Abstract
Abstract We investigate a novel realization of warm inflation driven by the Standard Model (SM) Higgs field within the Palatini formulation of gravity, supplemented by an $$R^2$$ R 2 curvature correction. By incorporating dissipative dynamics and a thermal radiation bath, our model eliminates the need for a separate reheating phase and naturally flattens the inflationary potential. We derive the slow-roll dynamics in the strong dissipation regime, compute the resulting inflationary observables, and demonstrate compatibility with the latest CMB constraints from Planck, BICEP/Keck, and BAO data. Specifically, we show that the scalar spectral index $$n_s$$ n s lies in the range 0.963–0.965, and the tensor-to-scalar ratio r is strongly suppressed, $$r \sim \mathscr {O}(10^{-3}$$ r ∼ O ( 10 - 3 – $$10^{-2})$$ 10 - 2 ) , for Higgs quartic couplings $$\lambda \sim 10^{-9}$$ λ ∼ 10 - 9 . These predictions remain robust under two distinct growing-mode functions. Furthermore, we show that the model is consistent with the refined de Sitter swampland conjecture due to entropy production during inflation. This work represents the first comprehensive study of warm minimal Higgs inflation in Palatini $$R^2$$ R 2 gravity, unifying quantum gravity criteria, thermal field dynamics, and observational consistency within a single inflationary framework.