Cosmological perturbations in the projectable version of Hořava-Lifshitz gravity

Journal Article · Mon Aug 01 00:00:00 EDT 2011 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2011/08/015· OSTI ID:22277708

Cerioni, Alessandro ^[1]

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1. Dipartimento di Fisica, Università di Bologna, via Irnerio 46, I-40126 Bologna (Italy)

We consider linear perturbations about a homogeneous and isotropic cosmological background in the projectable version of Hořava-Lifshitz gravity. Starting from the action for cosmological perturbations, we identify the canonically normalized fluctuation variables. We find that - in contrast to what happens in the non-projectable version of the theory - the extra scalar cosmological perturbation mode is already dynamical at the level of linear perturbations and is either ghost-like or tachyonic depending on the value of a free parameter. This indicates a problem for the projectable version of Hořava-Lifshitz gravity.

• OSTI ID: 22277708
• Journal Information: Journal of Cosmology and Astroparticle Physics, Vol. 2011, Issue 08; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
• Country of Publication: United States
• Language: English

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