Dynamic vacuum variable and equilibrium approach in cosmology
arXiv:0806.2805 · doi:10.1103/PhysRevD.78.063528
Abstract
A modified-gravity theory is considered with a four-form field strength F, a variable gravitational coupling parameter G(F), and a standard matter action. This theory provides a concrete realization of the general vacuum variable q as the four-form amplitude F and allows for a study of its dynamics. The theory gives a flat Friedmann-Robertson-Walker universe with rapid oscillations of the effective vacuum energy density (cosmological "constant"), whose amplitude drops to zero asymptotically. Extrapolating to the present age of the Universe, the order of magnitude of the average vacuum energy density agrees with the observed near-critical vacuum energy density of the present universe. It may even be that this type of oscillating vacuum energy density constitutes a significant part of the so-called cold dark matter in the standard Friedmann-Robertson-Walker framework.
24 (not 25) pages, v7(=v6 with latex problem corrected): published version in preprint style
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Cited by in corpus (6)
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- z=3 Lifshitz-Horava model and Fermi-point scenario of emergent gravity
- Emergent gravity: the BEC paradigm
- Equilibrium boundary conditions, dynamic vacuum energy, and the Big Bang
- Lorentz invariance, vacuum energy, and cosmology
- UHECR bounds on Lorentz violation in the photon sector