# Dynamical Charge Susceptibility in the Hubbard Model

## TL;DR

This paper calculates the dynamical charge susceptibility in the 2D Hubbard model using dynamical cluster approximation, revealing doping dependence and potential for experimental measurement, but finds no clear pseudogap signature.

## Contribution

It provides a detailed analysis of charge susceptibility's frequency, doping, and temperature dependence in the Hubbard model, connecting theoretical predictions with experimental observables.

## Key findings

- Susceptibility has a single peak at a characteristic frequency.
- Little dependence on momentum or temperature.
- Doping influences the static susceptibility significantly.

## Abstract

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.