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Non-Gaussianity from preheating
Kari Enqvist1, Asko Jokinen, Anupam Mazumdar
1Helsinki Institute of Physics, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki, Finland.
Physical Review Letters
|May 21, 2005
Summary
Parametric resonance in a two-field inflation model amplifies metric perturbations, significantly boosting non-Gaussianity. This finding may offer a new method for testing cosmic inflation and preheating in future cosmic microwave background experiments.
Area of Science:
- Cosmology
- Theoretical Physics
- Astrophysics
Background:
- Cosmic inflation is a leading theory explaining the early universe's rapid expansion.
- Preheating is a crucial, yet not fully understood, phase following inflation.
- Parametric resonance is a phenomenon where small oscillations amplify over time.
Purpose of the Study:
- To investigate a two-field model of cosmic inflation.
- To explore the impact of parametric resonance on metric perturbations during preheating.
- To quantify the resulting non-Gaussianity in the cosmic microwave background.
Main Methods:
- Utilizing a two-field model for inflation.
- Analyzing the amplification of second-order metric perturbations via parametric resonance.
- Calculating the enhancement of non-Gaussianity from coupled perturbations.
Main Results:
- Parametric resonance significantly amplifies metric perturbations during preheating.
- A considerable enhancement of non-Gaussianity is observed, sourced by local terms.
- The non-Gaussianity parameter, f(NL), can reach approximately 50.
Conclusions:
- The studied inflationary model predicts significant non-Gaussianity.
- This predicted non-Gaussianity could be detectable in future cosmic microwave background experiments.
- The findings offer a potential new observational test for preheating mechanisms in cosmology.