Gaussian process reconstructions and model building of quintom dark energy from latest cosmological observations

Abstract In this article we use the latest cosmological observations, including SNe, BAO, CC and RSD, to reconstruct the cosmological evolution via Gaussian process regression. At the background level, we find consistency with quintom dynamics for different data combinations and categorize the characteristics of dark energy into three distinct types: negative-energy dark energy, late-dominated dark energy, and oscillating dark energy. Considering the effect of modified gravity on the growth of matter perturbations, the reconstruction results at the perturbative level indicate that only minor corrections to general relativity are required. Furthermore, we provide theoretical interpretation for these three different types of dynamical dark energy behavior, within the framework of modified gravity, scalar fields, and dark energy equation-of-state parametrizations. Finally, we show that all of these models can be unified within the framework of effective field theory.