Cosmological perturbations in a healthy extension of Hořava gravity

Journal Article · Thu Apr 01 04:00:00 EDT 2010 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2010/04/025· OSTI ID:22273359

Kobayashi, Tsutomu; Urakawa, Yuko ^[1]; Yamaguchi, Masahide ^[2]

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1. Department of Physics, Waseda University, Okubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan)
2. Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara 229-8558 (Japan)

In Hořava's theory of gravity, Lorentz symmetry is broken in exchange for renormalizability, but the original theory has been argued to be plagued with problems associated with a new scalar mode stemming from the very breaking of Lorentz symmetry. Recently, Blas, Pujolàs, and Sibiryakov have proposed a healthy extension of Hořava gravity, in which the behavior of the scalar mode is improved. In this paper, we study scalar modes of cosmological perturbations in extended Hořava gravity. The evolution of metric and density perturbations is addressed analytically and numerically. It is shown that for vanishing non-adiabatic pressure of matter the large scale evolution of cosmological perturbations converges to that described by a single constant, ζ, which is an analog of a curvature perturbation on the uniform-density slicing commonly used in usual gravitational theories. The subsequent evolution is thus determined completely by the value of ζ.

• OSTI ID: 22273359
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 04 Vol. 2010; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
COSMOLOGY
DISTURBANCES
GRAVITATION
LORENTZ INVARIANCE
METRICS
SCALARS
SYMMETRY BREAKING