Decoherence and Brownian motion of a polarizable particle near a surface

We analyze the classical and quantized center-of-mass motion of a polarizable particle interacting with the fluctuations of the electromagnetic (EM) field in the presence of a medium. As a polarizable particle is immersed in a thermal environment, the momentum impulses imparted by the field fluctuations lead to momentum diffusion and drag for the particle's classical center of mass. When considering the quantized center-of-mass motion of the particle, these very fluctuations gain information about its position, leading to decoherence in the position basis. We derive a position localization master equation for the particle's quantized center of mass, and examine its classical center-of-mass momentum diffusion, elucidating correspondences between classical and quantum Brownian motion of polarizable particles near media.