Title: CMB from EFT
Speaker: Dr. Sayantan Choudhury, Department of Theoretical Physics, Tata Institute of Fundamental Research, Mumbai
Venue: IOP Lecture Hall
Date: 2016-Oct-26 16:00:00
Abstract: In this work, we study the Effective Field Theory (EFT) of inflation for
quasi single field which describes the most general theoretical framework
for quantum fluctuations around a quasi de Sitter background. Based on the
time dependent spatial diffeomorphism, which is not broken by the time
dependent background evolution, the most generic action is constructed with
lowest dimensional Wilsoinan EFT operators up to third order in
fluctuations in unitary gauge. Using this setup, further we compute the the
two point function (power spectrum) and three point function (bispectrum)
for scalar fluctuations using In-In (Swinger Keldysh) formalism. In
particular, we discuss two limiting shape configurations in momentum space
- equilateral limit and squeezed limit from three point function
(bispectrum) for scalar fluctuations. Additionally, we also provide the
results for two point function (power spectrum) for tensor (graviton)
fluctuations. Finally, using the results for the three point function
(bispectrum) for scalar fluctuations we compute the analytical expressions
for the Wilsoinan EFT coefficients for canonical single field slow roll
models of inflation and general single field models of inflation
($P(X,phi)$ theory which includes any possible form of non-canonical
interactions. Example: DBI inflation and Tachyon inflation in String
Theory) in the equilateral and squeezed limiting configurations.
