106 citations · 168 across the 2 of their papers we have counts for
7 papers
Equivalence of inflationary models between the metric and Palatini formulation of scalar-tensor theories
Laur Järv, Alexandros Karam, Aleksander Kozak +3
With a scalar field non-minimally coupled to curvature, the underlying geometry and variational principle of gravity - metric or Palatini - becomes important and makes a difference…
Single-field inflation in models with an term
Ignatios Antoniadis, Alexandros Karam, Angelos Lykkas +2
We present two cases where the addition of the term to an inflationary model leads to single-field inflation instead of two-field inflation as is usually the case. In both ca…
Frame-dependence of inflationary observables in scalar-tensor gravity
Alexandros Karam, Thomas Pappas, Kyriakos Tamvakis
By means of the Green's function method, we computed the spectral indices up to third order in the slow-roll approximation for a general scalar-tensor theory in both the Einstein a…
Rescuing Quartic and Natural Inflation in the Palatini Formalism
I. Antoniadis, A. Karam, A. Lykkas +2
When considered in the Palatini formalism, the Starobinsky model does not provide us with a mechanism for inflation due to the absence of a propagating scalar degree of freedom. By…
Palatini inflation in models with an term
I. Antoniadis, A. Karam, A. Lykkas +1
The Starobinsky model, considered in the framework of the Palatini formalism, in contrast to the metric formulation, does not provide us with a model for inflation, due to the abse…
Frame-dependence of higher-order inflationary observables in scalar-tensor theories
Alexandros Karam, Thomas Pappas, Kyriakos Tamvakis
In the context of scalar-tensor theories of gravity we compute the third-order corrected spectral indices in the slow-roll approximation. The calculation is carried out by employin…