Dynamics of interacting dark energy and dark matter model in a curved FLRW scalar field cosmology

ABSTRACT We present a novel investigation of cosmic evolution within a spatially curved Friedmann–Lemaître–Robertson–Walker universe driven by a minimally coupled scalar field that interacts with pressureless dark matter. We introduce a non-minimal interaction term proportional to the energy density of dark matter and the scalar field velocity to account for energy exchange in the dark sector. We adopt an exponential potential and employ dynamical system analysis to derive constraints on model parameters that characterize various cosmological epochs and yield a stable late-time accelerating solution. Furthermore, with various combined data sets, such as the combined CC+BAO+DESI, Pantheon+SH0ES, and CC+BAO+DESI+Pantheon+SH0ES data sets, through the Markov Chain Monte Carlo method, we obtain constraints on the model parameters and evaluate the goodness of fit through the minimum chi-square and reduced chi-square statistics. We explicitly show that a dark energy-dominated universe with slight spatial curvature is consistent with recent cosmological observations and that the Hubble constant is also in good agreement with observations. These findings demonstrate that an interacting scalar-field model in a mildly curved background can successfully reproduce the observed expansion history and offers a viable alternative to Lambda cold dark matter.