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arXiv · 1105.1314

Pairing, crystallization and string correlations of mass-imbalanced atomic mixtures in one-dimensional optical lattices

Tommaso Roscilde·Cristian Degli Esposti Boschi·Marcello Dalmonte
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Abstract

We numerically determine the very rich phase diagram of mass-imbalanced binary mixtures of hardcore bosons (or equivalently -- fermions, or hardcore-Bose/Fermi mixtures) loaded in one-dimensional optical lattices. Focusing on commensurate fillings away from half filling, we find a strong asymmetry between attractive and repulsive interactions. Attraction is found to always lead to pairing, associated with a spin gap, and to pair crystallization for very strong mass imbalance. In the repulsive case the two atomic components remain instead fully gapless over a large parameter range; only a very strong mass imbalance leads to the opening of a spin gap. The spin-gap phase is the precursor of a crystalline phase occurring for an even stronger mass imbalance. The fundamental asymmetry of the phase diagram is at odds with recent theoretical predictions, and can be tested directly via time-of-flight experiments on trapped cold atoms.

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Tommaso Roscilde, Cristian Degli Esposti Boschi, Marcello Dalmonte. 2011-05-06. Pairing, crystallization and string correlations of mass-imbalanced atomic mixtures in one-dimensional optical lattices. https://doi.org/10.1209/0295-5075%2F97%2F23002

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