Opening Pandora's box: Kundt solutions to Conformal Killing Gravity

Abstract: We consider Kundt solutions to vacuum Conformal Killing Gravity (CKG) proposed by Harada and find numerous solutions in four dimensions and in higher dimensions. In CKG theory the cosmological constant appears as an integration constant, and hence, is naturally embedded in the theory. However, by considering Kundt solutions to CKG we seemingly open Pandora's box: We find so many solutions so a selection criterium is needed in CKG to explain the current accelerated expansion of the universe.