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Title
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Bipolarons and multipolarons consisting of impurity atoms in a Bose-Einstein condensate
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Author
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Abstract
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| The variational Feynman formalism for the polaron, extended to an all-coupling treatment of bipolarons, is applied for two impurity atoms in a Bose-Einstein condensate. This shows that if the polaronic coupling strength is large enough, the impurities will form a bound state (the bipolaron). As a function of the mutual repulsion between the impurities, two types of bipolaron are distinguished: a tightly bound bipolaron at weak repulsion and a dumbbell bipolaron at strong repulsion. Apart from the binding energy, the evolution of the bipolaron radius and its effective mass are also examined as a function of the strength of the repulsive interaction between the impurities and of the polaronic coupling strength. We then apply the strong-coupling formalism to multiple-impurity atoms in a condensate, which leads to the prediction of multipolaron formation in the strong-coupling regime. The results of the two formalisms are compared for two impurities in a condensate, which results in a general qualitative agreement and a quantitative agreement at strong coupling. Typically, the system of impurity atoms in a Bose-Einstein condensate is expected to exhibit the polaronic weak-coupling regime. However, the polaronic coupling strength is, in principle, tunable with a Feshbach resonance. |
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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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2013
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ISSN
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1094-1622
[online]
1050-2947
[print]
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DOI
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10.1103/PHYSREVA.88.013613
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Volume/pages
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88
:1
(2013)
, p. 1-12
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Article Reference
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013613
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ISI
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000321713200004
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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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