Pseudogaps and Their Interplay with Magnetic Excitations in the Doped 2D 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 $A(\overrightarrow{k},\omega )$ qualitatively reproduces both the momentum ( $d_{x^2{-y}^2}$ symmetry) and doping dependence of the pseudogap as found in photoemission experiments. The drastic doping dependence of the spin response ${\chi }_s(\overrightarrow{q},\omega )$, which is sharp in both $\overrightarrow{q}\left[\approx \right(\pi ,\pi \left)\right]$ and $\omega$ in the underdoped regime but broad and structureless otherwise, identifies remnants of the antiferromagnetic order as the driving mechanism behind the pseudogap and its evolution with doping.