Quantum Monte Carlo simulations of many-body phenomena in a single-impurity Anderson model

Over a limited temperature range, we were able to simulate, with a quantum Monte Carlo method, the major many-body phenomena in a single-impurity Anderson model. These phenomena include local-moment formation, mixed-valence behavior, and the Kondo effect. For some choices of parameters we reached sufficiently low temperatures that our calculations of Tchi/sub d/ agreed with the universal Kondo-impurity susceptibility computed by the renormalization-group technique. We also calculated the correlations between the spin and charge at the impurity and those at the lattice sites. In these correlations we observed oscillations reminiscent of Ruderman-Kittel-Kasuya-Yosida and Friedel oscillations. We also discuss the possibility of extending our calculations to the two-impurity and lattice Anderson Hamiltonians