Effect of the dispersion on multipartite continuous-variable entanglement in optical parametric amplifier**Project supported by the State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China (Grant No. KF201401) and the National Natural Science Foundation of China (Grant No. 11404084).

Abstract

Based on the quantum fluctuations, we adopt the method of generalized V1 criterion to investigate multipartite entanglement characteristics in an optical parametric amplification system with the consideration of dispersion. The nonlinear interaction becomes strong because of the existence of dispersion coefficient σ . Considering the influence of dispersion factor σ , with increasing the pump parameter μ , the value of minimum variance V1 decreases and the squeezing curve nearly equals 1/(1 + μ ). The larger particle number N results in a smaller variance and higher entanglement.