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Title
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Atypical BCS-BEC crossover induced by quantum-size effects
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Author
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Abstract
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| Quantum-size oscillations of the basic physical characteristics of a confined fermionic condensate are a well-known phenomenon. Its conventional understanding is based on the single-particle physics, whereby the oscillations follow variations in the single-particle density of states driven by the size quantization. Here we present a study of a cigar-shaped ultracold superfluid Fermi gas, which demonstrates an important many-body aspect of the quantum-size coherent effects, overlooked previously. The many-body physics is revealed here in the atypical crossover from the Bardeen-Cooper-Schrieffer (BCS) superfluid to the Bose-Einstein condensate (BEC) induced by the size quantization of the particle motion. The single-particle energy spectrum for the transverse dimensions is tightly bound, whereas for the longitudinal direction it resembles a quasi-free dispersion. This results in the formation of a series of single-particle subbands (shells) so that the aggregate fermionic condensate becomes a coherent mixture of subband condensates. Each time when the lower edge of a subband crosses the chemical potential, the BCS-BEC crossover is approached in this subband, and the aggregate condensate contains both BCS and BEC-like components. |
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Language
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English
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Source (journal)
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Physical review : A : atomic, molecular and optical physics. - Lancaster, Pa, 1990 - 2015
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Publication
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Lancaster, Pa
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2012
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ISSN
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1094-1622
[online]
1050-2947
[print]
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Volume/pages
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86
:3
(2012)
, 7 p.
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Article Reference
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033612
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ISI
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000308639500004
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (open access)
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