Exact electrodynamics versus standard optics for a slab of cold dense gas

摘要: We study light propagation through a slab of cold gas using both the standard electrodynamics polarizable media, and massive atom-by-atom simulations electrodynamics. The main finding is that predictions from two methods may differ qualitatively when density atomic sample $ wavenumber resonant $k$ satisfy $rho k^-3gtrsim 1$. reason mean-field theory, whereas for sufficiently strong light-mediated dipole-dipole interactions becomes correlated. deviations theory appear to scale with parameter k^-3$, we demonstrate noticeable effects already at k^-3 simeq 10^-2$. In dilute gases in an added inhomogeneous broadening show shifts resonance lines qualitative agreement predicted Lorentz-Lorenz shift "cooperative Lamb shift", but quantitative unsatisfactory. Our interpretation microscopic basis local-field corrections not fully understood.