Quantum Critical Point at Finite Doping in the 2D Hubbard Model: A Dynamical Cluster Quantum Monte Carlo Study

摘要

We explore the Matsubara quasiparticle fraction and the pseudogap of thetwo-dimensional Hubbard model with the dynamical cluster quantum Monte Carlomethod. The character of the quasiparticle fraction changes from non-Fermiliquid, to marginal Fermi liquid to Fermi liquid as a function of doping,indicating the presence of a quantum critical point separating non-Fermi liquidfrom Fermi liquid character. Marginal Fermi liquid character is found at lowtemperatures at a very narrow range of doping where the single-particle densityof states is also symmetric. At higher doping the character of thequasiparticle fraction is seen to cross over from Fermi Liquid to MarginalFermi liquid as the temperature increases.