Artuso Roberto, Rebuzzini Laura
Center for Nonlinear and Complex Systems, Università dell'Insubria a Como, Via Valleggio 11, 22100 Como, Italy.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Sep;68(3 Pt 2):036221. doi: 10.1103/PhysRevE.68.036221. Epub 2003 Sep 30.
We perform a numerical analysis of the effects of a nonlinear perturbation on the quantum dynamics of two models describing noninteracting cold atoms in a standing wave of light with a periodical modulated amplitude A(t). One model is the driven pendulum, recently considered by D.A. Steck, W.H. Oskay, and M.G. Raizen [Science 293, 274 (2001)], and the other is a variant of the well-known kicked rotator model. In absence of the nonlinear perturbation, the system is invariant under some discrete symmetries and quantum dynamical tunneling between symmetric classical islands is found. The presence of nonlinearity destroys tunneling, breaking the symmetries of the system. Finally, further consequences of nonlinearity in the kicked rotator case are considered.
我们对两个描述非相互作用冷原子在振幅呈周期性调制A(t)的驻波光中的模型的量子动力学进行了非线性微扰效应的数值分析。一个模型是驱动摆，最近由D.A. 斯特克、W.H. 奥斯卡伊和M.G. 赖曾 [《科学》293, 274 (2001)] 进行了研究，另一个是著名的受踢转子模型的变体。在不存在非线性微扰的情况下，系统在某些离散对称性下是不变的，并且发现了对称经典岛之间的量子动力学隧穿。非线性的存在破坏了隧穿，打破了系统的对称性。最后，考虑了受踢转子情形下非线性的进一步影响。
