Constraint on momentum-transferred dark energy using DESI DR2

Abstract

In this work, we study two scalar field driven dark energy models characterized by the axion potential and the inverse power-law potential, each coupled to dark matter through momentum exchange. By formulating the dynamics as an autonomous system, we identify the equilibrium points and analyze their stability. To constrain these models, we utilize observational data from Pantheon Plus Type Ia Supernovae, DES Y5, DESI DR2 BAO, and Planck 2018 CMB compressed likelihood, employing Markov Chain Monte Carlo (MCMC) methods. Both potentials exhibit weak to strong preference over the ΛCDM model, with a particularly strong preference for the momentum-coupled scenario when Supernova data are included in the analysis. Furthermore, we find the coupling parameter to be negative, with no lower bound, for both potentials. This finding agrees with previous studies and suggests that momentum-exchange coupling between the dark sectors cannot be ruled out. From the stability analysis, we observe that for both potentials, the late-time attractor corresponds to a dark energy–dominated phase, and the scalar field can behave as a stiff fluid during the early epoch. According to the model selection criteria, the inverse power-law potential is favoured over the axion potential.