Fluorescence line shapes and cooperative spontaneous emission in disordered one-dimensional molecular aggregates are calculated using closed expressions derived by applying the method of optimal fluctuation. A simple scaling relation Ls ∼ ωs is established between the low temperature disorder-induced Stokes shift ωs and the superradiance enhancement factor Ls. Scaling of the Stokes shift with a...

Using the general expressions for level shifts obtained from the master equation for a small system interacting with a large one considered as a reservoir, we calculate the dispersive potentials between an atom and a wall in the dipole approximation. We analyze in detail the particular case of a two-level atom in the presence of a perfectly conducting wall. We study the van der Waals as well as...

The temperature dependence of static dielectric susceptibility of a strongly coupled dipolar system is calculated with self consistent mean fluctuation field approximation. Results are qualitatively in good agreement with, quantum paraelectric, SrTiO3 in the low temperature regime; and identify the system as a “gaped quantum paraelectric” near its quantum critical point. Quantum scaling along w...