Quantum theory for pulse propagation in atomic ensembles
Ray-Kuang Lee1*
1Institute of Photonics Technologies, National Tsing-Hua University, Hsinchu, Taiwan
* presenting author:Ray-Kuang Lee, email:rklee@ee.nthu.edu.tw
A general quantum theory of pulse propagation in atomic ensembles is developed with quantum fluctuations of atoms taken into account. For two-level atomic ensembles, quantum correlation and quantum noise squeezing for self-induced transparency (SIT) solitons are demonstrated. For three-level atomic ensembles as electromagnetically-induced-transparency media, we derive the required Lengevin noise operator by satisfying the Bosonic commutation relation for quantized probe field. Theoretical results on the degradation of quantum noises give agreement both to the experimental reports in the literature for the slow-light and light-storage-retrieval demonstrations with squeezed vacuum pulses.
Based on such a fully quantum mechanical approach, this study provides a deeper understanding in the quantum memory with squeezed light sources, and can also be applied to the related quantum information processing.

Keywords: Quantum noises, photon-atom interaction, EIT, SIT