Primordial non-Gaussianities of scalar and tensor perturbations in general bounce cosmology: Evading the no-go theorem
Shingo Akama, Shin‐ichi Hirano, Tsutomu Kobayashi
Abstract
It has been pointed out that matter bounce cosmology driven by a k-essence field cannot satisfy simultaneously the observational bounds on the tensor-to-scalar ratio and non-Gaussianity of the curvature perturbation. In this paper, we show that this is not the case in more general scalar-tensor theories. To do so, we evaluate the power spectra and the bispectra of scalar and tensor perturbations on a general contracting background in the Horndeski theory. We then discuss how one can discriminate contracting models from inflation based on non-Gaussian signatures of tensor perturbations.
Topics & Concepts
PhysicsCosmologyNon-GaussianityScalar (mathematics)Scalar–tensor theoryTensor (intrinsic definition)Theoretical physicsCurvatureMathematical physicsGaussianScalar fieldClassical mechanicsQuantum mechanicsMathematicsPure mathematicsGeometryCosmic microwave backgroundAnisotropyCosmology and Gravitation TheoriesGalaxies: Formation, Evolution, PhenomenaSolar and Space Plasma Dynamics