The effect of electron-electron interactions on the average polarizability of a mesoscopic system

TL;DR

This paper compares analytical and numerical methods to study how electron-electron interactions affect the polarizability of mesoscopic systems, revealing deviations at stronger interactions due to correlation effects.

Contribution

It provides a detailed comparison between analytical RPA calculations and exact numerical results for interacting mesoscopic systems, highlighting the impact of correlations.

Findings

Analytical RPA fits numerical results for weak interactions

Deviations occur at stronger interactions due to correlations

Correlations suppress polarizability below classical predictions

Abstract

A comparison between an analytical calculation of the polarizability of a mesoscopic interacting system in the random phase approximation and numerical exact diagonalization results is presented. While for weak interactions the analytical calculation fits the numerical results rather well, deviations appear for stronger interactions. This is the result of the appearance of intermediate range correlations in the electron density, which suppresses the polarizability below its classical value. The relevance to quantum dot systems is discussed.