@prefix rdf: . @prefix prodotto: . prodotto:ID5646 rdf:type prodotto:TIPO1101 . @prefix retescientifica: . prodotto:ID5646 rdf:type retescientifica:ProdottoDellaRicerca . @prefix rdfs: . prodotto:ID5646 rdfs:label "ADIABATIC AND ISOCURVATURE PERTURBATIONS FOR MULTIFIELD GENERALIZED EINSTEIN MODELS (Articolo in rivista)"@en . @prefix xsd: . @prefix pubblicazioni: . prodotto:ID5646 pubblicazioni:anno "2003-01-01T00:00:00+01:00"^^xsd:gYear . @prefix skos: . prodotto:ID5646 skos:altLabel "
Di Marco F., Finelli F. and Brandenberger R. (2003)
ADIABATIC AND ISOCURVATURE PERTURBATIONS FOR MULTIFIELD GENERALIZED EINSTEIN MODELS
"^^rdf:HTML ; pubblicazioni:autori "Di Marco F., Finelli F. and Brandenberger R."^^xsd:string ; pubblicazioni:paginaInizio "063512"^^xsd:string ; pubblicazioni:numeroVolume "67"^^xsd:string ; pubblicazioni:note "11 pagine"^^xsd:string ; skos:note "ISI Web of Science (WOS)"^^xsd:string ; pubblicazioni:titolo "ADIABATIC AND ISOCURVATURE PERTURBATIONS FOR MULTIFIELD GENERALIZED EINSTEIN MODELS"^^xsd:string . @prefix prodottidellaricerca: . prodotto:ID5646 prodottidellaricerca:abstract "Low energy effective field theories motivated by string theory will likely contain several scalar moduli fields which will be relevant to early Universe cosmology. Some of these fields are expected to couple with nonstandard kinetic terms to other fields. In this paper, we study the splitting into adiabatic and isocurvature perturbations for a model with two scalar fields, one of which has a nonstandard kinetic term in the Einstein-frame action. Such actions can arise, e.g., in the pre-big-bang and ekpyrotic scenarios. The presence of a coupling through a nonstandard kinetic term induces a novel coupling between adiabatic and isocurvature perturbations which is nonvanishing when the potential for the matter fields is nonzero. This coupling is unsuppressed in the long wavelength limit and thus can lead to an important transfer of power from the entropy to the adiabatic mode on super-Hubble scales. We apply the formalism to the case of a previously found exact solution with an exponential potential and study the resulting mixing of adiabatic and isocurvature fluctuations in this example. We also discuss the possible relevance of the extra coupling in the perturbation equations for the process of generating an adiabatic component of the fluctuation spectrum from isocurvature perturbations without considering a later decay of the isocurvature component." . @prefix istituto: . prodotto:ID5646 prodottidellaricerca:prodottoDi istituto:CDS005 . istituto:CDS005 prodottidellaricerca:prodotto prodotto:ID5646 .