玻色-爱因斯坦凝聚系统中原子的空间混沌分布

Spatially chaotic distribution of atoms in Bose-Einstein condensate systems

研究了非对称周期势阱中玻色-爱因斯坦凝聚原子的空间混沌分布结构.在凝聚体相位为常数的情况下,凝聚体内部不存在原子流,凝聚原子的空间分布结构可以用一个无阻尼双驱动Duffing方程描述.理论分析给出了原子间呈排斥作用系统的Melńikov混沌判据.数值模拟结果显示,化学势的增大能够对原子混沌分布产生明显的抑制作用,甚至使混沌完全消失.对于原子间呈吸引作用的系统,在一定参数条件下,调节光格势强度比可以使凝聚原子由周期状态进入到空间混沌分布状态,随着化学势的增大这种空间混沌分布被完全抑制.

In this paper,we study the spatially chaotic distribution of atoms in a Bose-Einstein condensate system,trapped in an asymmetric periodic potential.For a constant phase of condensate,without atom currents in the system,the space distributed structure of condensated atoms can be described by an undamped Duffing equation with double drivers.Through theoretical analyses,the Melńikov chaotic criterion for the system with a repulsive interatomic interaction is presented.Numerical simulations show that an increasing chemical potential can exert considerable suppression on the chaotic distribution of condensated atoms and even completely eliminate chaos.For a system with an attractive interatomic interaction,under some specific parametric conditions,adjusting the ratio between optical lattice potential amplitudes will force the condensated atoms from a periodic state into a spatially chaotic distribution;with the increase of chemical potential,the spatially chaotic distribution is completely suppressed.