Reevaluation of radiation reaction and consequences for light-matter interactions at the nanoscale

TL;DR

This paper reevaluates radiation reaction effects in nanoscale light-matter interactions using a hydrodynamic approach, revealing damping-dependent source terms and nonlocal effects that influence electromagnetic responses.

Contribution

It introduces a novel hydrodynamic model based on radiation reaction for non-relativistic electrons, providing new insights into damping effects in nanoscale systems.

Findings

Damping coefficient may be proportional to local charge density

Identification of nonlocal contributions from magnetic field derivatives

Modified linear and nonlinear electromagnetic responses

Abstract

In the context of electromagnetism and nonlinear optical interactions damping is generally introduced as a phenomenological, viscous term that dissipates energy, proportional to the temporal derivative of the polarization. Here, we follow the radiation reaction method presented in [G. W. Ford and R. F. O'Connell, Phys. Lett. A, 157, 217 (1991)], which applies to non-relativistic electrons of finite size, to introduce an explicit reaction force in the Newtonian equation of motion, and derive a hydrodynamic equation that offers new insight on the influence of damping in generic plasmas, metal-based and/or dielectric structures. In these settings, we find new damping-dependent linear and nonlinear source terms that suggest the damping coefficient is proportional to the local charge density, and nonlocal contributions that stem from the spatial derivative of the magnetic field and discuss the conditions that could modify both linear and nonlinear electromagnetic responses.