6 papers
Finite-Time Bounds on Conformal Vacuum Energy Relaxation in Scalar-Tensor Gravity
Yousef Bisabr
We investigate finite time vacuum energy relaxation in conformally coupled scalar-tensor cosmology distinguishing the suppression accumulated along a physical trajectory from its a…
Scalar Photon Coupling and Modified Photon Evolution: CMB Signatures and Cosmological Constraints
Y. Bisabr
We investigate the constant- limit of a photon-sector modification derived from an early-time interaction between a scalar field and radiation. Starting from the underlying scal…
Constraints on Interacting Early Dark Energy from a Modified Temperature-Redshift Relation and CMB Acoustic Scales
Y Bisabr
The Hubble tension, reflecting a persistent discrepancy between early- and late-time determinations of the Hubble constant, continues to motivate extensions of the standard cosmolo…
Probing Scalar-Photon Coupling in the Early Universe: Implications for CMB Temperature and Anisotropies
Yousef Bisabr
The Hubble tension, as a persistent discrepancy between early-time and late-time measurements of the Hubble constant, motivates explorations of new physics in the early Universe. I…
Interacting Early Dark Energy
Yousef Bisabr
We explore a model of interacting Early Dark Energy (EDE) in which a minimally coupled scalar field, representing the EDE, interacts with the radiation sector through an exponentia…
Can Brans-Dicke Scalar Field Mimic Early Dark Energy?
Yousef Bisabr
We show that a generalisation of Brand-Dicke (BD) theory can provide a theoretical basis for dark energy at early times. This generalisation is based on introducing a potential for…