Complex Scalar fields in Scalar-Tensor and Scalar-Torsion theories

Understand

We investigate the cosmological dynamics in a spatially flat Friedmann--Lema\^{\i}tre--Robertson--Walker geometry in scalar-tensor and scalar-torsion theories where the nonminimally coupled scalar field is a complex field.

• We derive the cosmological field equations and we make use of dimensionless variables in order to determine the stationary points and determine their stability properties.
• The physical properties of the stationary points are discussed while we find that the two-different theories, scalar-tensor and scalar-torsion theories, share many common features in terms of the evolution of the physical variables in the background space.