Kaluza-Klein gravitons are negative energy dust in brane cosmology
- Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka 560-0043 (Japan)
- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)
- APC, Astroparticules et Cosmologie, 11 Place Marcelin Berthelot, F-75005 Paris (France)
We discuss the effect of Kaluza-Klein (KK) modes of bulk metric perturbations on the second Randall-Sundrum (RS II) type brane cosmology, taking the possible backreaction in the bulk and on the brane into account. KK gravitons may be produced via quantum fluctuations during a de Sitter (dS) inflating phase of our brane universe. In an effective 4-dimensional theory in which one integrates out the extra-dimensional dependence in the action, KK gravitons are equivalent to massive gravitons on the brane with masses m>3H/2, where H represents the expansion rate of a dS brane. Thus production of even a tiny amount of KK gravitons may eventually have a significant impact on the late-time brane cosmology. As a first step to quantify the effect of KK gravitons on the brane, we calculate the effective energy density and pressure for a single KK mode. Surprisingly, we find that a KK mode behaves as cosmic dust with a negative energy density on the brane. We note that the bulk energy density of a KK mode is positive definite and there occurs no singular phenomenon in the bulk.
- OSTI ID:
- 20709090
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 71, Issue 8; Other Information: DOI: 10.1103/PhysRevD.71.084019; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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