Robust non-minimal attractors in many-field inflation

Abstract

Multi-field inflation can be inherently non-predictive, with the exception of models with strong attractors. In this work, we focus on models with multiple scalar fields that are non-minimally coupled to the space-time Ricci curvature scalar, motivated by the expectation of a rich particle spectrum at high energies. We show that in this family of models, the single- and multi-field predictions for CMB observables are identical, as long as there exists at least one non-minimal coupling with $\xi \gg 1$. We provide simple expressions for the Hubble scale, the number of $e$-folds, and the turn rate for systems with an arbitrary number of fields and explore the statistical properties for different priors.