The polynomial potential inflation in light of ACT observations

Abstract: The recent measurements from the Atacama Cosmology Telescope (ACT) favor a higher value of the scalar spectral index $n_s$ compared to the Planck data, challenging many well-established inflationary models. In this work, we investigate the viability of polynomial potential inflation in light of the latest ACT data, focusing on the quadratic ($n=2$) and cubic ($n=3$) models. By exploring the parameter space and deriving constraints on the model coefficients, we find that the cubic model can provide a good fit to the data, while the quadratic model struggles to simultaneously accommodate the ACT data and the requirement of sufficient inflation. Our findings show that higher-order polynomial potentials remain viable for describing cosmic inflation, demonstrating how recent precision measurements continue to refine our understanding of the early Universe.