Supergravity, $\alpha$-attractors and primordial non-Gaussianity

Abstract

We compute in detail how deviations from Einstein gravity at the inflation energy scale could appear as non-Gaussian features in the sky. To illustrate this we use multi-field $\alpha -$attractor models in the framework of supergravity to realise inflation. We find no obvious obstacle for having choices of model's parameters that generate non-Gaussian features of the equilateral and local type at the $\mathcal{O}$(1) level in the $f_{\mathrm{NL}}$ non-Gaussianity parameter, thus being potentially detectable in future cosmological surveys. This non-Gaussianity has its origin in either the non-canonical kinetic term (which, in turn, is an immediate consequence of assuming an hyperbolic geometry of the moduli space), the interactions of the fields in the potential or the $\alpha -$parameter, or a combination of these three. This opens up the exciting possibility of constraining the law of gravity at energy scales close to the Planck one.

matches version published in JCAP; no major changes, conclusions unchanged

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Cited by in corpus (7)

• Disentangling mass spectra of multiple fields in cosmological collider
• Universality and scaling in multi-field $\alpha$-attractor preheating
• Continuous Spectrum on Cosmological Collider
• Analytic Formulae for Inflationary Correlators with Dynamical Mass
• Two-field Cosmological $\alpha$-attractors with Noether Symmetry
• How Gaussian can the Sky be? Primordial Non-Gaussianity from Quantum Information
• Non-Gaussianities in generalized non-local $R^2$-like inflation