Finslerian warm inflation: Dynamics and observational signatures

This paper studies the warm inflationary scenario within the framework of a Finslerian model of the Universe based on Finsler–Barthel–Randers geometry. Finsler geometry is a natural generalization of Riemannian geometry in which the spacetime structure depends not only on position but also on direction in the tangent bundle. We derive the modified slow-roll conditions and analyze the inflationary dynamics in both weak and strong dissipative regimes for power-law inflaton potentials and dissipation coefficients. Explicit expressions for the scalar spectral index and the tensor-to-scalar ratio are obtained, exhibiting a direct dependence on the Finslerian parameters that control the evolution of spacetime anisotropy. More importantly, we show that the combined effects of thermal dissipation and Finslerian anisotropy naturally suppress the tensor-to-scalar ratio, resulting in improved compatibility with current Cosmic Microwave Background observations. Finally, we confront the theoretical predictions with the Planck 2018 + BICEP/Keck constraints on the scalar spectral index and tensor-to-scalar ratio.