Large Scale Quantum Fluctuations in the Inflationary Universe

Abstract

Quantum fluctuations of an inflationdriving scalar field are evaluated in a way manifestly iridependent of the choice of coordinate gauge conditions. It is found that the dynamical degree of freedom of the fluctuating field is represented in terms of a nearly massless conformal scalar field in the unperturbed de Sitter background. Implications of the result are discussed. In particular, it is argued that classical cosmological density perturbations may not be generated in the sense as discussed in the literature.