9 papers
ACT-DR6 consistent inflation in generalised entropic cosmology and gravity
Shin'ichi Nojiri, Sergei D. Odintsov
Within the framework of generalised entropic cosmology and its equivalent gravity, we construct inflationary scenarios consistent with recent Atacama Cosmology Telescope (AC…
May Negative Mass Objects exist in the sky?
Shin'ichi Nojiri, S. D. Odintsov
We conjecture the possibility of negative mass objects (NMOs) existing in the sky. It is shown that they may not be so exotic as usually expected. We show that NMOs appear as solut…
Observational signatures of negative mass wormholes through their shadows
Shin'ichi Nojiri, Sergei D. Odintsov, Diego Sáez-Chillón Gómez
Systems containing objects with negative mass (NMOs) are considered. Such a system consists of one object with positive mass and one NMO, where a bound state exists even though the…
Ghost-free non-local Gravity Compatible with ACT
Shin'ichi Nojiri, S. D. Odintsov, V. K. Oikonomou
We confront the ghost-free non-local gravity theories with the latest Atacama Cosmology Telescope (ACT) constraints on the spectral index of the scalar perturbations and the…
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…
Phantom Crossing and Oscillating Dark Energy with Gravity
Shin'ichi Nojiri, S. D. Odintsov, V. K. Oikonomou
In this work, we shall consider how a dynamical oscillating and phantom crossing dark energy era can be realized in the context of gravity. We approach the topic from a theo…