TY  - JOUR
AU  - Creminelli, P.
AU  - Norena, J.
AU  - Pena, M.
AU  - Simonovic, M.
PY  - 2012
DA  - 2012//
TI  - Khronon inflation
T2  - J. Cosmol. Astropart. Phys.
JO  - Journal of Cosmology and Astroparticle Physics
SP  - 032
EP  - 16pp
VL  - 11
IS  - 11
PB  - Iop Publishing Ltd
KW  - inflation
KW  - modified gravity
KW  - non-gaussianity
AB  - We study the possibility that the approximate time shift symmetry during inflation is promoted to the full invariance under time reparametrization t -> (t) over tilde (t), or equivalently under field redefinition of the inflaton phi -> (phi) over tilde(phi). The symmetry allows only two operators at leading order in derivatives, so that all n-point functions of scalar perturbations are fixed in terms of the power spectrum normalization and the speed of sound. During inflation the decaying mode only decays as 1/a and this opens up the possibility to violate some of the consistency relations in the squeezed limit, although this violation is suppressed by the (small) breaking of the field reparametrization symmetry. In particular one can get terms in the 3-point function that are only suppressed by 1/k(L) in the squeezed limit k(L) -> 0 compared to the local shape.
SN  - 1475-7516
UR  - http://arxiv.org/abs/1206.1083
UR  - https://doi.org/10.1088/1475-7516/2012/11/032
DO  - 10.1088/1475-7516/2012/11/032
LA  - English
N1  - WOS:000312263500015
ID  - Creminelli_etal2012
ER  -