Quasi-One-Dimensional Few-Body Systems with Correlated Gaussians

TL;DR

This paper investigates ultracold few-body systems in a realistic 3D model with finite-range interactions, comparing results to idealized 1D models, and finds conditions under which the simpler models are accurate.

Contribution

It introduces a 3D correlated Gaussian approach to study few-body systems and assesses the validity of 1D idealized models across different interaction strengths and particle types.

Findings

Idealized 1D models are accurate for small to intermediate interactions at aspect ratios >4.

The idealized model remains valid for bosonic systems in the strong interaction limit.

For fermionic systems, the idealized model is not accurate even at large aspect ratios.

Abstract

The theoretical study of ultracold few-body systems is often done using an idealized 1D model with zero range interactions. Here we study these systems using a more realistic 3D model with finite range interactions. We place three-particles, two identical and one impurity, in an axial symmetric harmonic trap and solve the corresponding stationary Schr\"odinger equation using the correlated Gaussian method for different particle types, aspect ratios and interactions strength. We show that the idealized model is accurate for small and intermediate strength interactions at aspect ratios larger than four, independently of the particle types. In the strongly interacting limit, the idealized model is acceptable for bosonic systems, but not for fermionic systems even at large aspect ratios.