PIRSA:14020152 Scientific Series Particle Physics Cosmology

DOI10.48660/14020152

Series: Particle Physics

Kobayashi, T. (2014). Large Tensor-to-Scalar Ratio in Small-Field Inflation. Perimeter Institute. https://pirsa.org/14020152

Kobayashi, Takeshi. Large Tensor-to-Scalar Ratio in Small-Field Inflation. Perimeter Institute, Feb. 25, 2014, https://pirsa.org/14020152 

@misc{ pirsa_PIRSA:14020152,
  doi = {10.48660/14020152},
  url = {https://pirsa.org/14020152},
  author = {Kobayashi, Takeshi},
  keywords = {Particle Physics, Cosmology},
  language = {en},
  title = {Large Tensor-to-Scalar Ratio in Small-Field Inflation},
  publisher = {Perimeter Institute},
  year = {2014},
  month = {feb},
  note = {PIRSA:14020152 see, \url{https://pirsa.org}}
}

Abstract

The production of gravitational waves from cosmic inflation > is normally bounded by the inflaton field excursion. This relation, > which is often referred to as the Lyth bound, claims that > observationally large gravitational waves are produced only if the > inflaton has a super-Planckian field range. In this talk I will point > out that this general belief is not necessarily true when there are > additional light fields producing density perturbations. Perturbations > seeded by the inflaton can be suppressed under such situations, thus > allow large gravitational waves to be produced even from small-field (i.e. > sub-Planckian) inflation. I will also show that the field bound is > taken over by the light field when the inflaton-induced perturbations > are suppressed, thus present a generalized form of the Lyth bound that > applies to the total field space. The calculations are rather simple, > so I will explain my work on a blackboard.

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