A Gauss-Bonnet theory of gravitation with torsion and electromagnetic fields

This study focuses on the cosmological characteristics of a flat universe containing an electromagnetic field. By incorporating Gauss-Bonnet gravitational corrections, it analyzes the kinematic equations based on torsion cosmology and modifies the gauge field equations. This leads to the fundamental equations and gravitational properties of flat universe inflation. The addition of the correction terms facilitates the study of the low-energy limit of string theory, making the difficult-to-observe effects of string theory potentially observable. Gauss-Bonnet theory, with its advantage of requiring no extra fundamental fields, modifies the gravitational theory based on General Relativity (GR) and ensures no dynamical effects in four dimensions under the low-energy effective action of string theory. Considering the SU(2) gauge model, a renormalizable Lagrangian is obtained. By modifying the supersymmetric hybrid inflation model with GB terms, the study derives the modified field equations for gauge bosons and the matter field in torsion gauge field GB theory. It also examines the impact of GB terms on the Hubble constant, suggesting observable effects of low-energy string theory. Under the ?^n gravity model and DeFelice-Tsujikawa model, the study further assesses the sensitivity of the GB term coupling parameters to the model, exploring the potential for observational verification.