Author:
Cruces Diego,Germani Cristiano,Palomares Adrian
Abstract
Abstract
In this paper, we generalize the Weinberg's procedure to determine the comoving curvature
perturbation ℛ to non-attractor inflationary regimes. We show that both modes of ℛ
are related to a symmetry of the perturbative equations in the Newtonian gauge. As a byproduct,
we clarify that adiabaticity does not generally imply constancy of ℛ, not even in the
k ⟶ 0 limit. We then show that there exist non-equivalent definitions of δN
that would reproduce ℛ or the uniform density curvature perturbation ζ at linear
order. We have then shown that the perturbative δN definition in terms of difference
between the number of e-foldings of different gauges, can be extended non-perturbatively at
leading order in gradient expansion. Nevertheless, the computer friendly definition in terms of
the difference of e-foldings obtained from the evolution of a local FRW Universe, respectively
with perturbed and un-perturbed initial conditions, might only give information about the linear
order curvature perturbations, contrary to what is stated in the literature.
Subject
Astronomy and Astrophysics
Cited by
1 articles.
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