Fermionization of two-component few-fermion systems in a one-dimensional harmonic trap

E J Lindgren,A G Volosniev,N T Zinner,C Forssén,J Rotureau

doi:10.1088/1367-2630/16/6/063003

E J Lindgren, A G Volosniev + Show 3 more

Open Access

https://doi.org/10.1088/1367-2630/16/6/063003

Copy DOI

Abstract

The nature of strongly interacting Fermi gases and magnetism is one of the most important and studied topics in condensed-matter physics. Still, there are many open questions. A central issue is under what circumstances strong short-range repulsive interactions are enough to drive magnetic correlations. Recent progress in the field of cold atomic gases allows one to address this question in very clean systems where both particle numbers, interactions and dimensionality can be tuned. Here we study fermionic few-body systems in a one dimensional harmonic trap using a new rapidly converging effective-interaction technique, plus a novel analytical approach. This allows us to calculate the properties of a single spin-down atom interacting with a number of spin-up particles, a case of much recent experimental interest. Our findings indicate that, in the strongly interacting limit, spin-up and spin-down particles want to separate in the trap, which we interpret as a microscopic precursor of one-dimensional ferromagnetism in imbalanced systems. Our predictions are directly addressable in current experiments on ultracold atomic few-body systems.

Highlights

Few-fermion systems are the building blocks of matter
Our predictions are directly addressable in current experiments on ultracold atomic few-body systems
An exciting recent development in atomic physics is the experimental realization of few-body Fermi systems with ultracold atoms [1, 2]

Summary

Introduction

Few-fermion systems are the building blocks of matter. Atoms and nuclei are well-known examples, and systems such as quantum dots, superconducting grains, and other nanoscale structures are of great interest. We study fermionic few-body systems in a one dimensional harmonic trap using a new rapidly converging effective-interaction technique, plus a novel analytical approach. While the two-body system in a harmonic trap has a well-known exact solution for any interaction strength, known as the Busch model [29], two-component fermionic few-body systems with more than two particles have not been solved exactly.

Results

Conclusion