Two-field inflation with non-minimal coupling

Abstract

Motivated by the recent `Higgs-inflation' scenario based on a single inflaton field, we consider more generic two-field inflation with non-minimal coupling term. The generic analytic expressions are derived for cosmological observables with the product-separable as well as additive-separable potentials when the non-minimal coupling term is dominated by one of the two fields. A hybrid model of the inflaton potential $V={\mu }^2{\varphi }^2\left[1+\cos (\chi /\sigma )\right]$ with a non-minimal coupling $K=\alpha \varphi$, which guarantees the flatness, is closely examined as a concrete example. Compared to the minimal model with $K=0$, the non-minimal model is shown to provide better fit to the recent cosmological observation by WMAP9 and Planck2013 with the relatively lower field values during the inflationary epoch. Most interestingly, a small value of tensor-to-scalar ratio requires a large non-minimal coupling in our scenario. The model produces non-observably small non-Gaussianity in most of parameter space while a large non-Gaussianity($\sim \mathcal{O}(10)$) is obtainable only when the inflation takes place in a limited field space along the top of the potential.

25 pages, 6 figures, journal published version(v2), meta data updated (v3)

References in corpus (9)

• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Final Maps and Results
• The Standard Model Higgs boson as the inflaton
• Non-Gaussianities in two-field inflation
• Multifield Inflation after Planck: The Case for Nonminimal Couplings
• Non-gaussianity from the second-order cosmological perturbation
• Non-Gaussianities of Single Field Inflation with Non-minimal Coupling
• Hyperbolic Inflation
• Testing Two-Field Inflation

Cited by in corpus (9)

• Reheating in Models with Non-minimal Coupling in metric and Palatini formalisms
• Enhancement of primordial curvature perturbations in $R^3$-corrected Starobinsky-Higgs inflation
• Multifield dynamics of supersymmetric Higgs inflation in SU(5) GUT
• Testing supersymmetric Higgs inflation with non-Gaussianity
• Composite Hybrid Inflation: Dilaton and Waterfall Pions
• Non-minimally assisted chaotic inflation
• Nonminimally Assisted Inflation: A General Analysis
• Two-Field Quintessential Higgs model and the Swampland
• Derivative coupling of inflaton to $R^{(3)}$