Influence on Observation from IR Divergence during Inflation. II : Multi-Field Inflation(Astrophysics and Cosmology)

概要

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We propose a way to regularize the fluctuations generated during inflation, whose infrared (IR) corrections diverge logarithmically. In the case of a single-field inflation model, recently, we have proposed a solution to the IR divergence problem. There, we introduced new perturbative variables that better mimic actual observable fluctuations, and proved the regularity of correlation functions with respect to these variables. In this paper, we extend our previous discussions to a multi-field inflation model. We show that, as long as we consider the case that the nonlinear interaction acts for a finite duration, observable fluctuations are also free from IR divergences in the multi-field model. In contrast to the single-field model, to discuss observables, we need to take into account the effects of quantum decoherence, which pick up a unique history of the universe from various possibilities contained in an initial quantum state set naturally in the early stage of the universe.
理論物理学刊行会の論文
2009-11-25