Möller, Gunnar, Jolicoeur, Th, Regnault, N (2009) Pairing in ultracold Fermi gases in the lowest Landau level. Physical Review A, 79 (3). ISSN 1050-2947. E-ISSN 1094-1622. (doi:10.1103/PhysRevA.79.033609) (KAR id:55559)
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Official URL: http://dx.doi.org/10.1103/PhysRevA.79.033609 |
Abstract
We study a rapidly rotating gas of unpolarized spin-1/2 ultracold fermions in the two-dimensional regime when all atoms reside in the lowest Landau level. Due to the presence of the spin degree of freedom both s-wave and p-wave interactions are allowed at ultralow temperatures. We investigate the phase diagram of this system as a function of the filling factor in the lowest Landau level and in terms of the ratio between s- and p-wave interaction strengths. We show that the presence of attractive interactions induces a wide regime of phase separation with formation of maximally compact droplets that are either fully polarized or composed of spin-singlets. In the regime with no phase separation, we give evidence for fractional quantum Hall states. Most notably, we find two distinct singlet states at the filling nu=2/3 for different interactions. One of these states is accounted for by the composite fermion theory, while the other one is a paired state for which we identify two competing descriptions with different topological structures. This paired state may be an Abelian liquid of composite spin-singlet Bose molecules with Laughlin correlations. Alternatively, it may be a known non-Abelian paired state, indicated by good overlaps with the corresponding trial wave function. By fine tuning of the scattering lengths it is possible to create the non-Abelian critical Haldane-Rezayi state for nu = 1/2 and the permanent state of Moore and Read for nu=1. For purely repulsive interactions, we also find evidence for a gapped Halperin state at nu=2/5.
Item Type: | Article |
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DOI/Identification number: | 10.1103/PhysRevA.79.033609 |
Uncontrolled keywords: | Physics of Quantum Materials |
Subjects: | Q Science > QC Physics > QC173.45 Condensed Matter |
Divisions: | Divisions > Division of Natural Sciences > Physics and Astronomy |
Depositing User: | Gunnar Moeller |
Date Deposited: | 05 Dec 2017 14:47 UTC |
Last Modified: | 16 Nov 2021 10:23 UTC |
Resource URI: | https://kar.kent.ac.uk/id/eprint/55559 (The current URI for this page, for reference purposes) |
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