  We study non-classical inflaton, which is minimally coupled to the
semiclassical gravity in FRW universe in Coherent Squeezed Vacuum State (CSVS).
We determined Oscillatory phase of inflaton, power-law expansion, scale factor,
density fluctuations, quantum fluctuations and particle production for CSVS. We
obtained an estimated leading solution of scale factor in CSVS proportional to
$t^{2/3}$ follow similar diversification as demonstrated by Semiclassical
Einstein Equation (SCEE) of gravity in matter dominated universe. We also
studied the validity of SCEE in CSVS. By determining the quantum fluctuation
for CSVS validity of uncertainty relation for FRW Universe also computed. The
results shows that Quantum fluctuations doesn't depend on coherent parameter
$\Upsilon$ as uncertainty relation doesn't effected by the displacement of
$\Upsilon$ in phase space. We study the production of particles in CSVS for
oscillating massive inflaton in flat FRW universe.
