Two-dimensional Superfluidity and Localization in the Hard-Core Boson Model: a Quantum Monte Carlo Study

TL;DR

This study uses Quantum Monte Carlo simulations to explore superfluidity and localization in a two-dimensional hard-core boson model, revealing how disorder and particle density influence phase transitions and relate to high-temperature superconductor experiments.

Contribution

It provides new insights into the effects of disorder and density on superfluidity and localization in 2D bosonic systems using advanced simulation techniques.

Findings

Half-filled clean system exhibits a Kosterlitz-Thouless transition to superfluidity.

Superfluid density varies symmetrically and parabolically around half filling.

Disorder induces localization, creating distinct localized states depending on particle density.

Abstract

Quantum Monte Carlo simulations are used to investigate the two-dimensional superfluid properties of the hard-core boson model, which show a strong dependence on particle density and disorder. We obtain further evidence that a half-filled clean system becomes superfluid via a finite temperature Kosterlitz-Thouless transition. The relationship between low temperature superfluid density and particle density is symmetric and appears parabolic about the half filling point. Disorder appears to break the superfluid phase up into two distinct localized states, depending on the particle density. We find that these results strongly correlate with the results of several experiments on high-$T_c$ superconductors.