Symmetry breaking patterns for inflation
Abstract
We study inflationary models where the kinetic sector of the theory has a nonlinearly realised symmetry which is broken by the inflationary potential. We distinguish between kinetic symmetries which nonlinearly realise an internal or spacetime group, and which yield a flat or curved scalar manifold. This classification leads to wellknown inflationary models such as monomial inflation and αattractors, as well as a new model based on fixed couplings between a dilaton and many axions which nonlinearly realises higherdimensional conformal symmetries. In this model, inflation can be realised along the dilatonic direction, leading to a tensortoscalar ratio r ∼ 0 .01 and a spectral index n _{ s } ∼ 0 .975. We refer to the new model as ambient inflation since inflation proceeds along an isometry of an antide Sitter ambient spacetime, which fully determines the kinetic sector.
 Publication:

Journal of High Energy Physics
 Pub Date:
 June 2018
 DOI:
 10.1007/JHEP06(2018)006
 arXiv:
 arXiv:1712.05760
 Bibcode:
 2018JHEP...06..006K
 Keywords:

 Effective Field Theories;
 Global Symmetries;
 SpaceTime Symmetries;
 High Energy Physics  Theory;
 General Relativity and Quantum Cosmology
 EPrint:
 References added, discussion of WessZumino term extended