Non-metric chaotic inflation

作者：Enqvist Kari^*; Koivisto Tomi; Rigopoulos Gerasimos

来源：Journal of Cosmology and Astroparticle Physics, 2012, (5): 023.

DOI：10.1088/1475-7516/2012/05/023

• modified gravity
• inflation

We consider inflation within the context of what is arguably the simplest non-metric extension of Einstein gravity. There non-metricity is described by a single graviscalar field with a non-minimal kinetic coupling to the inflaton field Psi, parameterized by a single parameter gamma. There is a simple equivalent description in terms of a massless field and an inflaton with a modified potential. We discuss the implications of non-metricity for chaotic inflation and find that it significantly alters the inflaton dynamics for field values Psi greater than or similar to M-P/gamma, dramatically changing the qualitative behaviour in this regime. In the equivalent single-field description this is described as a cuspy potential that forms of barrier beyond which the inflation becomes a ghost field. This imposes an upper bound on the possible number of e-folds. For the simplest chaotic inflation models, the spectral index and the tensor-to-scalar ratio receive small corrections dependent on the non-metricity parameter. We also argue that significant post-inflationary non-metricity may be generated.

• 出版日期2012-5