Escape dynamics in an anisotropically driven Brownian magneto-system

• Published in: Europhysics letters Vol. 139; no. 2; pp. 21003 - 21007
• Main Authors: Abdoli, I., Sommer, J.-U., Löwen, H., Sharma, A.
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences, IOP Publishing and Società Italiana di Fisica 01.07.2022; IOP Publishing
• Subjects: Brownian motion; Diffusion barriers; Diffusion coefficient; Diffusion rate; Dynamics; Lorentz force; Magnetic fields; Rescaling
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/0295-5075/ac7c31

Abstract Thermally activated escape of a Brownian particle over a potential barrier is well understood within Kramers theory. When subjected to an external magnetic field, the Lorentz force slows down the escape dynamics via a rescaling of the diffusion coefficient without affecting the exponential dependence on the barrier height. Here, we study the escape dynamics of a charged Brownian particle from a two-dimensional truncated harmonic potential under the influence of Lorentz force due to an external magnetic field. The particle is driven anisotropically by subjecting it to noises with different strengths along different spatial directions. We show that the escape time can largely be tuned by the anisotropic driving. While the escape process becomes anisotropic due to the two different noises, the spatial symmetry is restored in the limit of large magnetic fields. This is attributed to the Lorentz-force–induced coupling between the spatial degrees of freedom which makes the difference between two noises irrelevant at high magnetic fields. The theoretical predictions are verified by Brownian dynamics simulations. In principle, our predictions can be tested by experiments with a Brownian gyrator in the presence of a magnetic field.