arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2006.15239cond-mat.quant-gasnlin.CDnlin.PSphysics.flu-dyn
收藏

二元玻色-爱因斯坦凝聚体中二维量子turbulence的衰变

Decay of two-dimensional quantum turbulence in binary Bose-Einstein condensates

Mithun Thudiyangal, Kenichi Kasamatsu, Bishwajyoti Dey, Panayotis G. Kevrekidis

摘要:

通过数值模拟Gross-Pitaevskii方程,研究了谐波势阱和陡壁势阱中混溶二元玻色-爱因斯坦凝聚体中的二维量子湍流.湍流是通过高斯搅拌势产生的。当凝结体具有不相等的内部耦合强度或不对称的陷阱频率时,湍流凝结体经历剧烈的衰减动力学过程,形成交错排列的涡旋-反暗结构,即具有扩展涡核尺寸的类符号涡旋的准平衡态.当元件内耦合的参数不对称性或陷波频率增强时,这种状态的形成时间缩短。相应的不可压缩动能谱表现出两个值得注意的特征:(i)在由自旋恢复长度(扩展涡核的大小)确定的波数范围附近的$k^{-3}$幂律;(ii)在由密度恢复长度确定的波数范围附近的平坦区域。后者是与小尺度相位波动降级以外的的E-Fermi半径,是更突出的组件间相互作用的强度接近组件内的相互作用的强度。我们还研究了椭圆陡壁阱中组元间相互作用对类符号涡旋团簇形成的影响,发现组元间相互作用导致团簇构型的衰减.

英文摘要:

We study two-dimensional quantum turbulence in miscible binary Bose-Einstein condensates in either a harmonic trap or a steep-wall trap through the numerical simulations of the Gross-Pitaevskii equations. The turbulence is generated through a Gaussian stirring potential. When the condensates have unequal intra-component coupling strengths or asymmetric trap frequencies, the turbulent condensates undergo a dramatic decay dynamics to an interlaced array of vortex-antidark structures, a quasi-equilibrium state, of like-signed vortices with an extended size of the vortex core. The time of formation of this state is shortened when the parameter asymmetry of the intra-component couplings or the trap frequencies are enhanced. The corresponding spectrum of the incompressible kinetic energy exhibits two noteworthy features: (i) a $k^{-3}$ power-law around the range of the wave number determined by the spin healing length (the size of the extended vortex-core) and (ii) a flat region around the range of the wave number determined by the density healing length. The latter is associated with the small scale phase fluctuation relegated outside the Thomas-Fermi radius and is more prominent as the strength of intercomponent interaction approaches the strength of intra-component interaction. We also study the impact of the inter-component interaction to the cluster formation of like-signed vortices in an elliptical steep-wall trap, finding that the inter-component coupling gives rise to the decay of the clustered configuration.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑