https://doi.org/10.1140/epjc/s10052-024-12544-9
Regular Article - Theoretical Physics
Search for the f(R, T) gravity functional form via gaussian processes
1
Centro de Ciências Exatas, Departamento de Física, PPGCosmo, Universidade Federal do Espírito Santo (UFES), Avenida Fernando Ferrari 514, 29075-910, Vitória, ES, Brazil
2
Laboratório de Física Teórica e Computacional (LFTC), Universidade Cidade de São Paulo (UNICID), Rua Galvão Bueno 868, 01506-000, São Paulo, Brazil
3
Instituto de Física, Universidade Federal do Alagoas (UFAL), Avenida Lourival Melo Mota S/N, 57072-970, Maceió, AL, Brazil
4
Centro de Ciências Exatas e das Tecnologias, Universidade Federal do Oeste da Bahia, Rua Bertioga 892, 47810-059, Barreiras, BA, Brazil
a
jeferson.fortunato@edu.ufes.br
Received:
13
October
2023
Accepted:
11
February
2024
Published online:
26
February
2024
The f(R, T) gravity models, for which R is the Ricci scalar and T is the trace of the energy–momentum tensor, elevate the degrees of freedom of the renowned f(R) theories, by making the Einstein field equations of the theory to also depend on T. While such a dependence can be motivated by quantum effects, the existence of imperfect or extra fluids, or even a cosmological “constant” which effectively depends on T, the formalism can truly surpass some deficiencies of f(R) gravity. As the f(R, T) function is arbitrary, several parametric models have been proposed ad hoc in the literature and posteriorly confronted with observational data. In the present article, we use gaussian process to construct an 
model. To apply the gaussian process we use a series of measurements of the Hubble parameter. We then analytically obtain the functional form of the function. By construction, this form, which is novel in the literature, is well-adjusted to cosmological data. In addition, by extrapolating our reconstruction to redshift 
, we were able to constrain the Hubble constant value to 
with 
precision. Lastly, we encourage the application of the functional form herewith obtained to other current problems of observational cosmology and astrophysics, such as the rotation curves of galaxies.
Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjc/s10052-024-12544-9.
© The Author(s) 2024
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