We study the effects of the non-attractor initial conditions for the canonical single-field inflation. The non-attractor stage can last only several e-folding numbers, and should be followed by hilltop inflation. This two-stage evolution leads to large scale suppression in the primordial power spectrum, which is favored by recent observations. Moreover we give a detailed calculation of primordial non-Gaussianity due to the ''from non-attractor to slow-roll'' transition, and find step features in the local and equilateral shapes. We conclude that a plateau-like inflaton potential with an initial non-attractor phase yields interesting features in both power spectrum and bispectrum.
Bibliographical noteFunding Information:
YFC, DGW and ZW are supported in part by the Chinese National Youth Thousand Talents Program and by the USTC start-up funding (Grant No. KY2030000049) and by the National Natural Science Foundation of China (Grant No. 11421303) and by Fund for Fostering Talents in Basic Science of the National Natural Science Foundation of China (Grant No. J1310021). JG acknowledges support from the Korea Ministry of Education, Science and Technology, Gyeongsangbuk-Do and Pohang City for Independent Junior Research Groups at the Asia Pacic Center for Theoretical Physics. JG is also supported in part by a Starting Grant through the Basic Science Research Program of the National Research Foundation of Korea (2013R1A1A1006701) and by a TJ Park Science Fellowship of POSCO TJ Park Foundation.
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- cosmological perturbation theory
- initial conditions and eternal universe