Nongaussian and nonscale-invariant perturbations from tachyonic preheating in hybrid inflation

Details Nongaussian and nonscale-invariant perturbations from tachyonic preheating in hybrid inflation Nongaussian and nonscale-invariant perturbations from tachyonic preheating in hybrid inflation

2006-01-20

arxiv.org/abs/astro-ph/0601481v2

Phys.Rev. D73 (2006) 106012

Astronomy and Astrophysics

Astrophysics

31 pages, 15 figures. Typos corrected. References added. Discussion added about the accuracy of the approximate solutions for

Scientific paper

10.1103/PhysRevD.73.106012

We show that in hybrid inflation it is possible to generate large second-order perturbations in the cosmic microwave background due to the instability of the tachyonic field during preheating. We carefully calculate this effect from the tachyon contribution to the gauge-invariant curvature perturbation, clarifying some confusion in the literature concerning nonlocal terms in the tachyon curvature perturbation; we show explicitly that such terms are absent. We quantitatively compute the nongaussianity generated by the tachyon field during the preheating phase and translate the experimental constraints on the nonlinearity parameter f_{NL} into constraints on the parameters of the model. We also show that nonscale-invariant second-order perturbations from the tachyon field can become larger than the inflaton-generated first-order perturbations, leading to stronger constraints than those coming from nongaussianity. The width of the excluded region in terms of the logarithm of the dimensionless coupling g, grows linearly with the log of the ratio of the Planck mass to the tachyon VEV, \log(M_p/v); hence very large regions are ruled out if the inflationary scale v is small. We apply these results to string-theoretic brane-antibrane inflation, and find a stringent upper bound on the string coupling, g_s < 10^{-4.5}.

Affiliated with

Also associated with

No associations

Rating

Nongaussian and nonscale-invariant perturbations from tachyonic preheating in hybrid inflation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Nongaussian and nonscale-invariant perturbations from tachyonic preheating in hybrid inflation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nongaussian and nonscale-invariant perturbations from tachyonic preheating in hybrid inflation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-9324