Recent Numerical Results on the Two-Dimensional Hubbard Model
A new method for simulating strongly correlated fermionic systems has been applied to the study of the ground state properties of the 2D Hubbard model at various fillings. Comparison has been made with exact diagonalization in the 2×2, 3×3 and 4×4 lattices where very good agreement has been verified. Numerical results concerning a)magnetization, b)momentum distribution, c)charge, spin and pairing correlations have been obtained with this method for sizes up to 16×16 sites and several fillings. The 2D antiferromangetic order is destroyed by the presence of few holes and is very sensitive to the boundary conditions. The momentum distribution of the doped system does not have a clear Fermi surface. This is also supported by the exponential decay of the density matrix at large enough distances. Particular attention will be paid to the single hole properties and hole-hole correlations.