Anisotropy in a Nonsingular Bounce

Abstract

Following recent claims relative to the question of large anisotropy production in regular bouncing scenarios, we study the evolution of such anisotropies in a model where an Ekpyrotic phase of contraction is followed by domination of a Galileon-type Lagrangian which generates a non-singular bounce. We show that the anisotropies decrease during the phase of Ekpyrotic contraction (as expected) and that they can be constrained to remain small during the non-singular bounce phase (a non-trivial result). Specifically, we derive the e-folding number of the phase of Ekpyrotic contraction which leads to a present-day anisotropy in agreement with current observational bounds.

12 pages, 5 figures

References in corpus (12)

• Covariant Galileon
• New Ekpyrotic Cosmology
• Generating Ekpyrotic Curvature Perturbations Before the Big Bang
• Cosmology without inflation
• A non inflationary model with scale invariant cosmological perturbations
• A classical bounce: constraints and consequences
• Spectra of primordial fluctuations in two-perfect-fluid regular bounces
• Unstable growth of curvature perturbation in non-singular bouncing cosmologies
• Gravitational wave background in perfect fluid quantum cosmologies
• Non-singular string cosmology in a 2d Hybrid model
• Stable Isotropic Cosmological Singularities in Quadratic Gravity
• The Stability of an Isotropic Cosmological Singularity in Higher-Order Gravity

Cited by in corpus (14)

• A Critical Review of Classical Bouncing Cosmologies
• Exploring Bouncing Cosmologies with Cosmological Surveys
• Bouncing cosmology in modified Gauss-Bonnet gravity
• Matter creation in a nonsingular bouncing cosmology
• Non-singular bounce scenarios in loop quantum cosmology and the effective field description
• A $\Lambda$CDM bounce scenario
• Bounce universe from string-inspired Gauss-Bonnet gravity
• Viability of the matter bounce scenario in Loop Quantum Cosmology for general potentials
• Nonsingular bouncing cosmologies in light of BICEP2
• Generalized Galilean Genesis
• Cosmological perturbations in non-local higher-derivative gravity
• Fermi-bounce cosmology and the fermion curvaton mechanism
• Non-Gaussianity excess problem in classical bouncing cosmologies
• Production of non-gaussianities in a bouncing phase