QUANTUM MONTE CARLO SIMULATIONS OF THE TWO-DIMENSIONAL ATTRACTIVE HUBBARD MODEL: PHASE DIAGRAM AND SPECTRAL PROPERTIES

摘要

The problem of a crossover from a weak coupling BCS (Bardeen-Cooper-Schrieffer,) picture of Cooper pair formation and condensation at a critical temperature to a Bose-Einstein condensation (BEC,) of preformed (local) pairs has recently attracted great attention. The motivation to study Figure 1. "Crossover" from a BCS-like endpoint to a BEC endpoint along the superconducting phase transition line. δ symbolices the control parameter driving the crossover, which is in this diagram associated with the (inverse) coupling strength in case of the attractive Hubbard model and the electronic carrier doping in case of the cuprates.