Slow-roll inflation in the f(φ,T) gravity theory

In this paper, we study inflation in a modified gravity framework by introducing a direct coupling term between a scalar field [Formula: see text] (inflaton) and the trace of the energy–momentum tensor [Formula: see text] as [Formula: see text] to the Einstein–Hilbert action. We consider two inflaton potentials (i) [Formula: see text], (ii) [Formula: see text] and investigate the sensitivity of the modified gravity parameters [Formula: see text] and [Formula: see text] on the inflaton dynamics in the parameter space [Formula: see text] of the inflaton potentials. We derive the potential slow-roll parameters, scalar spectral index [Formula: see text], and tensor-to-scalar ratio [Formula: see text] in the above [Formula: see text] gravity theory and analyze the following three choices of modified gravity parameters [Formula: see text] (i) Case I: [Formula: see text] i.e. we neglect the higher order [Formula: see text] term in the analysis, (ii) Case II: [Formula: see text], [Formula: see text] and do the analysis with only [Formula: see text] term, (iii) Case III: [Formula: see text] and [Formula: see text] i.e. keeping both [Formula: see text] and [Formula: see text] terms. For a range of potential parameters, we obtain constraints on [Formula: see text] and [Formula: see text] in each of the above three cases using the PLANCK 2018 data. In both Cases I and III, we found that both the potentials were capable of predicting the value of [Formula: see text] within a range of [Formula: see text] of the Planck 2018 data, while simultaneously satisfying the constraint [Formula: see text]. In Case II, we observe that the scalar-to-tensor ratio is rather high however it can still predict the scalar spectral index within the range of Planck 2018 data.