Simple bounds from the perturbative regime of inflation

Journal Article · Fri Aug 15 00:00:00 EDT 2008 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2008/08/007· OSTI ID:22156700

Leblond, Louis ^[1]; Shandera, Sarah ^[2]

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1. George P and Cynthia W Mitchell Institute for Fundamental Physics, Texas A and M University, College Station, TX 77843-4242 (United States)
2. Institute of Strings, Cosmology and Astroparticle Physics, Physics Department, Columbia University, New York, NY 10027 (United States)

We examine the conditions under which a perturbative expansion around an inflating background is valid. When inflation is driven by a single field with a general sound speed, we find a lower limit on the sound speed related to the amplitude of the inflationary power spectrum. Generalizing the sound speed constraints to include scale dependence can limit the number of e-folds obtained in the perturbative regime and restrict otherwise apparently viable models. We also show that, for models with a low sound speed, eternal inflation cannot occur in the perturbative regime.

• OSTI ID: 22156700
• Journal Information: Journal of Cosmology and Astroparticle Physics, Vol. 2008, Issue 08; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
AMPLITUDES
EXPANSION
INFLATIONARY UNIVERSE
LIMITING VALUES
SOUND WAVES
SPECTRA