Bloch Oscillations of Two-Component Bose-Einstein Condensates in Optical Lattices

We study the Bloch oscillations of two-component Bose-Einstein condensates trapped in spin-dependent optical lattices. The influence of the intercomponent atom interaction on the system is discussed in detail Accelerated breakdown of the Bloch oscillations and revival phenomena are found respectively for the repulsive and attractive case. For both the cases, the system will finally be set in a quantum self-trapping state due to dynamical instability.     

双色驻波场中梯形三能级原子所受整流偶极力的涨落分析

本文基于文献[1]利用双色驻波场作用于三能级原子获得宏观数量个光学波长上符号保持不变的整流偶极力的工作基础上,运用量子回归定理计算了所得整流偶极力在一个光学波长上的涨落.结果表明:原子偶极零点振动与光场幅度梯度相互作用引起的偶极力的涨落D1的值较大,是整流偶极力涨落的主要因素,且其随空间的变化规律与整流偶极力相似;原子偶极与真空零点振动相互作用导致偶极力的涨落Ds较小,几乎可以忽略不计.由于力的起伏所导致的加热效应不利于中性原子的偶极束缚[6].     

Radiation pressure and laser cooling of a three-level atom in a ladder configuration

Radiation pressure and laser cooling of a moving three-level ladder-type atom in bichromatic travelling fields are considered. The dependence of the force on parameters such as detunings, Rabi frequencies and spontaneous decay rates is calculated numerically and shown graphically, and analytical expressions for the force are obtained for some special parameter values. It is shown that the radiation pressure shows Doppler-shifted resonance peaks resulting respectively from one-photon and two-photon transitions. Using the present scheme, Doppler cooling of sodium exploiting the 3{}^2S_{1/2}－3{}^2P_{3/2}－3{}^2D_{5/2} cascade transitions is investigated. It is found that temperatures lower than the Doppler limit can be achieved.