Nonreciprocal bipartite and tripartite entanglement in cavity-magnon optomechanics via the Barnett effect

We theoretically propose a scheme for generating nonreciprocal macroscopic bipartite and tripartite entanglement using the Barnett effect in cavity-magnon optomechanics. The system consists of an optomechanical cavity and a rotatable yttrium iron garnet (YIG) sphere. Our results indicate that under appropriate parameter conditions, both bipartite entanglement and genuine tripartite entanglement can be generated between the cavity mode, mechanical mode, and magnon mode. Moreover, when the YIG sphere rotates, adjusting the magnetic field direction can induce a positive or negative Barnett shift, which leads to the nonreciprocity of entanglement, where entanglement exists in one chosen magnetic field direction and disappears in the other. Meanwhile, the macroscopic tripartite entanglement in the system is robust against thermal noise. Our work provides a possible avenue for quantum information processing, quantum chiral device integration, and multi-node quantum networks construction.