Constant-roll in the Palatini-R² models

Abstract

We consider models of a scalar field coupled to quadratic R+R 2 gravity in the framework of the Palatini formulation. The resulting Einstein-frame generalized k-inflation effective theory is analyzed assuming that the constant-roll condition holds. We focus on a quartic selfinteraction potential, a case of particular appeal modelling Higgs inflation, considering the cases of minimal and non-minimal coupling of the inflaton to gravity. For an appropriate range of the model parameters in the large field domain the obtained values for the inflationary observables are found in agreement with current observations.

Quintessential Inflation with Dynamical Higgs Generation as an Affine Gravity

“…Let us specifically stress that this mechanism is different from the widely discussed scenario of Higgs inflation, where the Higgs field triggers the inflation in the "early" universe through a non-minimal coupling to gravity [99][100][101][102][103][104][105][106][107][108][109][110][111][112][113][114]. In our scenario the impact of the Higgs field dynamics starts after end of inflation.…”

Quintessential Inflation with Dynamical Higgs Generation as an Affine Gravity

“…The non-trivial symmetry-breaking Higgs vacuum is dynamically generated in the post-inflationary epoch. This mechanism is different from another widely discussed scenario where the Higgs field pushes the inflation in the "early" universe through a non-minimal coupling to gravity [86][87][88][89][90][91][92][93][94][95][96][97][98][99][100].…”

Anisotropic constant-roll inflation for the Dirac–Born–Infeld model

“…Consequently, the constant-roll inflation has been investigated extensively in Refs. [115][116][117][118][119][120][121][122][123][124][125][126][127][128][129][130][131][132][133]. It appears that the constant-roll condition has been applied to a number of cosmological models such as the non-minimal Coleman-Weinberg [119], F(R) gravity [120][121][122][123], scalar-tensor gravity [124], k-inflation [125], non-canonical scalar field [126], DBI [127], Palatini-R 2 gravity [128], Gauss-Bonnet gravity [129,130], multi scalar fields [131], non-commutative gravity [132], and f (φ)R gravity [133] models to figure out either novel (exact) inflationary solutions or cosmological consequences.…”