PSEUDOGAPS AND THEIR INTERPLAY WITH MAGNETIC EXCITATIONS IN THE DOPED2D HUBBARD-MODEL

On the basis of quantum Monte Carlo simulations of the two-dimensional Hubbard model which cover the doping range from the underdoped to the overdoped regime, we find that the single-particle spectral weight A( (k) over right arrow, omega) qualitatively reproduces both the momentu m (d(x2-y2) symmetry) and doping dependence of the pseudogap as found in photoemission experiments. The drastic doping dependence of the spi n response chi(s)((q) over right arrow, omega) which is sharp in both (q) over right arrow [approximate to (pi, pi)] and omega in the underd oped regime but broad and structureless otherwise, identifies remnants of the antiferromagnetic order as the driving mechanism behind the ps eudogap and its evolution with doping.