Constant-roll inflation in f(T) teleparallel gravity

Abstract

We investigate in detail the implications of the constant-roll condition on the inflationary era of a scalar field coupled to a teleparallel f(T) gravity. The resulting cosmological equations constitute a reconstruction technique which enables us to find either the f(T) gravity which corresponds to a given cosmological evolution, or the Hubble rate of the cosmological evolution generated by a fixed f(T) gravity. We also analyze in some detail the phase space of the constant-roll teleparallel gravity and we discuss the physical significance of the resulting fixed points and trajectories. Also we calculate the observational indices of a theory with given f(T) gravity, and we discuss all the implications of the constant-roll condition on these. As we demonstrate, the resulting theory can be compatible with the current observational data, for a wide range of values of the free parameters of the theory.