Single scale factor for the universe from the creation of radiation and   matter till the present
  A scheme for incorporating the creation of radiation and matter into the cosmological evolution is introduced so that it becomes possible to merge the times before and after the creation of radiation and matter in a single scale factor in Robertson-Walker metric. This scheme is illustrated through a toy model that has the prospect of constituting a basis for a realistic model. 
Recai Erdem
gr-qc astro-ph.CO hep-ph hep-th