Shifts of a resonance line in a dense atomic sample

TL;DR

This paper investigates how dense atomic samples respond to light, revealing that inhomogeneous broadening restores typical mean-field effects like Lorentz-Lorenz shifts, while homogeneous samples do not exhibit these shifts.

Contribution

The study demonstrates that inhomogeneous broadening is essential for observing mean-field collective effects in dense atomic samples, using classical-electrodynamics simulations.

Findings

Homogeneous broadening shows no Lorentz-Lorenz shift.

Inhomogeneous broadening restores mean-field phenomena.

Collective effects depend on broadening mechanisms.

Abstract

We study the collective response of a dense atomic sample to light essentially exactly using classical-electrodynamics simulations. In a homogeneously broadened atomic sample there is no overt Lorentz-Lorenz local field shift of the resonance, nor a collective Lamb shift. However, addition of inhomogeneous broadening restores the usual mean-field phenomenology.