Interaction Effects in the Mesoscopic Regime: A Quantum Monte Carlo Study of Irregular Quantum Dots

TL;DR

This study uses Quantum Monte Carlo methods to analyze interaction effects in irregular quantum dots, revealing differences from density functional theory and challenging existing theoretical assumptions about large quantum dots.

Contribution

It provides a detailed Quantum Monte Carlo analysis of ground state properties in irregular quantum dots, highlighting limitations of local spin density approximation.

Findings

Reduced probability of high spin states compared to DFT

Larger even/odd energy alternation than DFT

Even/odd effect diminishes with more electrons, contrary to theory

Abstract

We address the issue of accurately treating interaction effects in the mesoscopic regime by investigating the ground state properties of isolated irregular quantum dots. Quantum Monte Carlo techniques are used to calculate the distributions of ground state spin and addition energy. We find a reduced probability of high spin and a somewhat larger even/odd alternation in the addition energy from quantum Monte Carlo than in local spin density functional theory. In both approaches, the even/odd effect gets smaller with increasing number of electrons, contrary to the theoretical understanding of large dots. We argue that the local spin density approximation over predicts the effects of interactions in quantum dots.