Abstract
We present a general framework where the effective field theory of single field inflation is extended by the inclusion of operators with mass dimension 3 and 4 in the unitary gauge. These higher dimensional operators introduce quartic and sextic corrections to the dispersion relation. We study the regime of validity of this extended effective field theory of inflation and the effect of these higher dimensional operators on CMB observables associated with scalar perturbations, such as the speed of sound, the amplitude of the power spectrum and the tensor-to-scalar ratio. Tensor perturbations remain instead, unaltered.
Highlights
To adding only operators with time dependence and at most linear in terms of g00, before performing the Stuckelberg trick
We present a general framework where the effective field theory of single field inflation is extended by the inclusion of operators with mass dimension 3 and 4 in the unitary gauge
We study the regime of validity of this extended effective field theory of inflation and the effect of these higher dimensional operators on CMB observables associated with scalar perturbations, such as the speed of sound, the amplitude of the power spectrum and the tensor-to-scalar ratio
Summary
We start by reviewing the EFToI framework which allows one to write down the most generic action for single scalar field models on a quasi de Sitter background. One can start by writing the most general 3diff invariant action around the FRW metric and the effect of different terms. This implies, in addition to standard 4-diff invariant metric terms, including g00 and pure functions of time f (t) that are scalars under 3-diffs. Since we are interested in deviations from the standard slow-roll model, we will turn on the coefficients of the operators in Lm. In the EFToI, focusing only on the terms that contribute to the quadratic action of π and can change the dispersion relation up to quartic order, the unitary gauge action is LEFToI = Lslow−roll + L2 ,. (δ K μμ ) and ν μ are the operators that lead to generalized Ghost Inflation with a quartic correction to the dispersion relation [1, 5]
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