3 papers
gr-qc2026
Defocusing dark energy: Raychaudhuri diagnostics beyond and the phantom divide
Özgür Akarsu, Antonio De Felice, N. Merve Uzun
In general relativity, cosmic acceleration is timelike defocusing of the comoving congruence and requires a negative total active gravitational mass density, $\mathcal{M}_{\rm tot}…
gr-qc2024
Unexplored regions in teleparallel gravity: Sign-changing dark energy density
Ozgur Akarsu, Bilal Bulduk, Antonio De Felice +2
While gravity has shown considerable potential in addressing cosmological tensions, we explore previously overlooked solution spaces that hold further promise. We examine th…
astro-ph.CO2023
Quadratic energy-momentum squared gravity: constraints from big bang nucleosynthesis
Ozgur Akarsu, Mariam Bouhmadi-López, Nihan Katirci +1
In this work, we extend the standard cosmological model within the quadratic energy-momentum squared gravity (qEMSG) framework, introducing a nonminimal interaction between the usu…