This paper reports on the analysis of a spatially extended collection of two-level systems inside a cavity filled with electromagnetic radiation. A new feature of the analysis is the consideration of different strengths of coupling between different atoms and the field (due to the variation of the field intensity inside the cavity). The results are qualitatively different from those obtained under the assumption of equal coupling for all atoms.

• Received 3 October 1977

DOI:https://doi.org/10.1103/PhysRevLett.40.544