Comment on "Cosmological inviability of $f(R,T)$ gravity"

TL;DR

This paper refutes claims that a previous $f(R,T)$ gravity model cannot produce the universe's transition from deceleration to acceleration, demonstrating that the earlier results remain valid and that the recent critique was based on mathematical errors.

Contribution

The authors clarify and correct the mathematical approach in the critique, reaffirming the validity of the original $f(R,T)$ gravity model's predictions about cosmic acceleration.

Findings

The critique's calculations are mathematically incorrect.

The original model's prediction of cosmic transition remains valid.

The recent critique's solutions are mathematically unfeasible.

Abstract

The recent article entitled "Cosmological inviability of $f(R,T)$ gravity" [Phys. Rev. D 95 (2017) 123536], by H. Velten and T.R.P. Caram\^es, claims that the reference "A transition from a decelerated to an accelerated phase of the universe expansion from the simplest non-trivial polynomial function of T in the f(R,T) formalism" by P.H.R.S. Moraes, G. Ribeiro and R.A.C. Correa [Astrophys. Space Sci. 361 (2016) 227] has "problematic points" concerning its mathematical approach and observable consequences. Velten and Caram\^es argue that the equation of the scale factor evolution in time in the $f(R,T)=R+\alpha T+\beta T^{2}$ cosmology was erroneously calculated. One crucial consequence of the supposed corrected version of such an equation, presented by the authors in [Phys. Rev. D 95 (2017) 123536], would be the absence of the transition from a decelerated to an accelerated phase of the expansion of the universe, an outcome originally predicted by Moraes, Ribeiro and Correa. We show that the above claim is incorrect and that there are no inconsistencies with the results by Moraes, Ribeiro and Correa in the referred work. In particular, we show that Velten and Caram\^es have incorrectly performed their calculations, invalidating all their mathematical and physical criticism regarding the article by Moraes, Ribeiro and Correa. In addition, we quote that the solutions obtained by Velten and Caram\^es are unfeasible in view of their mathematical misunderstanding.