Pairing of few Fermi atoms in one dimension

TL;DR

This paper investigates pairing phenomena in a few-fermion one-dimensional system with attractive interactions, revealing BCS-like pairing and dimer arrangements influenced by Pauli blockade through exact numerical methods.

Contribution

It provides the first detailed numerical analysis of few-fermion pairing and dimer arrangements in 1D traps, highlighting effects of interaction strength and finite particle number.

Findings

Evidence of BCS-like pairing in few-atom systems

Reproduction of even-odd oscillations in separation energy

Dimer arrangements affected by Pauli blockade in strong interactions

Abstract

We study a few Fermi atoms interacting through attractive contact forces in a one-dimensional trap by means of numerical exact diagonalization. From the combined analysis of energies and wave functions of correlated ground and excited states we find evidence of BCS-like pairing even for very few atoms. For moderate interaction strength, we reproduce the even-odd oscillation of the separation energy observed in [G. Zuern, A. N. Wenz, S. Murmann, A. Bergschneider, T. Lompe, and S. Jochim, Phys. Rev. Lett. 111, 175302 (2013)]. For strong interatomic attraction the arrangement of dimers in the trap differs from the homogeneous case as a consequence of Pauli blockade in real space.