Quantum creation and inflationary universes: A critical appraisal

D. H. Coule
2000 Physical Review D, Particles and fields  
We contrast the possibility of inflation starting a) from the universe's inception or b) from an earlier non-inflationary state. Neither case is ideal since a) assumes quantum mechanical reasoning is straightforwardly applicable to the early universe; while case b) requires that a singularity still be present. Further, in agreement with Vachaspati and Trodden [1] case b) can only solve the horizon problem if the non-inflationary phase has equation of state γ<4/3.
doi:10.1103/physrevd.62.124010 fatcat:e2dgctajprh7rpgm4nayi7iliy