A Smooth Landscape: Ending Saddle Point Inflation Requires Features to be Shallow
| Autor: | Thorsten Battefeld, Diana Battefeld |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Inflation (cosmology)
Physics High Energy Physics - Theory Cosmology and Nongalactic Astrophysics (astro-ph.CO) Slow roll Field (physics) FOS: Physical sciences Astronomy and Astrophysics Cosmological constant Space (mathematics) Theoretical physics General Relativity and Quantum Cosmology High Energy Physics - Theory (hep-th) Natural units Saddle point Anthropic principle Astrophysics - Cosmology and Nongalactic Astrophysics |
| DOI: | 10.48550/arxiv.1304.0461 |
| Popis: | We consider inflation driven near a saddle point in a higher dimensional field space, which is the most likely type of slow roll inflation on the string theoretical landscape; anthropic arguments need to be invoked in order to find a sufficiently flat region. To give all inflatons large masses after inflation and yield a small but positive cosmological constant, the trajectory in field space needs to terminate in a hole on the inflationary plateau, introducing a curved end-of-inflation hypersurface. We compute non-Gaussianities (bi- and tri-spectrum) caused by this curved hyper-surface and find a negative, potentially large, local non-linearity parameter. To be consistent with current observational bounds, the hole needs to be shallow, i.e. considerably wider than deep in natural units. To avoid singling out our vacuum as special (i.e. more special than a positive cosmological constant entails), we deduce that all features on field space should be similarly shallow, severely limiting the type of landscapes one may use for inflationary model building. We justify the use of a truncated Fourier series with random coefficients, which are suppressed the higher the frequency, to model such a smooth landscape by a random potential, as is often done in the literature without a good a priory reason. Comment: 23 pages, 2 figures; v2: slightly extended to match JCAP version (conclusions unchanged) |
| Databáze: | OpenAIRE |
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