http://arxiv.org/abs/1503.04698
Based on the quantum effective action we compute for interacting theories the time evolution of correlation functions in inflationary cosmology. We neglect non-linearities due to backreaction, an explicit space-time dependence of the effective action reflecting boundary effects, and higher than second time derivatives. In this approximation the information about the state of the universe at the beginning of inflation remains imprinted on the observable primordial fluctuation spectrum. We therefore observe the initial spectrum, processed only mildly by the scale-violating effects at horizon crossing induced by the inflaton potential. Depending on initial conditions the relation between amplitude and Hubble parameter at the time of horizon crossing or the spectral index can be modified. Observations of the cosmic microwave background can gain information on the inflaton potential only if either the omitted non-linear effects lead to a fast enough symmetrization and dissipation of the initial spectrum, or if the initial spectrum can be constrained. The latter may be realized if inflation lasts sufficiently long before the time of horizon crossing and the ultraviolet behavior of correlation functions is the same as for flat space.
C. Wetterich
Tue, 17 Mar 15
40/79
Comments: 5 pages
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