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

## TL;DR

This paper explores how non-minimal derivative coupling in Palatini cosmology affects cosmic acceleration, especially in chaotic inflation models, revealing new saddle points and an enlarged acceleration region compared to General Relativity.

## Contribution

It introduces the flat FLRW cosmological equations for NMDC-Palatini theory and demonstrates its impact on acceleration regions in chaotic inflation potentials.

## Key findings

- NMDC-Palatini theory introduces new saddle-point solutions.
- Enlarges the acceleration-allowed region in quadratic potential.
- Compatible with CMB constraints on positive coupling constants.

## 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.