Ponente
Descripción
The persistent  tension and the improved supernova–BAO consistency under dynamical dark energy after DESI DR2 motivate rethinking how dark energy evolution is parametrized. We formulate it directly through the inertial mass density (IMD), $\rho+p$IMD, and show that an IMD evolving from a negative to an equal positive constant toward z->0 can induce a past sign change in  itself, with background constraints from SimpleMC and a full perturbative analysis using CAMB and COBAYA underway. We then turn to the face that cosmology leaves dormant — the genuinely inertial role of IMD — in self-gravitating systems, where at first post-Newtonian order the IMD acquires pressure and gravitational-self-energy contributions whose rescaling by two parameters breaks the strong equivalence principle. The resulting local effects, a Nordtvedt effect and a non-conservation of momentum, are small enough to pass tight Solar-System and pulsar-timing tests, yet the same corrections accumulate on large scales and reshape galactic kinematics as an alternative to dark matter. In short, we present IMD as a single, fundamental variable connecting the dark sector across scales.
