We study the simplest nontrivial model that describes a basic feature of strongly correlated systems, namely, the transfer of spectral weight between high- and low-energy excitations. We use the limit of infinite dimensions to calculate exactly the corresponding single-particle and optical-conductivity spectra. We comment on the relevance of these results to a recently proposed scenario for the breakdown of Fermi-liquid theory in strongly correlated metals.

• Received 30 January 1992

DOI:https://doi.org/10.1103/PhysRevB.46.7427