Few strongly interacting ultracold fermions in one-dimensional traps of different shapes

TL;DR

This paper investigates how the shape of one-dimensional traps influences the ground-state properties and spatial separation of a few strongly interacting ultracold fermions with different masses, revealing shape-dependent phase transitions.

Contribution

It provides an exact diagonalization analysis of few-fermion systems showing shape-dependent spatial separation and a transition between different ordering states in varying trap geometries.

Findings

Different trap shapes lead to distinct density profiles in the strong interaction limit.

A specific transition between orderings occurs when changing the trap from a box to a harmonic oscillator.

Finite-size scaling reveals the nature of the transition in few-body systems.

Abstract

The ground-state properties of a few spin-1/2 fermions with different masses and interacting via short-range contact forces are studied within an exact diagonalization approach. It is shown that, depending on the shape of the external confinement, different scenarios of the spatial separation between components manifested by specific shapes of the density profiles can be obtained in the strong interaction limit. We find that the ground-state of the system undergoes a specific transition between orderings when the confinement is changed adiabatically from a uniform box to a harmonic oscillator shape. We study the properties of this transition in the framework of the finite-size scaling method adopted to few-body systems.