Sakhel Roger R, Sakhel Asaad R
Department of Physics, Faculty of Science, Isra University, Amman 11622, Jordan.
Department of Physics, Faculty of Science, Balqa Applied University, Salt 19117, Jordan.
J Phys Condens Matter. 2020 May 6;32(31). doi: 10.1088/1361-648X/ab7f06.
We report parametric resonances (PRs) in a numerical investigation of a driven one-dimensional, interacting, and disordered Bose-Einstein condensate (BEC) confined in different traps. The BEC is excited by an oscillating Gaussian obstacle along a broad range of driving frequencies Ω. The PRs are detected via a quantity that is closely related to the time-average of the kinetic energy. The significant result of this work is that the trapping geometry plays a major role in defining the values of Ω at which PRs arise and controls their response to disorder. As such, it reveals the interplay of trapping geometry and disorder in these resonances. The dynamics of the modal coefficient() as well as that of the phase-mismatch() between the() and() are examined at and away from PR. At PR, |()| is generally found to be lower in magnitude than away from it, demonstrating that the atoms leave the= 0 ground state towards higher states. In the harmonic oscillator trap, the dynamic pattern of() is found to be quite robust against changes in the disorder strength contrary to the box potential. This is because in the box the ratio of the random-potential and kinetic energies is higher than in the harmonic trap signaling that the influence of disorder is weaker in the latter.
我们在对限制在不同势阱中的一维受驱动、相互作用且无序的玻色 - 爱因斯坦凝聚体（BEC）进行数值研究时报告了参量共振（PRs）。BEC 由沿广泛驱动频率 Ω 振荡的高斯障碍物激发。通过与动能时间平均值密切相关的量来检测 PRs。这项工作的重要结果是，捕获几何结构在确定出现 PRs 的 Ω 值以及控制它们对无序的响应方面起着主要作用。因此，它揭示了这些共振中捕获几何结构与无序之间的相互作用。在接近和远离 PR 时，研究了模态系数（）以及（）与（）之间的相位失配（）的动力学。在 PR 处，通常发现 |（）| 的大小比远离 PR 时更低，这表明原子从 = 0 的基态跃迁到更高的状态。在简谐振子势阱中，与方形势阱相反，发现（）的动态模式对无序强度的变化相当稳健。这是因为在方形势阱中，随机势与动能的比值高于简谐振子势阱，这表明无序在后者中的影响较弱。
