Quantum dot ground state energies and spin polarizations: soft versus hard chaos

TL;DR

This paper investigates how the degree of chaos in ballistic quantum dots influences their ground state energies and spin polarizations, revealing increased fluctuations as chaos decreases.

Contribution

It introduces a model linking the dynamics from integrable to chaotic and shows how residual Coulomb interactions affect ground state properties.

Findings

Fluctuations in ground state energies increase with less chaos.

Spin polarization fluctuations are highly sensitive to the system's chaotic nature.

Residual Coulomb interactions play a significant role in mesoscopic fluctuations.

Abstract

We consider how the nature of the dynamics affects ground state properties of ballistic quantum dots. We find that ``mesoscopic Stoner fluctuations'', that arise from the residual screened Coulomb interaction, are very sensitive to the degree of chaos. It leads to ground state energies and spin-polarizations whose fluctuations strongly increase as a system becomes less chaotic. The crucial features are illustrated with a model that depends on a parameter that tunes the dynamics from nearly integrable to mostly chaotic.