Primordial perturbations in a rainbow universe with running Newton constant

Abstract

We compute the spectral index of primordial perturbations in a rainbow universe. We allow the Newton constant $G$ to run at (super-)Planckian energies and we consider both vacuum and thermal perturbations. If the rainbow metric is the one associated to a generalized Horava-Lifshitz dispersion relation, we find that only when $G$ tends asymptotically to zero can one match the observed value of the spectral index and solve the horizon problem, both for vacuum and thermal perturbations. For vacuum fluctuations the observational constraints imply that the primordial universe expansion can be both accelerating or decelerating, while in the case of thermal perturbations only decelerating expansion is allowed.

7 pages, 2 figures

References in corpus (4)

• Spectral Dimension of the Universe in Quantum Gravity at a Lifshitz Point
• Thermal fluctuations in loop cosmology
• Observing the temperature of the Big Bang through large scale structure
• Thermal Tachyacoustic Cosmology

Cited by in corpus (6)

• Dimension and Dimensional Reduction in Quantum Gravity
• Thermal fluctuations of charged black holes in gravity's rainbow
• Exact solutions and phenomenological constraints from massive scalars in a Gravity's Rainbow spacetime
• Thermal analysis of photon-like particles in rainbow gravity
• Consistent early and late time cosmology from the RG flow of gravity
• Lorentz violation with a universal minimum speed as foundation of de Sitter relativity