Generation of fluctuations during inflation: comparison of stochastic and field-theoretic approaches

dc.creatorFinelli, F.
dc.creatorMarozzi, G.
dc.creatorStarobinsky, A. A.
dc.creatorVacca, G. P.
dc.creatorVenturi, G.
dc.date2008-08-13
dc.date2009-01-25
dc.date.accessioned2026-07-07T12:39:09Z
dc.date.available2026-07-07T12:39:09Z
dc.descriptionWe prove that the stochastic and standard field-theoretical approaches produce exactly the same results for the amount of light massive scalar field fluctuations generated during inflation in the leading order of the slow-roll approximation. This is true both in the case for which this field is a test one and inflation is driven by another field, and the case for which the field plays the role of inflaton itself. In the latter case, in order to calculate the average of the mean square of the gauge-invariant inflaton fluctuation, the logarithm of the scale factor $a$ has to be used as the time variable in the Fokker-Planck equation in the stochastic approach. The implications of particle production during inflation for the second stage of inflation and for the moduli problem are also discussed. The case of a massless self-interacting test scalar field in a de Sitter background with a zero initial renormalized mean square is also considered in order to show how the stochastic approach can easily produce results corresponding to diagrams with an arbitrary number of scalar field loops in the field-theoretical approach (explicit results up to 4 loops inclusive are presented).
dc.descriptionDiscussion expanded, references added, conclusions unchanged, matches the version to be published in Phys. Rev. D
dc.identifierhttps://arxiv.org/abs/0808.1786
dc.identifierhttp://arxiv.org/abs/0808.1786
dc.identifierPhys.Rev.D79:044007,2009
dc.identifierdoi:10.1103/PhysRevD.79.044007
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/219007
dc.subjectHigh Energy Physics - Theory
dc.subjectCosmology and Nongalactic Astrophysics
dc.subjectGeneral Relativity and Quantum Cosmology
dc.titleGeneration of fluctuations during inflation: comparison of stochastic and field-theoretic approaches
dc.typetext

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