PHOTON CONVERSION AMONG MULTICHROMATIC WAVES IN 2-LEVEL ATOM SYSTEMS

In this paper, we shall discuss a generalized version of the Jaynes-Cu mmings model in which a two-level atom is coupled to multichromatic wa ves with general frequencies and coupling constants. We shall show tha t this two-level atom system can be mapped into an effective model in which a quantum particle moves in a lattice whose sites specify the nu mber of photons in the multichromatic waves. In general, when the numb er L of modes is greater than two, large energy exchanges among differ ent monochromatic waves are possible (L = 2 is a special case; exchang es of a large number of photons are possible only for degenerate modes ). Depending on the frequencies of the electromagnetic modes, we can c lassify the two-level systems in two categories. In one case, the eige nfunctions of the quantum particle are extended and thus exchange of a large number of photons is possible. In the other case, the eigenfunc tions of the quantum particle are localized and exchange of a large nu mber of photons is greatly suppressed.