The Ground and Low Lying Excited States of the TwoDimensional Hubbard Model
Abstract
We have studied the ground state of the twodimensional (2D) Hubbard model by using a quantum monte method paying special attention to the shell structure effect on finite size clusters. Our calculations show there is a gap for spin excitations in the ground state and incommensurate peaks at $(\pi \pm \delta, \pi)$ and $(\pi, \pi \pm \delta)$ in the spin correlation function for a low lying excited state. In the ground state, the long range part of the dwave superconducting correlation function is enhanced and the momentum distribution function at the Fermi level $(\pi,0)$ is rounded. The gap in spin excitations and the momentum distribution function rounding is consistent with opening a dwave superconducting gap in the ground state.
 Publication:

arXiv eprints
 Pub Date:
 April 1999
 arXiv:
 arXiv:condmat/9904310
 Bibcode:
 1999cond.mat..4310A
 Keywords:

 Condensed Matter  Strongly Correlated Electrons;
 Condensed Matter  Superconductivity
 EPrint:
 RevTex3.0, 4 pages, 4 figures