Muhsin M, Sahoo M
Department of Physics, University of Kerala, Kariavattom, Thiruvananthapuram 695581, India.
Phys Rev E. 2022 Jul;106(1-1):014605. doi: 10.1103/PhysRevE.106.014605.
We consider an inertial active Ornstein-Uhlenbeck particle in an athermal bath. The particle is charged, constrained to move in a two-dimensional harmonic trap, and a magnetic field is applied perpendicular to the plane of motion. The steady-state correlations and the mean-square displacement are studied when the particle is confined as well as when it is set free from the trap. With the help of both numerical simulation and analytical calculations, we observe that inertia plays a crucial role in the dynamics in the presence of a magnetic field. In a highly viscous medium where the inertial effects are negligible, the magnetic field has no influence on the correlated behavior of position as well as velocity. In the time asymptotic limit, the overall displacement of the confined harmonic particle gets enhanced by the presence of a magnetic field and saturates for a stronger magnetic field. On the other hand, when the particle is set free, the overall displacement gets suppressed and approaches zero when the strength of the field is very high. Interestingly, it is seen that in the time asymptotic limit, the confined harmonic particle behaves like a passive particle and becomes independent of the activity, especially in the presence of a very strong magnetic field. Similarly, for a free particle the mean-square displacement in the long time limit becomes independent of activity even for a longer persistence of noise cor- relation in the dynamics.
我们考虑一个处于无热浴中的惯性活性奥恩斯坦 - 乌伦贝克粒子。该粒子带电，被限制在二维谐振子势阱中运动，并且施加了一个垂直于运动平面的磁场。研究了粒子被限制在势阱中以及从势阱中释放时的稳态关联和均方位移。借助数值模拟和解析计算，我们观察到在存在磁场的情况下，惯性在动力学中起着关键作用。在惯性效应可忽略不计的高粘性介质中，磁场对位置和速度的关联行为没有影响。在时间渐近极限下，受限谐振子粒子的总位移会因磁场的存在而增强，并在磁场更强时达到饱和。另一方面，当粒子被释放时，总位移会受到抑制，并且在磁场强度非常高时趋近于零。有趣的是，可以看到在时间渐近极限下，受限谐振子粒子的行为类似于被动粒子，并且变得与活性无关，特别是在存在非常强的磁场时。同样，对于自由粒子，即使在动力学中噪声关联的持续时间更长，长时间极限下的均方位移也变得与活性无关。
