Infinite-UAnderson Hamiltonian for Dilute Alloys

A Hamiltonian corresponding to the strictly infinite-$U$ limit of the Anderson Hamiltonian is considered. It is argued that this Hamiltonian retains enough complexity to describe magnetic and nonmagnetic impurities. The relationships with the Kondo Hamiltonian are discussed. A resolvent formula for the T-matrix elements, convenient for diagram expansions, is given. The characterization and the summation of the most divergent terms for the susceptibility and the spin-flip T-matrix element, in the magnetic and nonmagnetic regimes, are carried out and shown to be much simpler than for the Kondo Hamiltonian.