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arXiv · hep-th/0310265

Back Reaction Of Perturbations In Two Scalar Field Inflationary Models

Ghazal Geshnizjani·Robert Brandenberger
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Abstract

We calculate the back-reaction of long wavelength cosmological perturbations on a general relativistic measure of the local expansion rate of the Universe. Specifically, we consider a cosmological model in which matter is described by two scalar matter fields, one being the inflaton and the other one representing a matter field which is used as a clock. We analyze back-reaction in a phase of inflaton-driven slow-roll inflation, and find that the leading infrared back-reaction terms contributing to the evolution of the expansion rate do not vanish when measured at a fixed value of the clock field. We also analyze the back-reaction of entropy modes in a specific cosmological model with negative square mass for the entropy field and find that back-reaction can become significant. Our work provides evidence that, in general, the back-reaction of infrared fluctuations could be locally observable.

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Ghazal Geshnizjani, Robert Brandenberger. 2003-10-29. Back Reaction Of Perturbations In Two Scalar Field Inflationary Models. https://doi.org/10.1088/1475-7516%2F2005%2F04%2F006

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