Higgs-R² inflation—full slow-roll study at tree-level

Abstract

We consider Higgs inflation with an αR 2 term. This term adds a new scalar degree of freedom, which leads to a two-field model of inflation. We do a complete slow-roll analysis of the three-dimensional parameter space of the R 2 coefficient α, the non-minimal coupling ξ and the Higgs self-coupling λ. We find three classes of inflationary solutions. We also find that pure Higgs inflation is impossible when the

Higgs inflation and teleparallel gravity

“…If the original coupling to the torsion vector is zero (G = 0), the situation corresponds to the Palatini formulation, and we retain a single-field theory with scalar perturbations when adding higher order terms in T (possibly coupled to the scalar field), though not if we add terms that are non-linear in T + 2µ∇ α T α with µ = 0. Likewise, if we consider the metric-equivalent case with P = 1 and G = F , and add higher order terms in T + 2∇ α T α , the scalar perturbations remain, although we get a two-field theory, as is well known in the metric formulation [75,200,[202][203][204][205][206][207][208][209][210][211][212][213][214]. In contrast, if F = G = 0, adding terms non-linear in T or T + 2µ∇ α T α generates a coupling to the torsion vector.…”

Tracing the high energy theory of gravity: an introduction to Palatini inflation

“…11 In principle, the SM Higgs should not be forgotten, and one can ask what is its effect on the inflationary dynamics. It can be shown that the presence of the Higgs alongside the R 2 term leads to multifield inflation in metric gravity, as recently studied in Refs [124][125][126][127][128][129][130][131][132]12.…”

Dynamical emergence of scalaron in Higgs inflation

“…For more comprehensive analysis on the inflationary perturbation, see Refs. [22,[73][74][75][76][77].…”