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Scalar-fluid theories: cosmological perturbations and large-scale structure
KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.ORCID iD: 0000-0002-9403-8565
2015 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, no 9, 047Article in journal (Refereed) PublishedText
Abstract [en]

Recently a new Lagrangian framework was introduced to describe interactions between scalar fields and relativistic perfect fluids. This allows two consistent generalizations of coupled quintessence models: non-vanishing pressures and a new type of derivative interaction. The implications of these to the formation of cosmological large-scale structure are uncovered here at the linear order. The full perturbation equations in the two cases are derived in a unified formalism and their Newtonian, quasi-static limit is studied analytically. Requiring the absence of an effective sound speed term in the coupled dark matter fluid restricts the Lagrangian to be a linear function of the matter number density. This leaves new potentially viable classes of both algebraically and derivatively interacting models wherein the coupling may impact the background expansion dynamics and imprint new signatures into the large-scale structure.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2015. no 9, 047
Keyword [en]
dark energy theory, cosmological perturbation theory
National Category
Astronomy, Astrophysics and Cosmology
URN: urn:nbn:se:kth:diva-180165DOI: 10.1088/1475-7516/2015/09/047ISI: 000365690000047ScopusID: 2-s2.0-84947588288OAI: diva2:893165

QC 20160112

Available from: 2016-01-12 Created: 2016-01-07 Last updated: 2016-01-12Bibliographically approved

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Koivisto, Tomi S.
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Nordic Institute for Theoretical Physics NORDITA
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ReferencesLink to record
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