Modular Inflation Observables and $j$-Inflation Phenomenology

Abstract

Modular inflation is the restriction to two fields of automorphic inflation, a general group based framework for multifield scalar field theories with curved target spaces, which can be parametrized by the comoving curvature perturbation $\mathcal{R}$ and the isocurvature perturbation tensor $S^{IJ}$. This paper describes the dynamics and observables of these perturbations and considers in some detail the special case of modular inflation as an extensive class of two-field inflation theories with a conformally flat target space. It is shown that the nonmodular nature of derivatives of modular forms leads to CMB observables in modular invariant inflation theories that are in general constructed from almost holomorphic modular forms. The phenomenology of the model of $j$-inflation is compared to the recent observational constraints from the Planck satellite and the BICEP2/Keck Array data.

39 pages, 3 figures. This extended version includes a detailed discussion of the almost holomorphic nature of the physical observables in modular invariant inflation theories

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Cited by in corpus (13)

• Hyperinflation
• Primordial perturbations from inflation with a hyperbolic field-space
• Higgs-Modular Inflation
• Moduli inflation from modular flavor symmetries
• Generalized two-field $\alpha$-attractor models from geometrically finite hyperbolic surfaces
• Hidden symmetries of two-field cosmological models
• Modular Inflation at Higher Level $N$
• Baryogenesis via leptogenesis in multi-field inflation
• Modular Invariant Slow Roll Inflation
• Large and small field inflation from hyperbolic sigma models
• Dilaton-axion modular inflation in supergravity
• Inflationary constraints on the moduli-dependent species scale in modular invariant theories
• Scaling behavior of observables as a model characteristic in multifield inflation