Non-minimally Coupled Pseudoscalar Inflaton

Abstract

We consider a scenario in which the inflaton $\varphi$ is a pseudoscalar field non-minimally coupled to gravity through a term of the form $\mathcal{X}R{\varphi }^2$. The pseudoscalar is also coupled to a $U(1)$ gauge field (or an ensemble of $\mathcal{N}$ gauge fields) through an axial coupling of the form $\varphi F\tilde{F}$. After M. M. Anber and L. Sorbo, Phys. Rev. D 81, 043534 (2010), Ref. [1], it is well known that this axial coupling leads to a production of gauge particles which acts as a friction term in the dynamics of the inflaton, producing a slow-roll regime even in presence of a steep potential. A remarkable result in this scenario, is that the spectrum of the chiral gravitational waves sourced by the scalar-gauge field interplay can be enhanced due to the non-minimal coupling with gravity, leading to measurable signatures, while maintaining agreement with current observational constraints on $n_s$ and $r$. The inclusion of non-minimal coupling could be helpful to alleviate tensions with non-Gaussianity bounds in models including axial couplings.

Two figures and one appendix added. Several references added. Matches the version accepted for publication in PRD

References in corpus (19)

• The Standard Model Higgs boson as the inflaton
• Large Nongaussianity in Axion Inflation
• N-flationary magnetic fields
• Gravitational waves at interferometer scales and primordial black holes in axion inflation
• Conformal Transformations with Multiple Scalar Fields
• Adding helicity to inflationary magnetogenesis
• UV-Protected Inflation
• The Palatini side of inflationary attractors
• Multifield Dynamics of Higgs Inflation
• Baryon Asymmetry and Gravitational Waves from Pseudoscalar Inflation
• Quantum corrections to quartic inflation with a non-minimal coupling: metric vs. Palatini
• Resurrecting Quadratic Inflation with a non-minimal coupling to gravity
• Universal Constraints on Axions from Inflation
• New universal attractor in nonmininally coupled gravity: Linear inflation
• Phenomenology of fermion production during axion inflation
• Parity-violating and anisotropic correlations in pseudoscalar inflation
• Primordial Perturbations from Multifield Inflation with Nonminimal Couplings
• On the stability and causality of scalar-vector theories
• de Sitter symmetries and inflationary correlators in parity violating scalar-vector models

Cited by in corpus (9)

• Implications of Gravitational-wave Production from Dark Photon Resonance to Pulsar-timing Observations and Effective Number of Relativistic Species
• Towards distinguishing variants of non-minimal inflation
• Natural inflation with a nonminimal coupling to gravity
• Non-minimal (self-)running inflation: metric vs. Palatini formulation
• Multiple point criticality principle and Coleman-Weinberg inflation
• Arbitrarily coupled $p-$forms in cosmological backgrounds
• Chiral gravitational waves and primordial black holes in UV-protected Natural Inflation
• Universality of linear perturbations in SU($N$)-natural inflation
• Correlation functions of sourced gravitational waves in inflationary scalar vector models. A symmetry based approach