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Signatures of superfluidity in atomic Fermi gases

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Rodríquez Pinilla, Mirta
dc.date.accessioned 2012-02-10T09:04:15Z
dc.date.available 2012-02-10T09:04:15Z
dc.date.issued 2003-11-14
dc.identifier.isbn 951-22-6854-X
dc.identifier.issn 1455-0474
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/2129
dc.description.abstract After the experimental realization of Bose-Einstein condensation in dilute gases of alkali atoms, experimentalists started to trap the fermionic isotopes. The degenerate state for fermions was reported in 1999. The main objective of these experiments is to obtain superfluidity of fermionic gases. When there are attractive interactions between the fermions, the Fermi sea becomes unstable with respect to the formation of atomic Cooper pairs and the system becomes a superfluid. It turns out that the existing experimental cooling techniques allow minimum temperatures for fermions of the order of the Fermi temperature. Using Feshbach resonances induced by magnetic fields enhances the effective interactions between the atoms leading to superfluid transition temperatures of the order of the Fermi energy. This is a completely new regime of fermionic superfluidity far from the BCS superconductors, 3He and even high-Tc superconductors. The achievement of superfluidity on gases of fermionic alkalis is currently being pursued in many experimental groups. In this thesis, different signatures of the superfluid transition have been considered. The use of almost on-resonant laser light for coupling between the different internal states of the atoms as a method for probing superfluidity has been analyzed. Coupling between the paired states has been proposed as a way to directly detect the Cooper pair size. The Josephson effect, related to the phases of two coupled superfluids, is shown to present an asymmetry when the internal states of the atoms forming the pairs are coupled with different detunings. Vortices, intimately related to superfluidity, have also been considered. The single vortex solution of the Ginzburg-Landau equation for the superfluid order parameter has been numerically computed and a new vortex core size reflecting the trapping geometry has been obtained. Bloch oscillations have been analyzed for fermionic atoms both in the degenerate regime and in the superfluid regime. Superfluidity is found to supress the amplitude of the Bloch oscillations. en
dc.format.extent 72, [47]
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Helsinki University of Technology en
dc.publisher Teknillinen korkeakoulu fi
dc.relation.ispartofseries Helsinki University of Technology Laboratory of Computational Engineering publications. Report B en
dc.relation.ispartofseries 34 en
dc.relation.haspart Bruun G. M., Törmä P., Rodríguez M. and Zoller P., 2001. Laser probing of Cooper-paired trapped atoms. Physical Review A 64, pages 033609 : 1-10. [article1.pdf] © 2001 American Physical Society. By permission.
dc.relation.haspart Rodríguez M. and Törmä P., 2002. Laser-induced collective excitations in a two-component Fermi gas. Physical Review A 66, pages 033601 : 1-6. [article2.pdf] © 2002 American Physical Society. By permission.
dc.relation.haspart Paraoanu Gh.-S., Rodríguez M. and Törmä P., 2001. Cooper pair coherence in a superfluid Fermi gas of atoms. Journal of Physics B: Atomic, Molecular and Optical Physics 34, No. 23, pages 4763-4773. [article3.pdf] © 2001 Institute of Physics Publishing Ltd. By permission.
dc.relation.haspart Paraoanu Gh.-S., Rodríguez M. and Törmä P., 2002. Josephson effect in superfluid atomic Fermi gases. Physical Review A 66, pages 041603 (R) : 1-4. [article4.pdf] © 2002 American Physical Society. By permission.
dc.relation.haspart Rodríguez M., Paraoanu G.-S. and Törmä P., 2001. Vortices in trapped superfluid Fermi gases. Physical Review Letters 87, No. 10, pages 100402 : 1-4. [article5.pdf] © 2001 American Physical Society. By permission.
dc.relation.haspart Rodríguez M. and Törmä P., Bloch oscillations in Fermi gases. Physical Review A, submitted for publication. [article6.pdf] © 2003 by authors and © 2003 American Physical Society. By permission.
dc.subject.other Physics en
dc.subject.other Electrical engineering en
dc.title Signatures of superfluidity in atomic Fermi gases en
dc.type G5 Artikkeliväitöskirja fi
dc.description.version reviewed en
dc.contributor.department Department of Electrical and Communications Engineering en
dc.contributor.department Sähkö- ja tietoliikennetekniikan osasto fi
dc.subject.keyword superfluidity en
dc.subject.keyword Fermi gases en
dc.subject.keyword quantum gases en
dc.subject.keyword Bose-Einstein condensation en
dc.subject.keyword vortices en
dc.identifier.urn urn:nbn:fi:tkk-000971
dc.type.dcmitype text en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.type.ontasot Doctoral dissertation (article-based) en
dc.contributor.lab Laboratory of Computational Engineering en
dc.contributor.lab Laskennallisen tekniikan laboratorio fi

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