Application of Cluster Perturbation Theory to Quantum Monte Carlo Data

We propose a new way to calculate the spectral func-tions of the Hubbard Hamiltonians by combining the clus-ter perturbation theory [Phys. Rev. Lett. 84, 522 (2000)] and the auxiliary eld quantum Monte Carlo simulations. Unlike the original cluster perturbation theory, our method can work for a large cluster size and at nite temperatures. Spectral functions of the one- and two-dimensional Hub-bard models are calculated as an illustration of our method.