Work

Viable cosmology in bimetric theory

Year: 2014

Type: article

Abstract: We study cosmological perturbations in bimetric theory with two fluids each of which is coupled to one of the two metrics. Focusing on a healthy branch of background solutions, we clarify the stability of the cosmological perturbations. For this purpose, we extend the condition for the absence of the so-called Higuchi ghost, and show that the condition is guaranteed to be satisfied on the healthy branch. We also calculate the squared propagation speeds of perturbations and derive the conditions for the absence of the gradient instability. To avoid the gradient instability, we find that the model parameters are weakly constrained.

Source: Journal of Cosmology and Astroparticle Physics

DOI: 10.1088/1475-7516/2014/06/037

Authors: Antonio De Felice, A. Emir Gümrükçüoğ, Shinji Mukohyama, Norihiro Tanahashi, Takahiro Tanaka

Institutions: Kyoto University, Yukawa Institute for Theoretical Physics, Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo, University of Cambridge

Language: English

Topic: Cosmology and Gravitation Theories

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,290