Pairwise entanglement in a three-cavity optomechanical system

Abstract

Understanding the behavior of quantum entanglement in a multipartite quantum system has deep applications in quantum communication. Here, we study the pairwise entanglement between mechanical modes in an optomechanical system consisting of three distant Fabry-Pérot cavities driven by three independent coherent lasers and mutually fed by two-mode squeezed light. We observe that the degree of quantum entanglement, quantified by means of the logarithmic negativity, between any two mechanical modes increases by enhancing the squeezing parameter characterizing the two-mode squeezed light feeding the two corresponding cavities. On the other hand, we show that increasing the irrelevant squeezing parameters reduces the considered pairwise entanglement. In this way, one can control the pairwise entanglement in the optomechanical system by properly manipulating the squeezing parameters. Moreover, the optimal amount of entanglement is obtained for equal optomechanical couplings.