieving maximum bipartite entanglement is completely different from macroscopic quantum coherence. So, our present study shall provide a method to control various nonclassical quantum correlations of macroscopic objects in the hybrid L-G rotational cavity optomechanical system and have potential applications in quantum sensing, quantum meteorology, and quantum information science.

Distant entanglement via photon hopping in a coupled cavity magnomechanical system.

We theoretically propose a scheme to generate distant bipartite entanglement between various subsystems in coupled magnomechanical systems where both the microwave cavities are coupled through single photon hopping coupling strength Γ. Each cavity contains a magnon mode and phonon mode and this gives six excitation modes in our model Hamiltonian which are cavity-1 photons, cavity-2 photons, magnon and phonon in cavity-1, and magnon and phonon in cavity-2. We found that significant bipartite entanglement exists between indirectly coupled subsystems in coupled microwave cavities for an appropriate set of parameters regime. Moreover, we also obtain suitable cavity and magnon detuning parameters for a significant distant bipartite entanglement in different bipartitions. In addition, it can be seen that a single photon hopping parameter significantly affects both the degree as well as the transfer of quantum entanglement between various bipartitions. Hence, our present study related to coupled microwave cavity magnomechanical configuration will open new perspectives in coherent control of various quantum correlations including quantum state transfer among macroscopic quantum systems.