Primordial non-Gaussianity from the DBI Galileons

Physics – High Energy Physics – High Energy Physics - Theory

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

10 pages, 1 figure. Accepted for publication in PRD

Scientific paper

10.1103/PhysRevD.82.103518

We study primordial fluctuations generated during inflation in a class of models motivated by the DBI Galileons, which are extensions of the DBI action that yield second order field equations. This class of models generalises the DBI Galileons in a similar way with K-inflation. We calculate the primordial non-Gaussianity from the bispectrum of the curvature perturbations at leading order in the slow-varying approximations. We show that the estimator for the equilateral-type non-Gaussianity, $f_{\rm NL} ^{equil}$, can be applied to measure the amplitude of the primordial bispectrum even in the presence of the Galileon-like term although it gives a slightly different momentum dependence from K-inflation models. For the DBI Galileons, we find $-0.32 /c_s^2 < f_{\rm NL} ^{equil} < -0.16/c_s^2$ and large primordial non-Gaussianities can be obtained when $c_s$ is much smaller than 1 as in the usual DBI inflation. In G-inflation models, where a de Sitter solution is obtained without any potentials, the non-linear parameter is given by $f_{\rm NL}^{equil} = 4.62 r^{-2/3}$ where $r$ is the tensor to scalar ratio, giving a stringent constraint on the model.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Primordial non-Gaussianity from the DBI Galileons 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 Primordial non-Gaussianity from the DBI Galileons, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Primordial non-Gaussianity from the DBI Galileons will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-684980

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.