We analytically solve two problems that may be useful in the context of the recent observation of matter wave bright solitons in a one-dimensional attractive atomic Bose gas. The first problem is strictly beyond mean field:
From the Bethe ansatz solution we extract the internal correlation function of the particle positions in the quantum soliton, that is for a fixed center of mass position. The second problem is solved in the limit of a large number of particles, where the mean field theory is asymptotically correct: It deals with the number of excitations created by the opening of the trap, starting from a pure soliton in a weakly curved harmonic potential.
Stabilization of bright solitons and vortex solitons in a trapless three-dimensional Bose-Einstein condensate by temporal modulation of the scattering length
We investigate the dynamics of a spin-orbit (SO) coupled BECs in a time dependent harmonic trap and show the dynamical system to be completely integrable by constructing the Lax pair. We then employ gauge transformation approach to witness the rapid oscillations of the condensates for a relatively smaller value of SO coupling in a time independent harmonic trap compared to their counterparts in a transient trap. Keeping track of the evolution of the condensates in a transient trap during its transition from confining to expulsive trap, we notice that they collapse in the expulsive trap. We fur…
Bright and dark solitons in a quasi 1D Bose-Einstein condensates modelled by 1D Gross-Pitaevskii equation with time-dependent parameters
在相互作用能远小于横向动能的假设下,研究了一维玻色-爱因斯坦凝聚体(BEC)的精确亮、暗孤波解.特别地,在文献Pérez-García等人[Physica D 221(2006)31]、Serkin等人[Phys. Rev. Lett. 98(2007)074102],Gürses [arXiv:0704.2435]和Kundu [Phys. Rev. E 79(2009)015601]的基础上,指出通过改变坐标和波函数的变量,可以将Gross-Pitaevskii(GP)方程导出的有效一维方程转化为具有完全可积的标准孤子(亮/暗)的一维非线性薛定谔(NLS)方程.我们分别考虑了束缚势和排斥势,并将原子散射长度、增益/损耗项和陷阱频率作为实验控制参数,将它们作为时间的函数进行调制。在陷阱频率不变的情况下,当原子的散射长度和增益/损耗项改变时,我们得到了不同类型的孤子解,如周期振荡孤子、凝聚体的崩塌和恢复、蛇形孤子、稳定孤子、孤子的增长和衰减以及双孤子束缚态的形成.然而,当陷阱频率也被调制时,我们显示的崩溃和复苏的双孤子的束缚态形成的双调制周期势和明亮和黑暗的孤子的阶梯调制势的凝聚体的现象。