Oral Presentation

Lattice simulations of axion inflation

Author(s): Angelo Caravano

Presenter: Angelo Caravano (LMU Munich)

If gauge fields are coupled to an axion field during inflation, they can lead to unique observational signatures, such as parity-violating density perturbations and chiral gravitational waves . However, this system often shows nonlinear backreaction effects, invalidating the standard perturbation theory approach. In this talk, I will present the first nonlinear lattice simulation of an axion-U(1) system during inflation. The simulation is used to fully characterize the statistics of the primordial curvature perturbation. We find high-order statistics to be essential in describing non-Gaussianity in the linear regime of the theory. On the contrary, non-Gaussianity is suppressed when the dynamics becomes nonlinear. This relaxes bounds from overproduction of primordial black holes, allowing for parity-violating signatures at large scales.