自旋轨道耦合BEC系统中类Dicke模型的相变

Dicke-Type Phase Transition in a Spin-Orbit-Coupled Bose-Einstein condensate

本文研究了自旋轨道耦合玻色爱因斯坦凝聚(BEC)系统的基态性质,并把它映射为量子光学中我们所熟悉的Dicke模型(N个二能级原子与光场的相互作用).采用自旋相干态的方法得出系统的基态能量、光子数和自旋极化随拉曼耦合强度的变化关系,从而探测了系统超辐射相和正常相之间的量子相变.

In this paper,we study the ground state properties of the spin-orbit-coupled BEC by means of the spin coherent state transformation. And then we show that this system can be mapped to the well-known Dicke model in quantum optics,which describes the interactions between an ensemble of two-level atoms and an optical eld. In the picture of the spin coherent state,we are able to obtain the variation relation of the ground state energy,the spin polarization,and the photon number as a function of the Raman coupling strength. Consequently,the quantum phase transition between a superradiant phase and a normal phase is detected by these physical quantities.