Kaluza-Klein Cosmology with Varying G and $\Lambda$

Abstract

In this paper we investigate non-compact FRW type Kaluza-Klein cosmology coupled with 5D energy-momentum tensor. The field equations are solved by taking gravitational and cosmological constants as a function of time $t$. We use $\Lambda(t)=\epsilon H^{2}$ to explore cosmological parameters including statefinder and discuss them for dust, radiation and stiff matter dominated eras. Also, we evaluate lookback time, proper distance, luminosity distance and angular diameter distance. We obtain a universe which is not compatible with current cosmological observations at $\epsilon=6$. However, for $\epsilon>6$, the results are compatible with observational cosmology.