Spectral function of the Anderson model: A quantum Monte Carlo calculation

We have obtained the spectral function of the asymmetric Anderson model at low temperature through analytic continuation of quantum Monte Carlo data. While not quantitatively exact, the qualitative features of the spectral function clearly allow us to distinguish between the local-moment, mixed-valent, and empty-orbital regimes. We show how the spectral function changes as a function of particle-hole asymmetry and the Coulomb potential U