On the Effective Field Theory for Quasi-Single Field Inflation

Abstract

We study the effective field theory (EFT) description of the virtual particle effects in quasi-single field inflation, which unifies the previous results on large mass and large mixing cases. By using a horizon crossing approximation and matching with known limits, approximate expressions for the power spectrum and the spectral index are obtained. The error of the approximate solution is within 10% in dominate parts of the parameter space, which corresponds to less-than-0.1% error in the $n_s$-$r$ diagram. The quasi-single field corrections on the $n_s$-$r$ diagram are plotted for a few inflation models. Especially, the quasi-single field correction drives $m^2{\varphi }^2$ inflation to the best fit region on the $n_s$-$r$ diagram, with an amount of equilateral non-Gaussianity which can be tested in future experiments.

12 pages, 5 figures. v2: references added

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Cited by in corpus (3)

• On the inflationary massive field with a curved field manifold
• Non-Gaussianity from $X,Y$ gauge bosons in Cosmological Collider Physics
• Schwinger-Keldysh mechanism in extended quasi single field inflation