4 papers
Can Distance Duality Violation Save Late-time Solutions to the Hubble Tension?
Yashi Tiwari, Ujjwal Upadhyay, Shao-Jiang Wang +1
The discrepancy between early- and late-Universe determinations of the Hubble constant may point to physics beyond CDM or to unaccounted-for systematics. Numerous late-time mod…
Updated Constraints on Infrared Cutoff Models and Implications for Large-Scale CMB Anomalies
Ujjwal Upadhyay, Yashi Tiwari, Tarun Souradeep
The nearly scale-invariant primordial power spectrum provides the standard initial conditions for cosmological perturbations. However, the largest scales remain only weakly constra…
Revisiting Cosmic Distance Duality with Megamasers and DESI DR2 Observations: Model Independent Constraints on Early-Late Calibration
Brijesh Kanodia, Ujjwal Upadhyay, Yashi Tiwari
The Cosmic Distance Duality Relation (CDDR) connects the angular diameter distance () and the luminosity distance () at a given redshift. This fundamental relation holds…
Exploring cosmological imprints of phantom crossing with dynamical dark energy in Horndeski gravity
Yashi Tiwari, Ujjwal Upadhyay, Rajeev Kumar Jain
In the current era of precision cosmology, the persistence of cosmological tensions, most notably the Hubble tension and the tension, challenges the standard CDM model. T…