Revisiting the Matter Creation Process: Observational Constraints on Gravitationally Induced Dark Energy and the Hubble Tension

Abstract: The persistent Hubble tension and the lack of a fundamental explanation for dark energy motivate the exploration of alternative mechanisms capable of reproducing late-time cosmic acceleration. In this work, we revisit gravitationally induced particle creation as a phenomenological non-equilibrium process that can effectively mimic a dynamical dark-energy component. Within the thermodynamic framework of open systems, we model the production of an unspecified particle species with constant intrinsic equation-of-state parameter and consider four phenomenological parametrisations of the particle-creation rate. The modified continuity and Friedmann equations lead to an effective negative pressure and a redshift-dependent effective equation of state, which we constrain using Cosmic Chronometers, Pantheon+ supernovae, DESI DR2 BAO, a compressed CMB likelihood, and SH0ES data. Using the full dataset combination, we find that particle-creation models provide fits comparable to $Λ$CDM, yielding $H_0 \simeq 69.3\,\mathrm{km\,s^{-1}\,Mpc^{-1}}$ and present-day effective dark-energy equation-of-state values close to $w^{\rm eff}_{\rm DE}(0)\simeq -1$, with all models predicting an accelerating Universe ($q_0\simeq -0.55$). When the Hubble tension is assessed using early- and late-time dataset splits, particle-creation scenarios reduce its statistical significance to the $\simeq 2.4σ$--$3σ$ level, compared to the $4.3σ$ discrepancy obtained in $Λ$CDM. Although deviations from $Λ$CDM remain mild and Bayesian model comparison indicates no statistical preference between models, gravitationally induced particle creation emerges as a viable late-time extension of the standard cosmological model and provides a consistent phenomenological framework for exploring departures from $Λ$CDM.