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- Bruun, Georg, et al.
(författare)
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Clock shifts in a Fermi gas interacting with a minority component: A soluble model
- 2010
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 81:3
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Tidskriftsartikel (refereegranskat)abstract
- We consider the absorption spectrum of a Fermi gas mixed with a minority species when majority fermions are transferred to another internal state by an external probe. In the limit when the minority species is much more massive than the majority one, we show that the minority species may be treated as static impurities and the problem can be solved in closed form. The analytical results bring out the importance of vertex corrections, which change qualitatively the nature of the absorption spectrum. It is demonstrated that large line shifts are not associated with resonant interactions in general. We also show that the commonly used ladder approximation fails when the majority component is degenerate for large mass ratios between the minority and majority species and that bubble diagrams, which correspond to the creation of many particle-hole pairs, must be taken into account. We carry out detailed numerical calculations, which confirm the analytical insights, and we point out the connection to shadowing phenomena in nuclear physics.
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| 6. |
- Zollner, Sascha, et al.
(författare)
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Bosonic and Fermionic Dipoles on a Ring
- 2011
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Ingår i: Physical Review Letters. - 1079-7114. ; 107:3
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Tidskriftsartikel (refereegranskat)abstract
- We show that dipolar bosons and fermions confined in a quasi-one-dimensional ring trap exhibit a rich variety of states because their interaction is inhomogeneous. For purely repulsive interactions, with increasing strength of the dipolar coupling there is a crossover from a gaslike state to an inhomogeneous crystal-like one. For small enough angles between the dipoles and the plane of the ring, there are regions with attractive interactions, and clustered states can form.
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