Recent observations from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2) have revealed compelling evidence for dynamical dark energy, challenging the $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) paradigm. In this work, we adopt a data-driven, model-independent approach to reconstruct the dark energy equation of state (EOS) and its potential interaction with dark matter using combined background cosmological datasets, including DESI DR2, cosmic chronometers, observational Hubble data, and type Ia supernovae. Using Gaussian process regression and a nonparametric formalism, we first confirm an $\sim 2\sigma$ indication of dynamical dark energy, featuring a phantom crossing around redshift $z\sim 0.4$, which is consistent with the DESI results. We then explore the implications of dynamical EOS from DESI DR2 for dark sector coupling. Incorporating priors on the EOS from DESI DR2, we find an $\sim 2\sigma$ signal for nonzero interactions between dark energy and dark matter at low redshift. Our results suggest that if DESI’s evidence for time-varying dark energy is confirmed, a coupled dark sector may be a necessary extension beyond $\mathrm{\Lambda }\mathrm{CDM}$.

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• Dark energy
• Evolution of the Universe
• Distances, redshifts, & velocities