String Viscous Fluid Cosmological Model in the Framework of Sen-Dunn Theory of Gravitation

Objective: To present a new solution to the field equations for higher-dimensional Bianchi type-III string viscous fluid cosmological model in the context of the Sen-Dunn theory of gravity. Methods: To obtain definite solution of the field equations, we consider a power law relation between the scale factor and scalar field, and we take into account two distinct scale factors, and , in which , are positive constants. This produces a time-dependent deceleration parameter. We analyse the model with constant bulk viscosity constant to explain the current accelerated expansion of the universe. Findings: Spatial volume of the model increases with cosmic time, which shows that universe is spatially expanding. Also, the model possesses a point-type singularity. It is noted that these models depict the universe's accelerated expansion. Novelty: We obtained new solution to the field equations for higher dimensional Bianchi type-III generated by means of a cloud of strings with bulk viscous fluid in Sen-Dunn theory by using quadratic form. Keywords: Bianchi type-III, Cosmic string, Bulk viscosity, Sen-Dunn Theory