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キーワード:
High Energy Physics - Theory, hep-th,Astrophysics, Cosmology and Extragalactic Astrophysics, astro-ph.CO,General Relativity and Quantum Cosmology, gr-qc
要旨:
In Ho\v{r}ava-Lifshitz gravity a scaling isotropic in space but anisotropic
in spacetime, often called anisotropic scaling with the dynamical critical
exponent z=3, lies at the base of its renormalizability. This scaling also
leads to a novel mechanism of generating scale-invariant cosmological
perturbations, solving the horizon problem without inflation. In this paper we
propose a possible solution to the flatness problem, in which we assume that
the initial condition of the Universe is set by a small instanton respecting
the same scaling. We argue that the mechanism may be more general than the
concrete model presented here, and rely simply on the deformed dispersion
relations of the theory, and on equipartition of the various forms of energy at
the starting point.
