论文标题
引力圆游泳者的共振扩散
Resonant diffusion of a gravitactic circle swimmer
论文作者
论文摘要
我们研究了由于引力场的存在，因此研究了受外部扭矩的单手活动粒子的动力学。我们的计算机模拟显示，当外部扭矩接近内在的角漂移时，引力剂的长时间扩散率随意增加。我们根据噪声驱动的pendulum问题的特征和特征值提供了均方位移的分析表达式。然后，随着旋转扩散降低并接近潜在的经典分支，通过消失的fokker-planck方程的最低特征值的消失，在扩散率中明显的最大值被合理化。屏障主导运动的简单谐波振荡器图片为共振的发作提供了定量描述，而其有效性范围是由交叉对临界损失为主的策略确定的。
We investigate the dynamics of a single chiral active particle subject to an external torque due to the presence of a gravitational field. Our computer simulations reveal an arbitrarily strong increase of the long-time diffusivity of the gravitactic agent when the external torque approaches the intrinsic angular drift. We provide analytic expressions for the mean-square displacement in terms of eigenfunctions and eigenvalues of the noisy-driven-pendulum problem. The pronounced maximum in the diffusivity is then rationalized by the vanishing of the lowest eigenvalues of the Fokker-Planck equation for the angular motion as the rotational diffusion decreases and the underlying classical bifurcation is approached. A simple harmonic-oscillator picture for the barrier-dominated motion provides a quantitative description for the onset of the resonance while its range of validity is determined by the crossover to a critical-fluctuation-dominated regime.
