原子芯片上指数型布居增长的原子输运

Atom Transport with Exponentially Growing Population on an Atom Chip

超冷原子体系中要观测增益平衡的宇称-时间(PT)对称,需产生受控的原子布居增益/损耗及相干耦合。本文提出了动态控制原子芯片上双阱中原子输运实现原子布居指数增长的方法。采用直接蒙特卡罗方法数值研究了原子系综在双阱间的输运动力学,发现初始原子数和温度会显著影响输运效果,如目标势阱中的原子布居增益速率和转移效率。此外,还细致分析了左侧势阱抬升时间对右侧势阱中原子布居增长趋势的影响效果。该方案为在超冷原子气体中实现有增益/损耗的PT对称量子体系提供了切实可行的方法。

In the ultracold atomic system,to observe the Parity-Time（PT）symmetry with the gain balance requires controlled gain/loss of atom population and coherent coupling.We present a proposal to obtain an exponential growth of the atom population by dynamically controlling atom transport in a double-well trap on an atom chip.We numerically investigate the transport dynamics of the atomic ensemble between the sub-wells by using the direct simulation Monte Carlo method.It is found that the initial number and temperature of the atom cloud remarkably affect the transport performance,such as gain rate and transfer efficiency of the atom population in the target trap.Moreover,the effect of the lifting time of the left-well on the growing trend of the atom population in the right-well is analyzed in detail.Our strategy provides an achievable way for realizing a PT symmetric quantum system with gain/loss in ultracold atomic gas.