2025/02/25 by Sengupta, Sandipan
#FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.2502.18585
We develop a Lagrangian formulation for gravity with matter where the gravitational couplings are universally treated as being field-dependent. The solutions for FLRW geometries and the associated time evolution of the Newton and cosmological couplings are found. The distance-redshift relations are shown to prefer a slowly growing Newton's coupling along with a negative equation of state (w≥ -(1)/(3)) for the matter fluid at the present epoch of accelerated expansion, while ruling out Dirac's large number hypothesis. We obtain an improved bound on G(t) as: 1.67× 10-11 yr-1<\fracGG<3.34× 10-11 yr-1 in the context of supernova cosmology, as well as a new constraint on Λ(t) as: -0.67× 10-11 yr-1<\fracΛΛ<-1.34× 10-11 yr-1. Based on this formulation, we also present a dynamical solution to the `cosmic coincidence' problem.