Physical Review A
Entanglement between collective fields via phase-dependent electromagnetically induced transparency
Fei Wang, Xiangming Hu, Wenxing Shi, Zhu Yu-Zhu
Abstract
We show that it is possible to obtain continuous variable entanglement for four optical fields via phase-dependent electromagnetically induced transparency in a four-level system in double-$\ensuremath{\Lambda}$ configuration. Due to quantum interference, the four fields constitute two quantum beats, behave as a pair of collective modes, and experience high cross Kerr nonlinearities. As a result, entanglement occurs between the two collective modes and between any two individual fields from the different collective modes.