冷原子穿越激光束的量子隧穿时间

Quantum tunnelling time of cold atom passing through a laser beam

原子通过激光冷却技术能够被制备在低温状态,这时冷原子云会展现出量子力学的波动性.研究了一束冷原子入射到一个蓝失谐的激光束上所表现出的量子力学隧穿效应.蓝失谐的激光束相对于冷原子而言等效于一个量子力学势垒.根据二能级模型,在理论上分析了具有内部结构的原子矢量物质波穿过激光束的量子力学反射与透射,特别是对原子穿越激光束所需的时间——量子隧穿时间进行了详细的研究.量子力学波动性使得冷原子穿越一个激光束时明显地展现出与经典粒子(热原子)不同的结果.

Atoms can be prepared at low temperatures by laser cooling. The center of mass motion of the cold atoms exhibits wave nature of quantum mechanics. In this paper, we study the quantum tunneling effect of a cold atomic beam propagating through a laser beam which is blue detuned. The blue detuned laser beam is physically equal to a quantum potential barrier. According to two-level model of atom, we systematically analyze the quantum reflection and transmission of the vector atomic matter wave with internal structures propagating through a laser beam. Quantum tunneling time the atomic beam spends in transmitting the laser beam is studied in details. Because of quantum wave nature, cold atoms tunneling through a laser beam can obviously have a completely different feature from that of a classical particle （hot atom）.