Qi Xiu-Ying, Xue Ju-Kui
Key Laboratory of Atomic & Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronics Engineering, Northwest Normal University, Lanzhou 730070, China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2012 Jul;86(1 Pt 2):017601. doi: 10.1103/PhysRevE.86.017601. Epub 2012 Jul 2.
We consider the modulational instability (MI) of Bose-Einstein condensate (BEC) described by a modified Gross-Pitaevskii (GP) equation with higher-order nonlinearity both analytically and numerically. A new explicit time-dependent criterion for exciting the MI is obtained. It is shown that the higher-order term can either suppress or enhance the MI, which is interesting for control of the system instability. Importantly, we predict that with the help of the higher-order nonlinearity, the MI can also take place in a BEC with repulsively contact interactions. The analytical results are confirmed by direct numerical simulations.
我们通过解析和数值方法研究了由具有高阶非线性的修正格罗斯 - 皮塔耶夫斯基（GP）方程描述的玻色 - 爱因斯坦凝聚体（BEC）的调制不稳定性（MI）。得到了一个激发MI的新的显式时间相关判据。结果表明，高阶项既可以抑制也可以增强MI，这对于控制系统不稳定性很有意义。重要的是，我们预测在高阶非线性的帮助下，MI也可以在具有排斥接触相互作用的BEC中发生。解析结果通过直接数值模拟得到了证实。
