The linear and non-linear dark sector interactions: A cosmological study with DESI DR2 BAO

The dark energy dominated phase of interacting dark energy models acts as the attractor of the system. During the late-times cosmic evolution, this phase may be visualized with the accelerating expansion. We probe the impacts of linear and non-linear interaction forms of interacting dark sector dynamics on the universe evolution and the H 0 tension. We use the numerical solution approach to solve the cosmological equations and apply the Bayesian statistical methods to derive the constraints by using the joint data composed of DESI DR2 BAO (DDR2), Cosmic chronometers (CC) and Pantheon+SH0ES (PS) samples. Subject to the CC+PS+DDR2 results, the constraints on the coupling strength parameters generally allow energy exchange from dark energy to dark matter within 1 σ limits. However, the coupling terms involving matter density may also have energy exchange from the matter into the dark energy sector. The existence of scaling solutions in the models requires the energy exchange from dark energy to dark matter. The energy component appearing in Q affects the cosmic dynamics of their corresponding dominant phase due to the non-linearity associated with forms of Q . The late-times, accelerating universe dynamics possesses a lower extent of Hubble tension in non-linear interacting dark energy models. The use of DESI DR2 BAO in joint Bayesian estimates shifts the corresponding H 0 value towards the Planck result’s value as compared to the CC+PS based estimates. The statistical comparisons among the models suggest that the model with Q = ϵ H ρ d 2 is favored over other interacting dark energy models.