String Cosmological Models in Alternative Theory of Gravity

Abstract

In the present communication, we have investigated Bianchi type-III string cosmological models in Brans-Dicke theory (BD) of gravity. For an exact solution of modified Einstein’s field equations (EFEs), we have considered that the deceleration parameter as a bilinear function of cosmic time as (1)()=(1)tqttα−+, hereαis a non-negative constant. It is analyzed from the study that the string tension density ()λis an increasing function of time whereas energy density()ρand cosmological constant()Λare decreasing with cosmic time and converges to a very small value at present epoh. Physical and geometrical behavior of various parameters have also been discussed.