Standard Cosmology Delayed
  The introduction of a delay in the Friedmann equation of cosmological evolution is shown to result in the very early universe undergoing the necessary accelerated expansion in the usual radiation (or matter) dominated phase. Occurring even without a violation of the strong energy condition, this expansion slows down naturally to go over to the decelerated phase, namely the standard Hubble expansion. This may obviate the need for a scalar field driven inflationary epoch. 
Debajyoti Choudhury, Debashis Ghoshal and Anjan Ananda Sen
gr-qc astro-ph.CO hep-ph hep-th