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Scalar-fluid theories: cosmological perturbations and large-scale structure
Stockholm University, Nordic Institute for Theoretical Physics (Nordita).
Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Pontificia Universidad Catolica de Valparaiso, Chile.
Number of Authors: 3
2015 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, no 9, 047Article in journal (Refereed) Published
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
2015. no 9, 047
Keyword [en]
dark energy theory, cosmological perturbation theory
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
URN: urn:nbn:se:su:diva-124778DOI: 10.1088/1475-7516/2015/09/047ISI: 000365690000047OAI: oai:DiVA.org:su-124778DiVA: diva2:890709
Available from: 2016-01-04 Created: 2016-01-04 Last updated: 2016-01-04Bibliographically approved

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Koivisto, Tomi S.
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Nordic Institute for Theoretical Physics (Nordita)
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