Dephasing in Rydberg Facilitation Due to State-Dependent Dipole Forces

Rydberg atoms allow for the experimental study of open many-body systems and nonequilibrium phenomena. High dephasing rates are a generic feature of these systems, and therefore they can often be described by rate equations, i.e. in the classical limit. In this work, we analyze one potential origin of the decoherence in Rydberg atoms: dipole-force induced dephasing. As the wave function of the Rydberg (spin-up) state is repelled in the presence of another nearby Rydberg atom, while the ground (spin-down) state diffuses in place, the Franck-Condon overlap between the two spin components quickly decays causing a decoherence of the spin transition. With an analytic approach we obtain a simple expression for the dephasing rate of the Rydberg state depending on atomic and laser parameters, which agrees with numerical findings.