Dykman M. I., Golding B., McCann L. I., Smelyanskiy V. N., Luchinsky D. G., Mannella R., McClintock P. V. E.
Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824.
Chaos. 2001 Sep;11(3):587-594. doi: 10.1063/1.1380368.
We discuss activated escape from a metastable state of a system driven by a time-periodic force. We show that the escape probabilities can be changed very strongly even by a comparatively weak force. In a broad parameter range, the activation energy of escape depends linearly on the force amplitude. This dependence is described by the logarithmic susceptibility, which is analyzed theoretically and through analog and digital simulations. A closed-form explicit expression for the escape rate of an overdamped Brownian particle is presented and shown to be in quantitative agreement with the simulations. We also describe experiments on a Brownian particle optically trapped in a double-well potential. A suitable periodic modulation of the optical intensity breaks the spatio-temporal symmetry of an otherwise spatially symmetric system. This has allowed us to localize a particle in one of the symmetric wells. (c) 2001 American Institute of Physics.
我们讨论了由时间周期力驱动的系统从亚稳态的激活逃逸。我们表明，即使是相对较弱的力也能极大地改变逃逸概率。在很宽的参数范围内，逃逸的激活能线性依赖于力的振幅。这种依赖关系由对数磁化率来描述，我们通过理论分析以及模拟和数字仿真对其进行了研究。给出了过阻尼布朗粒子逃逸率的一个闭式显式表达式，并表明它与仿真结果在定量上一致。我们还描述了对光学捕获在双阱势中的布朗粒子进行的实验。对光强度进行适当的周期调制打破了原本空间对称系统的时空对称性。这使我们能够将粒子定位在其中一个对称阱中。（c）2001美国物理研究所。
