Conformal gravity and a natural solution to the cosmological constant problem

Abstract

With attempts to quench the cosmological constant $Λ$ having so far failed, we instead investigate what could be done if $Λ$ is not quenched and actually gets to be as big as elementary particle physics suggests. Since the quantity relevant to cosmology is actually $Ω_Λ$, quenching it to its small measured value is equally achievable by quenching not $Λ$ but $G$ instead, with the $G$ relevant to cosmology then being much smaller than that measured in a low energy Cavendish experiment. A gravitational model in which this explicitly takes place, viz. conformal gravity, is presented, with the model being found to provide for a completely natural, non fine tuned accounting of the recent high $z$ accelerating universe supernovae data, no matter how big $Λ$ itself actually gets to be. Thus to solve the cosmological constant problem we do not need to change or quench the energy content of the universe, but rather only its effect on cosmic evolution.