Abstract
Abstract
Pseudo-scalar inflation coupled with U(1) gauge fields through the Chern-Simons term has
been extensively studied. However, new physics arising from UV theories may still influence the
pseudo-scalar field at low-energy scales, potentially impacting predictions of inflation. In the
realm of effective field theory (EFT), we investigated axion inflation, where operators from heavy
fields are also present, in addition to the axion and gauge fields. The integrated out fields
have two significant effects: the non-linear dispersion regime and coupling heavy modes to the
Chern-Simons term. The first effect changes the propagation of the curvature fluctuation, while
the second one results in additional operators that contribute to curvature fluctuation via
inverse decay. We derived the power spectrum and magnitude of equilateral non-Gaussianity in this
low-energy EFT. We found that the second effect could become significant as the mass of heavy
fields approaches Hubble scale.
Subject
Astronomy and Astrophysics