(Small) resonant non-gaussianities: signatures of a discrete shift symmetry in the effective field theory of inflation
- Theory Group, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)
- School of Natural Sciences, Institute for Advanced Study, Princeton, NJ 08540 (United States)
- CCPP, Physics Department, New York University, 4 Washington Place, New York, NY 10003 (United States)
- Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA 94306 (United States)
We apply the Effective Field Theory of Inflation to study the case where the continuous shift symmetry of the Goldstone boson π is softly broken to a discrete subgroup. This case includes and generalizes recently proposed String Theory inspired models of Inflation based on Axion Monodromy. The models we study have the property that the 2-point function oscillates as a function of the wavenumber, leading to oscillations in the CMB power spectrum. The non-linear realization of time diffeomorphisms induces some self-interactions for the Goldstone boson that lead to a peculiar non-Gaussianity whose shape oscillates as a function of the wavenumber. We find that in the regime of validity of the effective theory, the oscillatory signal contained in the n−point correlation functions, with n > 2, is smaller than the one contained in the 2-point function, implying that the signature of oscillations, if ever detected, will be easier to find first in the 2-point function, and only then in the higher order correlation functions. Still the signal contained in higher-order correlation functions, that we study here in generality, could be detected at a subleading level, providing a very compelling consistency check for an approximate discrete shift symmetry being realized during inflation.
- OSTI ID:
- 22279591
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2012, Issue 12; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
Similar Records
Drifting oscillations in axion monodromy
Drifting oscillations in axion monodromy