arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2104.00609cond-mat.stat-mechcond-mat.soft
收藏

间歇调和势下的布朗运动

Brownian motion under intermittent harmonic potentials

Ion Santra, Santanu Das, Sujit Kumar Nath

摘要:

本文研究了强度为$μ= μ_0 ν$的间歇谐波势对具有阻尼系数$ν$的过阻尼布朗粒子的影响。这可以被认为是实现随机重置的现实模型。我们表明,这种动态承认一个固定的解决方案,在所有参数制度和计算的位置分布的全时变方差,并找到特征松弛时间。我们发现在极限下的精确的非平衡定态分布--(i)$γ\llμ_0 $,它显示出一个非平凡的分布,另外作为$μ_0\to\infty$,我们得到了具有不应期的复位的结果;(ii)$γ\ggμ_0$,其中粒子弛豫到具有原始势的一半强度的Ornstein-Uhlenbeck过程的Boltzmann分布;(iii)中间$γ=2nμ_0$,对于$n=1, 2$。找到目标的平均首次通过时间(MFPT)表现出与切换速率的优化,然而,与瞬时复位不同的是,MFPT不会发散,而是在大速率下达到稳定值。MFPT也表现出类似的行为相对于潜在的强度。我们的结果可以在胶体的实验中使用光镊验证。

英文摘要:

We study the effects of an intermittent harmonic potential of strength $μ= μ_0 ν$ -- that switches on and off stochastically at a constant rate $γ$, on an overdamped Brownian particle with damping coefficient $ν$. This can be thought of as a realistic model for realisation of stochastic resetting. We show that this dynamics admits a stationary solution in all parameter regimes and compute the full time dependent variance for the position distribution and find the characteristic relaxation time. We find the exact non-equilibrium stationary state distributions in the limits -- (i) $γ\llμ_0 $ which shows a non-trivial distribution, in addition as $μ_0\to\infty$, we get back the result for resetting with refractory period; (ii) $γ\ggμ_0$ where the particle relaxes to a Boltzmann distribution of an Ornstein-Uhlenbeck process with half the strength of the original potential and (iii) intermediate $γ=2nμ_0$ for $n=1, 2$. The mean first passage time (MFPT) to find a target exhibits an optimisation with the switching rate, however unlike instantaneous resetting the MFPT does not diverge but reaches a stationary value at large rates. MFPT also shows similar behavior with respect to the potential strength. Our results can be verified in experiments on colloids using optical tweezers.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑