Inertial active Ornstein-Uhlenbeck particle in the presence of magnetic field

TL;DR

This study investigates how inertia and magnetic fields influence the dynamics of an active Ornstein-Uhlenbeck particle in two dimensions, revealing that magnetic effects depend on medium viscosity and activity levels, with notable effects on displacement and correlations.

Contribution

It provides a combined numerical and analytical analysis of inertial active particles under magnetic fields, highlighting the role of inertia and activity in their steady-state behavior and displacement characteristics.

Findings

Inertia significantly affects particle dynamics in magnetic fields.

Magnetic field enhances displacement in confined particles but suppresses it in free particles.

At long times, particle behavior becomes independent of activity under strong magnetic fields.

Abstract

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 behaviour 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 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 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 correlation in the dynamics.