Non-Gaussianity from the second-order cosmological perturbation
By D. Lyth, Yeinzon Rodriguez Department of Physics Lancaster University, C. D. I. U. A. Narino. 2005
139 citations recorded by the source corpus.
Several conserved and/or gauge-invariant quantities described as the second-order curvature perturbation have been given in the literature. We revisit various scenarios for the generation of second-order non-Gaussianity in the primordial curvature perturbation {zeta}, employing for the first time a unified notation and focusing on the normalization f{sub NL} of the bispectrum. When {zeta} first appears a few Hubble times after horizon exit, |f{sub NL}| is much less than 1 and is, therefore, negligible. Thereafter {zeta} (and hence f{sub NL}) is conserved as long as the pressure is a unique function of energy density (adiabatic pressure). Nonadiabatic pressure comes presumably only from the effect of fields, other than the one pointing along the inflationary trajectory, which are light during inflation ('light noninflaton fields'). During single-component inflation f{sub NL} is constant, but multicomponent inflation might generate vertical bar f{sub NL} vertical bar {approx}1 or bigger. Preheating can affect f{sub NL} only in atypical scenarios where it involves light noninflaton fields. The simplest curvaton scenario typically gives f{sub NL}<<-1 or f{sub NL}=+5/4. The inhomogeneous reheating scenario can give a wide range of values for f{sub NL}. Unless there is a detection, observation can eventually provide a limit vertical bar f{sub NL} vertical barmore » or approx. 1, at which level it will be crucial to calculate the precise observational limit using second-order theory.« less
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/763b6e5c864e264abf1df0387eeb52f20af724be
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Citations in the corpus
- Non-Gaussianity in curvaton models with nearly quadratic potentials (2005, unknown): “∗E-mail: kari.enqvist@helsinki.fi †E-mail: sami.nurmi@helsinki.fi Contents”
- Primordial non-Gaussianities in single-field inflation (2005, unknown): “ in the comoving gauge, where the three-dimensional slices implicit in (21) are chosen so that the inflaton perturbation δφvanishes. On slices where δφ = 0, the three-dimensional metric takes the form [27, 41]§ h ij = a 2(t)e Rδ ij, (22) where the field Ehas been gauged away by an appropriate choice o”
- Primordial non-Gaussianities from multiple-field inflation (2005, background): “P 09(2005)011 Keywords: cosmological perturbation theory, inflation, cosmology of theories beyond the SM, physics of the early universe ArXiv ePrint: astro-ph/0506056 c©2005 IOP Publishing Ltd 1475-7516/05/090011+24$30.00 JC A P 09(2005)011 Contents”