Abstract

The standard Lambda Cold Dark Matter (ΛCDM) cosmological model has proven remarkably successful in describing a broad range of observational data, ranging from the CMB to the large-scale structure of the Universe. However, recent advances in precision cosmology have revealed persistent discrepancies between independent data sets and observational methods. The most prominent of these is the Hubble tension, reflecting the disagreement between early- and late-Universe determinations of the Hubble constant. In parallel, recent analyses by the DESI collaboration, combining multiple data sets, have reported evidence for dynamical dark energy in the form of an effective phantom fluid. While such behaviour is difficult to accommodate within minimally coupled dark energy models, it can naturally arise as an effective description of interactions in the dark sector. In this talk, I review the current status of these cosmic tensions and discuss how they may be interpreted as signals of late-time dark sector physics. Focusing on the Dark D-Brane model, in which dark matter and dark energy interact and share a common origin, I will show how dark sector physics can alleviate the cosmic tensions while remaining consistent with current observational constraints.