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The Isaacson expansion in quantum cosmology

Carsten Gundlach
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Abstract

This paper is an application of the ideas of the Born-Oppenheimer (or slow/fast) approximation in molecular physics and of the Isaacson (or short-wave) approximation in classical gravity to the canonical quantization of a perturbed minisuperspace model of the kind examined by Halliwell and Hawking. Its aim is the clarification of the role of the semiclassical approximation and the backreaction in such a model. Approximate solutions of the quantum model are constructed which are not semiclassical, and semiclassical solutions in which the quantum perturbations are highly excited.

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Carsten Gundlach. 1993-04-08. The Isaacson expansion in quantum cosmology. https://doi.org/10.1103/physrevd.48.1700

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