Strongly enhanced dynamics of a charged Rouse dimer by an external magnetic field

TL;DR

This paper extends the Rouse model to include magnetic field effects on a charged dimer, revealing significant enhancements in dynamics and novel behaviors like transient superballistic motion due to Lorentz-force coupling.

Contribution

The study introduces an analytically solvable model for a charged dimer under magnetic field, providing new insights into magneto-induced dynamics in overdamped systems.

Findings

Enormous enhancement of dimer center dynamics

Transient superballistic behavior observed

Magnetic field reduces mobility and rotational diffusion

Abstract

While the dynamics of dimers and polymer chains in a viscous solvent is well understood within the celebrated Rouse model, the effect of an external magnetic field on the dynamics of a charged chain is much less understood. Here we generalize the Rouse model for a charged dimer to include the effect of an external magnetic field. Our analytically solvable model allows a fundamental insight into the magneto-generated dynamics of the dimer in the overdamped limit as induced by the Lorentz-force. Surprisingly, for a dimer of oppositely charged particles, we find an enormous enhancement of the dynamics of the dimer center which exhibits even a transient superballistic behavior. This is highly unusual in an overdamped system for there is neither inertia nor any internal or external driving. We attribute this to a significant translation and rotation coupling due to the Lorentz force. We also find that magnetic field reduces the mobility of a dimer along its orientation and its effective rotational diffusion coefficient. In principle, our predictions can be tested by experiments with colloidal particles and complex plasmas.