Abstract:
We propose a numerically exact scheme to calculate spectral and magnetic properties of correlated systems. The scheme employs the weak-coupling determinantal continuous time quantum Monte Carlo method for the solution of the quantum impurity problem. This approach can treat multiorbital impurity models including Coulomb interaction of the most general form. The realistic five-band model for transition metal atom d-shells with full Coulomb interaction vertex as a Kondo impurity in a metal matrix has been calculated. We show a possibility to calculate magnetic susceptibilities of a single-spin Kondo impurity model with coupling to different environments: an ultrasmall grain, the Anderson model, corresponding to a lattice with random on-site energy levels, and a twodimensional lattice, where the density of states has a van Hove singularity. In order to calculate properties of correlated solid, a real correlated solid, namely strontium ruthenate Sr2RuO4, the continuous time quantum Monte Carlo method is used as an impurity solver within the dynamical mean-field theory.