Phase dependence of entanglement generation in a PT-symmetric system of two micro-cavities

A system of two cavities connected by a single-mode fiber is considered. We investigate the generation of bipartite entanglement between cavities by calculating bipartite negativity. We show that the phase transition point of PT-symmetry strongly depends on the phase factor characterizing the propagation of photons in the fiber. The range of that phase factor in which the system is in the unbroken phase of PT-symmetry is estimated. We also indicate that the entanglement between cavities depends not only on the gain and loss of energy in the system but also on that phase factor. In addition, we show that, under a fine-tuning of the phase factor, our system can be a source of maximally entangled states.