Speaker
Description
We investigate the robustness of inflation models to inhomogeneous initial conditions. In the simplest case inflation is described by a single scalar field $\phi$ minimally coupled to gravity with homogeneous initial value $\phi_0 and canonical momentum $\Pi_0 = 0$. However, there is no fundamental reason to reckon that inflation started with such homogeneous initial conditions. In our recent work we solve numerically Einstein’s equations in 3+1 decomposition to study fast-roll initial conditions i.e., nontrivial $\phi_0$ and $\Pi_0$ for α-attractor (small-field model) and Starobinsky (large-field). We find that for small field inflation, with initial inhomogeneous scalar field profile and homogenous $pi_0$, inflation stops in some regions while in others continues, creating inflating and non-inflating bubbles while for non-homogeneous Π0 evolution depends on the relative phase between initial scalar field profile and initial field momentum. About large field model we find that it is robust to inhomogeneities with large initial kinetic energies up to at least $100V (\phi_0)$ confirming previous results that large field model is more robust than small field one.
