We compute the dynamical charge susceptibility in the two-dimensional Hubbard model within the dynamical cluster approximation. In order to understand the connection between charge susceptibility and pseudogap, we investigate the momentum, doping, and temperature dependence. We find that as a function of frequency, the dynamical charge susceptibility is well represented by a single peak at a characteristic frequency. It shows little momentum or temperature dependence, while the doping dependence is more evident, and no clear signature of the pseudogap is observed. Data for the doping evolution of the static susceptibility and for fluctuation diagnostics are presented. Our susceptibilities should be directly measurable in future Momentum-resolved electron energy-loss spectroscopy experiments.We compute the dynamical charge susceptibility in the two-dimensional Hubbard model within the dynamical cluster approximation. In order to understand the connection between charge susceptibility and pseudogap, we investigate the momentum, doping, and temperature dependence. We find that as a function of frequency, the dynamical charge susceptibility is well represented by a single peak at a characteristic frequency. It shows little momentum or temperature dependence, while the doping dependence is more evident, and no clear signature of the pseudogap is observed. Data for the doping evolution of the static susceptibility and for fluctuation diagnostics are presented. Our susceptibilities should be directly measurable in future Momentum-resolved electron energy-loss spectroscopy experiments.

arXiv:1908.04776Physical review. B./Physical review. BDec 5, 201922 citations

Effects of weak random disorder in the one-dimensional Hubbard model

Anders W. Sandvik, Douglas J. Scalapino

We introduce the notion of an impurity susceptibility as a measure of the effect of disorder on the properties of interacting many-particle systems. If finite, the impurity susceptibility gives the lowest-order correction to a given physical observable in the presence of disorder. If divergent, it signals that arbitrarily weak disorder leads to a qualitatively different physical behavior. Using a quantum Monte Carlo technique, impurity susceptibilities for various properties of the one-dimensional Hubbard model are calculated. Two types of disorder are considered; random hopping matrix elements and random potentials. For the local magnetic moment and the kinetic energy the impurity susceptibilities are finite. The impurity susceptibility of the q=2 ${\mathit{k}}_{\mathit{F}}$ spin response is divergent for both types of disorder, indicating a quenching of the T\ensuremath{\rightarrow}0 divergence of this quantity. The susceptibility of the q=0 spin response to random hopping diverges at half filling, as a consequence of a divergent magnetic susceptibility in the presence of this type of disorder. We also find large, possibly divergent, impurity susceptibilities for the q=2 ${\mathit{k}}_{\mathit{F}}$ and 4 ${\mathit{k}}_{\mathit{F}}$ charge-density responses.We introduce the notion of an impurity susceptibility as a measure of the effect of disorder on the properties of interacting many-particle systems. If finite, the impurity susceptibility gives the lowest-order correction to a given physical observable in the presence of disorder. If divergent, it signals that arbitrarily weak disorder leads to a qualitatively different physical behavior. Using a quantum Monte Carlo technique, impurity susceptibilities for various properties of the one-dimensional Hubbard model are calculated. Two types of disorder are considered; random hopping matrix elements and random potentials. For the local magnetic moment and the kinetic energy the impurity susceptibilities are finite. The impurity susceptibility of the q=2${\mathit{k}}_{\mathit{F}}$ spin response is divergent for both types of disorder, indicating a quenching of the T\ensuremath{\rightarrow}0 divergence of this quantity. The susceptibility of the q=0 spin response to random hopping diverges at half filling, as a consequence of a divergent magnetic susceptibility in the presence of this type of disorder. We also find large, possibly divergent, impurity susceptibilities for the q=2${\mathit{k}}_{\mathit{F}}$ and 4${\mathit{k}}_{\mathit{F}}$ charge-density responses.

Physical review. B, Condensed matterApr 15, 199311 citations

Numerical simulations of the two-dimensional Hubbard model: Dynamic properties

Douglas J. Scalapino

Physica C SuperconductivityDec 1, 199115 citations

{\mathit{k}}_{\mathit{F}}

spin response is divergent for both types of disorder, indicating a quenching of the T\ensuremath{\rightarrow}0 divergence of this quantity. The susceptibility of the q=0 spin response to random hopping diverges at half filling, as a consequence of a divergent magnetic susceptibility in the presence of this type of disorder. We also find large, possibly divergent, impurity susceptibilities for the q=2

{\mathit{k}}_{\mathit{F}}

and 4

{\mathit{k}}_{\mathit{F}}

charge-density responses.