The Different Effect of Electron-Electron Interaction on the Spectrum of Atoms and Quantum Dots

TL;DR

This paper compares how electron-electron interactions affect the spectral properties of atoms and quantum dots, revealing distinct behaviors due to their different confining potentials and excitation energy dependencies.

Contribution

It provides a comparative analysis of electron-electron scattering rates in atoms and quantum dots, highlighting the different impacts on their spectral resolutions.

Findings

In alkali atoms, excitations do not acquire a width from electron-electron interactions.

In complex atoms, electron-electron interactions can cause broadening of excitations.

In quantum dots, electron-electron interactions significantly limit the number of resolvable excitations.

Abstract

The electron-electron scattering rate of single particle excitations in atoms is estimated and compared with the corresponding rate in quantum dots. It is found that in alkali atoms single particle excitations do not acquire a width due to electron-electron interaction, while in complex atoms they may. This width is typically smaller than the single particle level spacing, and hence does not affect the number of discrete single particle excitations resolved below the ionization threshold. This situation is contrasted with that of quantum dots where electron-electron interaction severely limits the number of resolved excitations. Unlike the case of quantum dots, the scattering rate in atoms is found to decrease with increasing excitation energy. The different effect of electron-electron interaction on the spectrum of quantum dots and atoms is traced to the different confining potentials in the two systems.