Crossover from Fermi liquid to Wigner molecule behavior in quantum dots

TL;DR

This paper investigates how quantum dots transition from Fermi liquid to Wigner molecule behavior as electron correlations increase, using advanced Monte Carlo simulations to identify a universal crossover at a surprisingly small density parameter.

Contribution

It provides the first numerically exact analysis of the correlation-driven crossover in quantum dots, revealing a universal behavior governed by the density parameter r_s.

Findings

Crossover occurs at r_s ≈ 4

Data supports a Wigner molecule description for r_s > r_c

Fermi liquid behavior dominates for r_s < r_c

Abstract

The crossover from weak to strong correlations in parabolic quantum dots at zero magnetic field is studied by numerically exact path-integral Monte Carlo simulations for up to eight electrons. By the use of a multilevel blocking algorithm, the simulations are carried out free of the fermion sign problem. We obtain a universal crossover only governed by the density parameter $r_s$. For $r_s>r_c$, the data are consistent with a Wigner molecule description, while for $r_s<r_c$, Fermi liquid behavior is recovered. The crossover value $r_c \approx 4$ is surprisingly small.