  In this paper it is suggested that inclusion of mutual gravitational
interactions among the particles in the early dense universe can lead to a
'pre-big bang' scenario, with particle masses greater than the Planck mass
implying an accelerating phase of the universe, which then goes into the
radiation phase when the masses fall below the Planck mass. The existence of
towers of states of such massive particles (i.e. multiples of Planck mass) as
implied in various unified theories, provides rapid acceleration in the early
universe, similar to the usual inflation scenario, but here the expansion rate
goes over 'smoothly' to the radiation dominated universe when temperature
becomes lower than the Planck temperature.
