Abnormal superfluid fraction and structural properties of electrons in 2D and 3D quantum dots: an ab initio path-integral Monte Carlo study

TL;DR

This study uses ab initio path-integral Monte Carlo simulations to explore the unusual negative superfluid fraction and structural properties of electrons in 2D and 3D quantum dots, revealing unexpected independence between structure and superfluidity.

Contribution

It provides new direct Monte Carlo results showing the occurrence of negative superfluid fractions and their relation to structural properties in quantum dots, a novel insight in the field.

Findings

Identification of negative superfluid fraction under certain conditions.

No correlation between spatial structure and superfluidity.

Structural similarity for Fermi- and Bose-statistics despite divergent superfluid fractions.

Abstract

We present extensive new direct path-integral Monte Carlo results for electrons in quantum dots in two and three dimensions. This allows us to investigate the nonclassical rotational inertia (NCRI) of the system, and we find an abnormal negative superfluid fraction [Phys. Rev. Lett. 112, 235301 (2014)] under some conditions. In addition, we study the structural properties by computing a sophisticated center-two particle correlation function. Remarkably, we find no connection between the spatial structure and the NCRI, since the former can be nearly identical for Fermi- and Bose-statistics for parameters where the superfluid fraction is diverging towards negative infinity.