Conveners
Inflation
- Paride Paradisi (Padova U. and INFN)
The production of gauge fields during inflation, in particular, in the axion inflation model, has a lot of phenomenological applications as it may impact the background inflationary dynamics, alter the spectral properties of primordial scalar and tensor perturbations, and give rise to charged particles via the Schwinger effect. The latter can strongly reduce the efficiency of gauge-field...
The original axion natural inflation model predicts a tensor-to-scalar ratio exceeding experimental limits. In contrast, aligned axion inflation allows for inflationary trajectories that begin near a saddle point of the two-field potential and terminate due to an instability in the orthogonal direction. These solutions are consistent with current observational constraints, and upcoming CMB...
We propose new classes of inflation models based on the modular symmetry, where the modulus field τ serves as the inflaton. We establish a connection between modular inflation and modular stabilization, wherein the modulus field rolls towards a fixed point along the boundary of the fundamental domain. We find the modular symmetry strongly constrain the possible shape of the potential and...
We study classical background electric fields and the Schwinger effect in de Sitter space. We show that having a constant electric field in de Sitter requires the photon to have a tachyonic mass proportional to the Hubble scale. This has physical implications for the induced Schwinger current which affect its IR behaviour. To study this we recompute the Schwinger current in de Sitter space for...
In this talk, I discuss minimal versions of Higgs inflation (HI) in the presence of a massless QCD axion. While the inflationary energy scale of metric HI is too high to be compatible with isocurvature bounds, it was argued that Palatini HI could evade these constraints. I show, however, that an energy-dependent decay constant enhances isocurvature perturbations, implying that axions can at...
In order to shed light on the quantum-to-classical transition of the primordial
perturbations in single field inflation, we investigate the decoherence and associated quantum corrections to the correlation functions of large-scale (superhorizon) scalar curvature perturbations.
The latter are considered as an open quantum system which undergoes quantum decoherence induced by a time-dependent...
