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Escape from the swampland with a spectator field

Authors :
Kazuhiro Kogai
Yuichiro Tada
Source :
Physical Review D. 101
Publication Year :
2020
Publisher :
American Physical Society (APS), 2020.

Abstract

In the context of string theory, several conjectural conditions have been proposed for low energy effective field theories not to be in swampland, the UV-incomplete class. The recent ones represented by the de Sitter and trans-Planckian censorship conjectures in particular seem to conflict with the inflation paradigm of the early universe. We first point out that scenarios where inflation is repeated several times (multiphase inflation) can be easily compatible with these conjectures. In other words, we relax the constraint on the single inflation for the large scale perturbations to only continue at least around 10 e-folds. In this context, we then investigate if a spectator field can be a source of the almost scale-invariant primordial perturbations on the large scale. As a consequence of such an isocurvature contribution, the resultant perturbations exhibit the nonvanishing non-Gaussianity in general. Also the perturbation amplitude on smaller scales can be completely different from that on the large scale due to the multiplicity of inflationary phases. These signatures will be a smoking gun of this scenario by the future observations.

Details

ISSN :
24700029 and 24700010
Volume :
101
Database :
OpenAIRE
Journal :
Physical Review D
Accession number :
edsair.doi...........f59cb32b661a855b4e10db4260b3c652
Full Text :
https://doi.org/10.1103/physrevd.101.103514