Conveners
Effective field theory for chiral gravitational waves in axion inflation
- Tomohiro Fujita
Description
Axions are well-motivated inflaton candidates that naturally couple to gauge fields via the Chern–Simons interaction. When the gauge field is non-Abelian, an isotropic background can form during inflation, producing strongly chiral gravitational waves—a phenomenon studied in chromo-natural inflation and related models. We develop an effective field theory (EFT) that generalizes these scenarios, showing that chiral gravitational waves arise generically from axion–gauge field dynamics. The framework also clarifies stability conditions and provides a unified basis for studying signals potentially detectable in forthcoming CMB experiments such as the Simons Observatory.
