Title: Continuous-variable entangled light sources generated from coherent atomic media

 

Abstract:

 

Quantum entanglement is an essential ingredient for potential applications in quantum communication, quantum computation, quantum information sciences etc. Compared with other quantum objects, photon travelling with speed of light in vacuum and being not affected by surrounding environments shows that it is an ideal quantum carrier in quantum age. On the other hand, the mature techniques in ultracold atom experiments provide a powerful tool to control and study atom-light interactions. Combining the advantages in the two aspects, we are motivated to study the non-classical light generations from coherent interactions between light and atomic systems. In this talk, I will introduce our propose scheme to generate continuous-variable entanglement or two-mode squeezed state of light by using the coherent atomic media - electromagnetically induced transparency (EIT). This proposed scheme is more efficient than the conventional one, which utilizes the ground state relaxation rate (or dephasing rate) to produce entanglement. The maximum degree of entanglement at a given optical density can be 
achieved with a wide range of the coupling Rabi frequency and the two-photon detuning, showing our scheme is robust and flexible. In addition, it exists an optimum ratio of the probe to coupling Rabi frequencies in EIT system to achieve the maximum entanglement.