Oscillatory Phase of Nonclassical Thermal Inflaton in FRW Universe

Abstract

A minimally coupled nonclassical homogeneous scalar field is examined in the flat FRW universe in the semiclassical theory of gravity. Particle production in thermal coherent and squeezed states is studied for the flat FRW universe, in the oscillatory phase of the inflaton. Solutions for the semiclassical Friedmann equations are obtained in the thermal nonclassical states. Validity of the semiclassical theory is examined in the thermal coherent and squeezed states in the oscillatory phase of inflaton. Particle creation can be enhanced due to thermal and quantum effects. Quantum fluctuations of the inflaton in thermal coherent and squeezed state formalisms are also studied. Classical gravity differ from semiclassical gravity in the thermal coherent state only by an amplitude factor.

B Mode Correlation Enhancement of CMB From Thermal Squeezed Vacuum State

“…The squeezed states and its thermal counter parts are used to study the particle creation in the early universe. [35][36][37][38][39] An effective approach to deal with these states is the thermofield dynamics (TFD). [40][41][42][43][44][45] In this approach the expectation value of mixed state at nonzero temperature is obtained by an equivalent computation with a pure state.…”

Squeezed Thermal State Representation of the Inflaton and Particle Production in Bianchi type-I Universe

“…Thermal counterparts of coherent and squeezed states are recognized as a coherent thermal state [49][50][51][52][53][54] and squeezed thermal state [50,51,[55][56][57][58]. Thermal properties of the nonclassical states play an important role to understand the thermal history and evolution of the early-stage universe [59][60][61][62][63][64][65]. According to cosmological perspective, consideration of thermal effects in flat FRW universe has many significance.…”