Ordering in one-dimensional few-fermion clusters with repulsive interactions

• Published in: New journal of physics Vol. 18; no. 2; pp. 25015 - 25020
• Main Authors: Carbonell-Coronado, C, Soto, F De, Gordillo, M C
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 12-02-2016
• Subjects: Antiferromagnetism; Atomic properties; Clusters; Cold spinning; Computer simulation; confined systems; Contact potentials; Fermions; Ferromagnetism; few-body clusters; Physics; quantum Monte Carlo
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/18/2/025015

By using a diffusion Monte Carlo (DMC) technique, we studied the behaviour of a mixture of spin-up and spin-down cold fermionic atoms confined in one-dimensional harmonic potentials. We considered only small balanced clusters (up to eight atoms) or arrangements in which the difference between the population of fermions with different spins is one (with a maximum total number of nine). The atom-atom interactions were modeled by a contact repulsive potential. We focused on the ordering of the confined fermions, finding that the probability of having a pure antiferromagnetic arrangement of atoms decreases strongly with the number of fermions, as to be almost negligible for our largest clusters. Exactly the same can be said of a pure ferromagnetic state.