International Journal of Modern Physics B
NUMERICAl STUDY OF THE 2D HUBBARD MODEL AT HALF FILLING
Sandro Sorella, Alberto Parola, Michele Parrinello, Erio Tosatti
Abstract
The ground state of the 2D (square lattice) finite-size Hubbard model is studied at half filling with a newly developed Quantum Monte Carlo method. We have studied square cells from 18 to 242 sites for U=3 with high statistical accuracy to perform a reliable size scaling analysis. The results confirm that the system is an antiferromagnetic insulator. The finite size scaling results are discussed in detail, focusing on the behaviour of magnetization, and most particularly of momentum distribution.