PIRSA:14020152

Large Tensor-to-Scalar Ratio in Small-Field Inflation

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}}
          }

Takeshi Kobayashi SISSA International School for Advanced Studies

Talk numberPIRSA:14020152
DOI10.48660/14020152
Collection
Talk Type Scientific Series
Subject

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.