Interference-induced enhancement of field entanglement in a   microwave-driven V-type single-atom laser
  We investigate the generation and the evolution of two-mode continuous-variable (CV) entanglement from system of a microwave-driven V-type atom in a quantum beat laser. By taking into account the effects of spontaneously generated quantum interference between two atomic decay channels, we show that the CV entanglement with large mean number of photons can be generated in our scheme, and the property of the filed entanglement can be adjusted by properly modulating the frequency detuning of the fields. More interesting, it is found that the entanglement can be significantly enhanced by the spontaneously generated interference. 
Wen-Xing Yang, Ai-Xi Chen, Ting-Ting Zha, Yanfeng Bai, and Ray-Kuang   Lee
quant-ph