article · Monthly Notices of the Royal Astronomical Society
This research examines observational constraints on the scalar-tensor representation of f(R, T) gravity within an open thermodynamic framework allowing matter creation and annihilation. Using observational data from Hubble parameter and Pantheon+ supernova measurements, two cosmological models with differing potentials were analysed through numerical solutions of modified Friedmann equations and Markov Chain Monte Carlo simulations. The study derived cosmographic parameters, including deceleration, jerk, and snap, alongside matter creation rates and pressures. Statistical comparisons using the corrected Akaike information criterion showed that the first model is statistically favoured over the standard cosmological constant cold dark matter model. The first model displays continuous particle creation, whereas the second exhibits negative creation rates at high redshifts, corresponding to particle annihilation. Both models successfully account for the late-time accelerated expansion of the universe, matching the deceleration behaviour found in standard cosmology.
Understanding whether alternative theories of gravity can describe cosmic expansion better than standard models helps scientists resolve fundamental questions about the universe. By evaluating models that incorporate the spontaneous creation or annihilation of particles against actual astronomical observations, this work clarifies whether modified gravity can offer a statistically viable explanation for the accelerating expansion of the cosmos.
The abstract does not indicate an application pathway or any commercial use, as the research is focused entirely on theoretical cosmology and observational tests of gravitational models.
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ABSTRACT Recently, the scalar–tensor representation of f(R, T) gravity was used to explore gravitationally induced particle production/annihilation. Using the framework of irreversible thermodynamics of open systems in the presence of matter creation/annihilation, the physical and cosmological consequences of this setup were investigated in detail. In this paper, we test observationally the scalar–tensor representation of f(R, T) gravity in the context of the aforementioned framework, using the Hubble and Pantheon + measurements. The best fit parameters are obtained by solving numerically the modified Friedmann equations of two distinct cosmological models in scalar–tensor f(R, T) gravity, corresponding to two different choices of the potential, and by performing a Markov Chain Monte Carlo analysis. The best parameters are used to compute the cosmographic parameters, that is, the deceleration, the jerk, and the snap parameters. Using the output resulting from the Markov Chain Monte Carlo analysis, the cosmological evolution of the creation pressure and of the matter creation rates are presented for both models. To figure out the statistical significance of the studied scalar–tensor f(R, T) gravity, the Bayesian and the corrected Akaike information criteria are used. The latter indicates that the first considered model in scalar–tensor f(R, T) gravity is statistically better than ΛCDM, that is, it is more favoured by observations. Besides, a continuous particle creation process is present in Model 1. Alternatively, for large redshifts, in Model 2 the particle creation rate may become negative, thus indicating the presence of particle annihilation processes. However, both models lead to an accelerating expansion of the universe at late times, with a deceleration parameter equivalent to that of the ΛCDM model.
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DOI: 10.1093/mnras/stad2998
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