Correlations in Ultracold Trapped Few-Boson Systems: Transition from Condensation to Fermionization

TL;DR

This paper investigates how correlations in few ultracold bosons in one-dimensional double-well traps evolve from condensation to fermionization, revealing the loss of coherence and changes in momentum distribution and correlations.

Contribution

It provides a detailed analysis of the transition from Bose condensation to fermionization, linking coherence loss to natural orbital occupations and correlation functions.

Findings

Loss of coherence in the one-body density matrix during transition

Emergence of long-range tails in the momentum spectrum

Changes in two-body correlation functions indicating fermionization

Abstract

We study the correlation properties of the ground states of few ultracold bosons, trapped in double wells of varying barrier height in one dimension. Extending previous results on the signature of the transition from a Bose-condensed state via fragmentation to the hard-core limit, we provide a deeper understanding of that transition by relating it to the loss of coherence in the one-body density matrix and to the emerging long-range tail in the momentum spectrum. These are accounted for in detail by discussing the natural orbitals and their occupations. Our discussion is complemented by an analysis of the two-body correlation function.