Non-gaussianity in axion N-flation models: detailed predictions and mass spectra

Abstract

We have recently shown that multi-field axion N-flation can lead to observable non-gaussianity in much of its parameter range, with the assisted inflation mechanism ensuring that the density perturbations are sufficiently close to scale invariance. In this paper we extend our analysis in several directions. In the case of equal-mass axions, we compute the probability distributions of observables and their correlations across the parameter space. We examine the case of unequal masses, and show that the mass spectrum must be very densely packed if the model is to remain in agreement with observations. The model makes specific testable predictions for all major perturbative observables, namely the spectral index, tensor-to-scalar ratio, bispectrum, and trispectrum.

9 pages, 12 fgures

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• Large trispectrum in two-field slow-roll inflation
• Probability of Slowroll Inflation in the Multiverse
• No-boundary measure and preference for large e-foldings in multi-field inflation
• Designing and testing inflationary models with Bayesian networks
• Influence of Reheating on the Trispectrum and its Scale Dependence
• BICEP2, the curvature perturbation and supersymmetry
• Evidence for Inflation in an Axion Landscape
• Non-Gaussianity after many-field reheating