5 papers
Adiabatic Perturbations in GW170817-Compatible Einstein-Gauss-Bonnet Inflation
S. D. Odintsov, V. K. Oikonomou
We study the adiabaticity of the cosmological perturbations in the context of inflationary Einstein-Gauss-Bonnet theories. We focus on viable inflationary Einstein-Gauss-Bonnet the…
ACT Data and Positive Running of the Spectral Index for Scalar Theory and Modified Gravity
S. D. Odintsov, V. K. Oikonomou
In this work we address the possibility of having a positive running of the spectral index in inflationary theories. The recent ACT data indicate mildly that the running of the spe…
Reconstructing ACT-compatible and GW170817-compatible Einstein-Gauss-Bonnet Inflation from the Observational Indices
V. K. Oikonomou
In this work we use an inverse reconstruction technique for constructing ACT-compatible and GW170817-compatible Einstein-Gauss-Bonnet inflationary theories. From a given tensor-to-…
Apparent Phantom Crossing in Gauss-Bonnet Gravity
Shin'ichi Nojiri, Sergei D. Odintsov, V. K Oikonomou
The recent observations of the Dark Energy Spectroscopic Instrument (DESI) indicated the possibility that the dark energy equation of state parameter might change from t…
Is Phantom Divide Crossing in General Relativity Completely Impossible? Shortcomings in canonical and minimally coupled scalar field and Possible Solutions in -essence Models
Shin'ichi Nojiri, S. D. Odintsov, V. K. Oikonomou
General relativity has its successes at the local astrophysical level, however, it seems to be insufficient in describing the Universe at large scales. In this work we investigate…