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

TY - JOUR

T1 - Fermionization of two-component few-fermion systems in a one-dimensional harmonic trap

AU - J. Lindgren, E.

AU - Rotureau, J.

AU - Forssén, C.

AU - G. Volosniev, A.

AU - Zinner, Nikolaj Thomas

N1 - 12 pages, 6 figures

PY - 2014/6/3

Y1 - 2014/6/3

N2 - 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 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.

AB - 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 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.

KW - cond-mat.quant-gas

KW - nucl-th

KW - quant-ph

U2 - 10.1088/1367-2630/16/6/063003

DO - 10.1088/1367-2630/16/6/063003

M3 - Journal article

SN - 1367-2630

VL - 16

JO - New Journal of Physics

JF - New Journal of Physics

M1 - 063003

ER -