Caprini Lorenzo, Marini Bettolo Marconi Umberto
Scuola di Scienze e Tecnologie, Università di Camerino, Via Madonna delle Carceri, I-62032 Camerino, Italy.
J Chem Phys. 2021 Jan 14;154(2):024902. doi: 10.1063/5.0030940.
We study how inertia affects the behavior of self-propelled particles moving through a viscous solvent by employing the underdamped version of the active Ornstein-Uhlenbeck model. We consider both potential-free and harmonically confined underdamped active particles and investigate how the single-particle trajectories change as the drag coefficient is varied. In both cases, we obtain the matrix of correlations between the position, velocity, and self-propulsion and the explicit form of the steady-state probability distribution function. Our results reveal the existence of marked equal-time correlations between velocity and active force in the non-equilibrium steady state. Inertia also affects the time-dependent properties of the active particles and leads to non-monotonic decay of the two-time correlation functions of particle positions and velocities. We also study how the virial pressure of particles confined to harmonic traps changes as one goes from the overdamped to the underdamped regime. Finally, the study of the correlations in the underdamped regime is extended to the case of a chain of active particles interacting via harmonic springs.
我们通过采用欠阻尼版本的活性奥恩斯坦 - 乌伦贝克模型，研究惯性如何影响在粘性溶剂中运动的自驱动粒子的行为。我们考虑了无势和受谐约束的欠阻尼活性粒子，并研究了随着阻力系数的变化，单粒子轨迹如何改变。在这两种情况下，我们都得到了位置、速度和自推进之间的关联矩阵以及稳态概率分布函数的显式形式。我们的结果揭示了在非平衡稳态下速度和活性力之间存在显著的等时关联。惯性还影响活性粒子的时间相关性质，并导致粒子位置和速度的双时关联函数呈现非单调衰减。我们还研究了从过阻尼状态转变到欠阻尼状态时，限制在谐势阱中的粒子的维里压力如何变化。最后，对欠阻尼状态下关联的研究扩展到了通过谐弹簧相互作用的活性粒子链的情况。
