1304.2992 (E. J. Lindgren et al.)

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

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

We study two-component fermionic few-body systems in a one dimensional harmonic trap. Different component fermions interact via a short-range interaction of arbitrary strength. Using a new effective interaction technique we solve in particular the simplest imbalanced case of two spin-up and one spin-down fermion (2+1) and study its properties. In the so-called fermionized limit of infinitely strong repulsive interactions, we solve the problem analytically and find close agreement with the numerical results. Our findings indicate that the spin-up and spin-down fermions tend to phase separate in the trap, which we interpret as a microscopic precursor of ferromagnetism. We confirm this conclusion by performing calculations for (3+1) and (6+1) systems for strong repulsive interactions. Our predictions are directly addressable in current experiments on ultracold atomic few-body systems.

View original: http://arxiv.org/abs/1304.2992