The physical squeezed limit: consistency relations at order q(2)

作者：Creminelli Paolo^*; Perko Ashley; Senatore Leonardo; Simonovic Marko; Trevisan Gabriele

来源：Journal of Cosmology and Astroparticle Physics, 2013, (11): 015.

DOI：10.1088/1475-7516/2013/11/015

• inflation
• non-gaussianity
• cosmological perturbation theory

In single-field models of inflation the effect of a long mode with momentum q reduces to a diffeomorphism at zeroth and first order in q. This gives the well-known consistency relations for the n-point functions. At order q(2) the long mode has a physical effect on the short ones, since it induces curvature, and we expect that this effect is the same as being in a curved FRW universe. In this paper we verify this intuition in various examples of the three-point function, whose behaviour at order q(2) can be written in terms of the power spectrum in a curved universe. This gives a simple alternative understanding of the level of non-Gaussianity in single-field models. Non-Gaussianity is always parametrically enhanced when modes freeze at a physical scale k(ph), (f) shorter than H: f(NL) similar to (k(ph), (f)/H)(2).

• 出版日期2013-11