Inflationary Cosmology in a non-minimal f (R, T) gravity theory using a RT mixing term

We investigate a class of inflationary models in modified gravity theories which contain a non-minimal coupling between gravity and a scalar field 41 as f (R, T) = R(1 + & alpha; + K4/3T) + K2 & gamma; T where K2 = 8nG where G is Newton's constant. We consider two inflaton potentials of the form (i) V = V0 (1 + ln 41) & lambda;41p and (ii) V0 1+& lambda;41p . For different potential parameters, we have explored the constraints on the modified gravity parameters i.e. (& alpha;, /3, and & gamma;) in the following three cases: (i) /3 = 0, & alpha; = & gamma; = 0, (ii) & alpha; = 0, & gamma; = 0, /3 = 0 and (iii) & gamma; = 0, & alpha; = 0, /3 = 0 for the above two potentials. We find that by the inclusion of RT mixing term, the scalar spectral index ns and tensor-to-scalar ratio r are consistent with the 3 & sigma; limit of the Planck data as well as r < 0.056. & COPY; 2023 Elsevier B.V. All rights reserved.

Automated summary

We investigate a class of inflationary models in modified gravity theories with non-minimal coupling between gravity and a scalar field. By considering different potential parameters, we find that the inclusion of the RT mixing term can lead to consistency between the scalar spectral index ns and tensor-to-scalar ratio r with the 3σ limit of the Planck data as well as r < 0.056.