Oscillations and negative velocity autocorrelation emerging from a Brownian particle model with hydrodynamic interactions.
Oscillations and negative velocity autocorrelation emerging from a Brownian particle model with hydrodynamic interactions.
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具有流体动力相互作用的布朗粒子模型出现振荡和负速度自相关。
DOI：
10.1103/physreve.101.052140
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
G. Paissan
中科院分区：
文献类型：
--
作者：
A. Viñales;M. Camuyrano;G. Paissan
从具有摩擦指数记忆核和流体动力相互作用的广义朗之万方程出发，研究了流体中粒子的动力学行为。通过拉普拉斯分析，得到了质点速度自相关函数（VACF）和均方位移（MSD）的解析表达式。我们的研究结果表明，在严格渐近的时间限制，粒子的动力学对应于一个粒子统治的GLE与狄拉克δ摩擦记忆内核和流体动力学相互作用。然而，在中间时间的动力学行为是定性的不同，由于存在的摩擦指数记忆内核的特征时间。值得注意的是，VACF表现出振荡和负相关制度，这让人想起已经观察到的功能，在分子动力学模拟的开创性工作。此外，MSD的涟漪似乎是与上述制度相关的新兴行为。
We study the dynamics of a particle in a fluid from a generalized Langevin equation (GLE) with a frictional exponential memory kernel and hydrodynamic interactions. By using Laplace analysis we obtain the analytical expressions for the velocity autocorrelation function (VACF) and mean square displacement (MSD) of the particle. Our results show that, in the strictly asymptotic time limit, the dynamics of the particle correspond to a particle ruled by a GLE with a Dirac delta friction memory kernel and hydrodynamic interactions. However, at intermediate times the dynamical behavior is qualitatively different due to the presence of a characteristic time in the frictional exponential memory kernel. Remarkably, the VACF exhibits oscillations and negative correlation regimes which are reminiscent of features already observed in pioneering works of molecular dynamics simulations. Moreover, ripples in the MSD appear as an emerging behavior associated with the mentioned regimes.