Horndeski Genesis: Strong coupling and absence thereof

Abstract

We consider Genesis in Horndeski theory as alternative to or completion of inflationary scenario. One of the options free of instabilities at all comological epochs is putative strong coupling regime at the early Genesis stage. We address this issue to see whether classical field theory description of the background evolution at this early stage is consistent, nevertheless. We argue that, indeed, despite naive strong coupling, classical analysis is legitimate in a certain range of parameters. This opens up a posibility of a novel scenario for the beginning of the cosmological expansion.