Primordial non-Gaussianity from the DBI Galileons

By S. Mizuno, K. Koyama. 2010

153 citations recorded by the source corpus.

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 generalizes 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, fNLequil, 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/cs2

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/35c6f791d1c8a370787c8335bc4ec1277ac323b4

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. I. Sawicki
2. Pedro G. Ferreira
3. Claudia de Rham
4. Tsutomu Kobayashi
5. Antonio Padilla
6. T. Clifton
7. C. Skordis
8. O. Pujolàs

In Nuclear and High Energy Physics

1. I. Sawicki
2. Claudia de Rham
3. Pedro G. Ferreira
4. Antonio Padilla
5. O. Pujolàs
6. A. Tolley
7. T. Clifton
8. Lavinia Heisenberg

Citations in the corpus

• Effective field theory approach to quasi-single field inflation and effects of heavy fields (2012, background): “Then, the bispectra of primordial curvature [10–15] and tensor perturbations [16, 17] are obtained as well as their powerspectra [4].”
• Galileon inflation (2010, methodology): “gave background solutions and studied the two-point correlation function of perturbations; threepoint correlations in this model were later considered by Mizuno & Koyama [18].”
• Beyond the Cosmological Standard Model (2014, unknown): “This theory has been extensively studied in many contexts including inflation [142, 440, 443] and late time acceleration.”
• Modified Gravity and Cosmology (2011, background): “Constraints on the model coming from large scale structure and non-Gaussianity have been obtained in [693, 903], respectively.”
• The imperfect fluid behind kinetic gravity braiding (2011, background): “Nonetheless, these theories have been named galileon theories and a significant body of work has already been carried out analysing their impact not only on cosmological solutions [28–45], but also in other circumstances [46–55].”