Ultracold atoms in one-dimensional optical lattices approaching the Tonks-Girardeau regime

TL;DR

This paper investigates the transition of ultracold bosonic gases in one-dimensional optical lattices from soft-core to Tonks-Girardeau regime, highlighting the conditions for reaching the fermion-like behavior.

Contribution

The study introduces a unified numerical framework to analyze the many-body physics of bosons transitioning from soft-core to hard-core regimes in 1D lattices.

Findings

Tonks-Girardeau regime achieved only at strong lattice potentials

Higher densities with Mott-like phases do not accelerate convergence to the hard-core limit

Short-range correlations in Mott-like phases do not enhance the fermionization process

Abstract

Recent experiments on ultracold atomic alkali gases in a one-dimensional optical lattice have demonstrated the transition from a gas of soft-core bosons to a Tonks-Girardeau gas in the hard-core limit, where one-dimensional bosons behave like fermions in many respects. We have studied the underlying many-body physics through numerical simulations which accommodate both the soft-core and hard-core limits in one single framework. We find that the Tonks-Girardeau gas is reached only at the strongest optical lattice potentials. Results for slightly higher densities, where the gas develops a Mott-like phase already at weaker optical lattice potentials, show that these Mott-like short range correlations do not enhance the convergence to the hard-core limit.