paper

Mixed Non-Gaussianity from Axion-Gauge Field Dynamics

arXiv:1811.12371 · doi:10.1088/1475-7516/2019/04/044

Abstract

We study scalar-tensor-tensor cross correlation generated by the dynamics of interacting axion and SU(2) gauge fields during inflation. We quantize the quadratic action and solve the linear equations by taking into account mixing terms in a non-perturbative manner. Combining that with the in-in formalism, we compute contributions from cubic interactions to the bispectrum . We find that the bispectrum is peaked at the folded configuration, which is a unique feature encoded by the scalar mixing and localized production of tensor modes. With our parameter choice, the amplitude of the bispectrum is . The unique shape dependence, together with the parity-violating nature, is thus a distinguishing feature to search for in the CMB observables.

19 pages main texts, 8 figures, 2 appendices

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