Multifield inflation with nonminimal couplings

Abstract

Theories of cosmic inflation suggest that during its early stage, the universe experienced a sudden burst of expansion due to one or more scalar fields. These inflationary models offer exact forecasts for multiple observable variables, such as precise arrangements of temperature differences in the cosmic microwave background radiation. Realistic models of high-energy physics often feature multiple scalar fields, which are expected to have nonminimal connections to spacetime curvature. These connections occur as renormalization counterterms when scalar fields are quantized in a curved spacetime. Within this thesis, I present a recent study that concentrates on multifield inflationary models that include nonminimal couplings within a broad category. One characteristic of these models is their ability to exhibit an impressive attractor behavior. This means that, regardless of the specific couplings and initial conditions, the scalar fields primarily evolve along one particular trajectory for the majority of the inflationary period. This behavior results in reliable predicti