Curvaton with nonminimal derivative coupling to gravity: Full perturbation analysis

2014/09/30 by Kaixi Feng, Taotao Qiu · 24 citations
Mathematics · Physics and Astronomy · #Anisotropy #Cosmic microwave background #Cosmology and Gravitation Theories #Coupling constant #Equilateral triangle #Galaxies: Formation, Evolution, Phenomena #Geometry #Mathematical physics #Mathematics #Non-Gaussianity #Perturbation (astronomy) #Perturbation theory (quantum mechanics) #Physics #Quantum mechanics #Scalar (mathematics) #Solar and Space Plasma Dynamics #Tensor (intrinsic definition) #astro-ph.HE #gr-qc #hep-ph #hep-th

paper · pdf · doi:10.1103/physrevd.90.123508

published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 90(12) (American Physical Society) · Published in Phys.Rev. D90 (2014) 123508

openalex publication_date 2014/12/05 · arxiv created 2014/12/10 · arxiv updated 2014/12/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

In our previous paper [K. Feng, T. Qiu, and Y.-S. Piao, Phys. Lett. B 729, 99 (2014)], we have shown a curvaton model where the curvaton has a nonminimal derivative coupling to gravity. Such a coupling could cause scale invariance of the perturbations for a wide range of constant values of the equation of state of the cosmic background at the early time. In this paper, we continue our study by fully analyzing its perturbations up to the third order. Apart from the usual 2-point correlation function that have already been calculated in Feng, Qiu, and Piao [Phys. Lett. B 729, 99 (2014)], we also take into account the 3-point correlation functions, including the pure scalar part, the pure tensor part, and the cross-correlations between scalar and tensor perturbation modes. We find that for the pure scalar part, the 3-point correlation functions can generate non-Gaussianities that fit the PLANCK data very well. For the pure tensor and mixed parts, the shape functions have peaks at squeezed and equilateral limits, respectively, responsible for sizable f_NL^sqz and f_NL^eql, which could be tested by the future observational data.

Citations

• Curvaton with nonminimal derivative coupling to gravity
• Second-order scalar-tensor field equations in a four-dimensional space
• Generalized Galileons: All scalar models whose curved background extensions maintain second-order field equations and stress tensors
• Signatures of non-Gaussianity in the curvaton model
• Primordial density perturbation in the curvaton scenario
• Scale dependence of localfNL

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