2008/02/29 by David Seery, Karim A. Malik, David H. Lyth · 1 citation
Physics and Astronomy · #astro-ph #gr-qc #hep-th
paper · pdf · doi:10.1088/1475-7516/2008/03/014
published as JCAP 0803:014,2008 · 16 pages, uses iopart.sty. v2: replaced with version accepted by JCAP; minor changes of wording only. v3: supersedes version published by journal; typo fixed in Eq. (20) and updated references. v4: sign errors in Eqs. (32) and (38) corrected
arxiv created 2008/05/30 · arxiv updated 2009/12/01
We calculate the tree-level bispectrum of the inflaton field perturbation directly from the field equations, and construct the corresponding fNL parameter. Our results agree with previous ones derived from the Lagrangian. We argue that quantum theory should only be used to calculate the correlators when they first become classical a few Hubble times after horizon exit, the classical evolution taking over thereafter.