Challenging the ΛCDM Paradigm: Dark Energy, DESI BAO, and the "Cosmic Calibration Tension"

The standard ΛCDM paradigm faces challenges when confronted with recent observational data, which, if taken at face value, could hint at the existence of new physics in the dark sector. In the first part of this talk, I will provide a brief overview of recent constraints on dark energy derived from various cosmological probes, with a focus on the latest BAO measurements from the DESI collaboration. More specifically, I will discuss dynamical dark energy models that extend beyond the canonical Chevallier-Polarski-Linder (CPL) parametrization. In the second part, I will address the implications of the "SHOES" calibration, demonstrating how this calibration has significant consequences beyond just the Hubble constant (H₀). I will also highlight which modifications are most promising for restoring cosmological concordance.