QED FOR A FIBRILLAR MEDIUM OF 2-LEVEL ATOMS

We consider a fibrillar medium with a continuous distribution of two-l evel atoms coupled to quantized electromagnetic fields. Perturbation t heory is developed based on the current algebra satisfied by the atomi c operators. The one-loop corrections to the dispersion relation for t he polaritons and the dielectric constant are computed. Renormalizatio n-group equations are derived that demonstrate a screening of the two- level splitting at higher energies. Our results are compared with know n results in the slowly varying envelope and rotating-wave approximati ons. We also discuss the quantum sine-Gordon theory as an approximate theory.