Publication
Title
Bipolarons and multipolarons consisting of impurity atoms in a Bose-Einstein condensate
Author
Abstract
 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.
Language
English
Source (journal)
Physical review : A : atomic, molecular and optical physics. - Lancaster, Pa, 1990 - 2015
Publication
Lancaster, Pa : 2013
ISSN
1094-1622 [online]
1050-2947 [print]
Volume/pages
88:1(2013), p. 1-12
Article Reference
013613
ISI
000321713200004
Medium
E-only publicatie
Full text (Publishers DOI)
Full text (open access)
UAntwerpen
 Faculty/Department Research group Publication type Subject Affiliation Publications with a UAntwerp address