106 citations · 106 across the 1 of their papers we have counts for
8 papers
Palatini-Higgs inflation with non-minimal derivative coupling
Ioannis D. Gialamas, Alexandros Karam, Angelos Lykkas +1
The predictions of standard Higgs inflation in the framework of the metric formalism yield a tensor-to-scalar ratio which lies well within the expected accuracy of…
General parametrization of higher-dimensional black holes and its application to Einstein-Lovelock theory
Roman A. Konoplya, Thomas D. Pappas, Zdenek Stuchlík
Here we have developed the general parametrization for spherically symmetric and asymptotically flat black-hole spacetimes in an arbitrary metric theory of gravity. The parametriza…
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…
Einstein-scalar-Gauss-Bonnet black holes: Analytical approximation for the metric and applications to calculations of shadows
Roman A. Konoplya, Thomas Pappas, Alexander Zhidenko
Recently, numerical solutions to the field equations of Einstein-scalar-Gauss-Bonnet gravity that correspond to black-holes with non-trivial scalar hair have been reported. Here, w…
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…