Non-minimal derivative coupling in Palatini cosmology: acceleration in chaotic inflation potential

Abstract

NMDC-Palatini cosmology in slow-roll regime is of our interests. We present flat FLRW cosmological NMDC-Palatini field equations and acceleration condition. Late time trajectory is approximated. Chaotic inflation potential is considered here as it is viable in a range of positive coupling constant as constrained by CMB results. Phase portraits show that the NMDC-Palatini gives new saddle-point solutions. In $V \propto \phi^2$ potential, the NMDC-Palatini effect enlarges the acceleration-allowed region from that of GR case.