The new ekpyrotic ghost
- Department of Physics, Stanford University, Stanford, CA 94305 (United States)
- Arnold-Sommerfeld-Center for Theoretical Physics, Department of Physics, Ludwig-Maximilians-Universitaet Muenchen, Theresienstrasse 37, D-80333 Munich (Germany)
The new ekpyrotic scenario attempts to solve the singularity problem by involving violation of the null energy condition in a model which combines the ekpyrotic/cyclic scenario with the ghost condensate theory and the curvaton mechanism of production of adiabatic perturbations of the metric. The Lagrangian of this theory, as well as of the ghost condensate model, contains a term with higher derivatives, which was added to the theory to stabilize its vacuum state. We found that this term may affect the dynamics of the cosmological evolution. Moreover, after a proper quantization, this term results in the existence of a new ghost field with negative energy, which leads to a catastrophic vacuum instability. We explain why one cannot treat this dangerous term as a correction valid only at small energies and momenta below some UV cutoff, and demonstrate the problems arising when one attempts to construct a UV completion of this theory.
- OSTI ID:
- 22137843
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2008, Issue 04; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
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