Strong-damping limit of quantum Brownian motion in a disordered environment.

Faria, Arthur M; Bonança, Marcus V S; Lutz, Eric · Phys Rev E · 2026

basic_science · Level V

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Abstract

We consider a microscopic model of an inhomogeneous environment where an arbitrary quantum system is locally coupled to a harmonic bath via a finite-range interaction. We show that in the overdamped regime the position distribution obeys a classical Kramers-Moyal equation that involves an infinite number of higher-order derivatives, implying that the finite bath correlation length leads to non-Gaussian Markovian noise. We analytically solve the equation for a harmonically bound particle and analyze its non-Gaussian diffusion as well as its steady-state properties.