Enhancement of Continuous Variable Entanglement in Four-Wave Mixing due to Atomic Memory Effects

Zhu Yu-Zhu, Xiangming Hu, Wang Fei +1 more

We explore the effects of atomic memory on quantum correlations of two-mode light fields from four-wave mixing. A three-level atomic system in Λ configuration is considered, in which the atomic relaxation times are comparable to or longer than the cavity relaxation times and thus there exists the atomic memory. The quantum correlation spectrum in the output is calculated without the adiabatic elimination of atomic variables. It is shown that the continuous variable entanglement is enhanced over a wide range of the normalized detuning in the intermediate and bad cavity cases compared with the good cavity case. In some situations more significant enhancement occurs at sidebands.

Saeid Vashahri-Ghamsari, Bing He, Min Xiao

Guangqiang He, Xuefei Wu, Yi Gu

We theoretically show that bright six-partite continuous-variable entanglement can be generated using cascaded four-wave mixing effects of third-order nonlinearity atomic systems above threshold. The six-partite continuous-variable entanglement among the six cavity fields with different frequencies is analyzed by applying optimized inseparability criteria proposed by Van Loock and Furusawa.

Wenxing Shi, Fei Wang, Lihui Zhang +2 more

Guangling Cheng, Wenxue Zhong, Aixi Chen

Yuan Sui-Hong, Xiangming Hu

This paper explores continuous variable entanglement in four-wave mixing when the atomic relaxation time is comparable to and longer than the cavity relaxation time. In this case the atomic memory is included in the field correlations and the entanglement in the output fields can be significantly enhanced. Einstein–Podolsky–Rosen (EPR) entanglement is achievable even in the bad cavity limit. This shows the EPR entanglement generation without need of good cavity.