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

TL;DR

This paper explores gravitationally induced particle creation as a mechanism for late-time cosmic acceleration, constraining it with observational data and showing it can reduce the Hubble tension compared to standard cosmology.

Contribution

It introduces phenomenological models of particle creation that mimic dark energy and demonstrates their compatibility with observations, reducing the Hubble tension.

Findings

Particle creation models fit observational data as well as $\\Lambda$CDM.

Some models exhibit effective dynamical dark energy behavior.

Hubble tension is reduced to about 2.4-3 sigma with these models.

Abstract

The Hubble tension and the unknown origin of dark energy motivate the exploration of alternative mechanisms for late-time cosmic acceleration. We investigate gravitationally induced particle creation (PC) as a non-equilibrium process that can effectively mimic dynamical dark energy. Within the thermodynamic framework of open systems, we adopt an agnostic approach to the extra created component, leaving its equation-of-state parameter $w_E$ free. We consider four phenomenological parametrisations of the PC rate, allowing deviations from the standard cosmological model ($\Lambda$CDM) only at late times ($0<z<3$). The PC models are constrained using a joint analysis of cosmic chronometers, Type Ia supernovae, local $H_0$ measurements, baryon acoustic oscillations, and cosmic microwave background data. The constraints on $w_E$ are consistent with dark energy, while particle creation of pressureless matter is disfavoured. All PC scenarios provide fits comparable to $\Lambda$CDM, with one showing effective dynamical dark-energy behaviour. When early- and late-time datasets are analysed separately, the PC models reduce the Hubble tension to $\simeq 2.4\,\sigma$--$3\,\sigma$, compared to $4.3\,\sigma$ in $\Lambda$CDM. Gravitationally induced dark energy thus offers a consistent late-time extension of $\Lambda$CDM and a viable theoretical framework for dynamical dark energy.