Power law scalar potential in the Saez-Ballester like theory: Exact solutions in the Bianchi type I case

Abstract

We investigate exact anisotropic Bianchi type I cosmological solutions in a generalized S'aez--Ballester--K-essence-like theory containing two interacting scalar fields with quintessence, phantom, and mixed (quintom) kinetic sectors. The scalar-field self-interaction is described by inverse power-law potentials, which admit analytical solutions after an appropriate transformation of the field equations. The mixed kinetic interaction imposes nontrivial constraints on the model parameters, leading to six exact cosmological branches associated with the quintessence, phantom, and quintom scenarios. The exact solutions provide explicit expressions for the effective volume and scalar fields, allowing the reconstruction of the Hubble parameter, the deceleration parameter, and the effective equation-of-state parameter. Although the six branches exhibit distinct transient behaviors, all physically admissible solutions evolve toward the same asymptotic de Sitter attractor characterized by accelerated expansion. The analytical solutions reveal how the different kinetic sectors control the cosmological evolution while preserving a common late-time behavior. These results provide a unified analytical description of anisotropic cosmological dynamics in generalized scalar-field theories and may serve as a useful framework for investigating the role of interacting scalar fields in the early and late evolution of the Universe.