Constraining the detailed balance condition in Hořava gravity with cosmic accelerating expansion
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan, R.O.C. (China)
- Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei 10617, Taiwan, R.O.C. (China)
In 2009 Hořava proposed a power-counting renormalizable quantum gravity theory. Afterwards a term in the action that softly violates the detailed balance condition has been considered with the attempt of obtaining a more realistic theory in its IR-limit. This term is proportional to ωR{sup (3)}, where ω is a constant parameter and R{sup (3)} is the spatial Ricci scalar. In this paper we derive constraints on this IR-modified Hořava theory using the late-time cosmic accelerating expansion observations. We obtain a lower bound of |ω| that is nontrivial and depends on Λ{sub W}, the cosmological constant of the three dimensional spatial action in the Hořava gravity. We find that to preserve the detailed balance condition, one needs to fine-tune Λ{sub W} such that −2.29 × 10{sup −4} < (c{sup 2}Λ{sub W})/(H{sup 2}{sub 0}Ω{sub DE})−2 < 0, where H{sub 0} and Ω{sub DE} are the Hubble parameter and dark energy density fraction in the present epoch, respectively. On the other hand, if we do not insist on the detailed balance condition, then the valid region for Λ{sub W} is much relaxed to −0.39 < (c{sup 2}Λ{sub W})/(H{sup 2}{sub 0}Ω{sub DE})−2 < 0.12. We find that although the detailed balance condition cannot be ruled out, it is strongly disfavored.
- OSTI ID:
- 22275456
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2010, Issue 10; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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