Cosmic expansion driven by gravitational particle production: toward a complete cosmological scenario

Abstract A dark-energy-free cosmological model $$(\Omega _{DE} \equiv 0)$$ ( Ω DE ≡ 0 ) based on gravitationally induced adiabatic particle creation is proposed. The thermodynamics of particle production yields an effective negative pressure that drives both primordial inflation and late-time cosmic acceleration. The model, characterized by four components and two free parameters $$(\alpha ,$$ ( α , $$\beta )$$ β ) , reproduces a $$\Lambda $$ Λ CDM-like expansion for suitable $$\alpha ,$$ α , while $$\beta $$ β introduces small but testable deviations from the cosmic concordance model. Constraints from type Ia Supernovae (Pantheon+SH0ES) and H ( z ) data indicate $$\beta \simeq 0.13,$$ β ≃ 0.13 , suggesting a mild departure from standard cosmology and possible relief of the $$H_0$$ H 0 and $$S_8$$ S 8 tensions. The resulting classical cosmology evolves smoothly between two extreme de Sitter phases, offering a singularity-free, unified scenario that beyond solving old cosmological puzzles opens a new perspective to handle the tensions plaguing the current cosmic concordance model.