Particle production and density fluctuations of nonclassical inflaton in coherent squeezed vacuum state of flat FRW universe.

In this paper, we study nonclassical inflaton, which is minimally coupled to the semi-classical gravity in FRW universe in Coherent Squeezed Vacuum State (CSVS). We have determined the Oscillatory phase of inflaton, power-law expansion, scale factor, density fluctuations, quantum fluctuations and particle production for CSVS. We have obtained an estimated leading solution of scale factor in CSVS and found it proportional to t2/3 and showing similar diversification as demonstrated by Semi-classical Einstein Equation (SCEE) of gravity in matter dominated universe. We have also studied the validity of SCEE in CSVS. We have computed validity of uncertainty relation for FRW Universe by determining the quantum fluctuation for CSVS. Our results show that Quantum fluctuations don’t depend on coherent parameter ϒ as the uncertainty relation doesn’t effect by the displacement of ϒ in phase space. We have also studied the production of particles in CSVS for oscillating massive inflaton in flat FRW universe. [ABSTRACT FROM AUTHOR]