Sharp crossover from composite fermionization to phase separation in microscopic mixtures of ultracold bosons

Garcia-March, Miguel A.; Julia-Diaz, B.; Astrakharchik, G. E.; Busch, Thomas; Boronat, J.; Polls, A.

Sharp crossover from composite fermionization to phase separation in microscopic mixtures of ultracold bosons

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Published Version

Date

2013

Authors

Garcia-March, Miguel A.

Julia-Diaz, B.

Astrakharchik, G. E.

Busch, Thomas

Boronat, J.

Polls, A.

Publisher

American Physical Society

Published Version

10.1103/PhysRevA.88.063604

Abstract

We show that a two-component mixture of a few repulsively interacting ultracold atoms in a one-dimensional trap possesses very diverse quantum regimes and that the crossover between them can be induced by tuning the interactions in one of the species. Starting from the composite fermionization regime, in which the interactions between both components are large and neither gas is phase coherent, our results show that a phase-separated state can be reached by increasing the interaction in one of the species. In this regime, the weakly interacting component stays at the center of the trap and becomes almost fully phase coherent, while the strongly interacting one is expelled to the edges of the trap. The crossover is sharp, as can be witnessed in the system's energy and in the occupation of the lowest natural orbital of the weakly interacting species. We show that such a transition is a few-atom effect which disappears for a large population imbalance.

Keywords

Bose-einstein condensate , Tonks-girardeau gas , States , Atoms

Citation

Garcia-March, M. A., Juliá-Díaz, B., Astrakharchik, G. E., Busch, T., Boronat, J. and Polls, A. (2013) 'Sharp crossover from composite fermionization to phase separation in microscopic mixtures of ultracold bosons', Physical Review A, 88(6), 063604. (5pp). doi: 10.1103/PhysRevA.88.063604