Consistency issue for anisotropic quantum cosmology?

Description

Title: Consistency issue for anisotropic quantum cosmology?

Author: Ding Jia

Abstract: In a series of recent works, Feldbrugge, Lehners, and Turok (FLT) challenged the consistency of no-boundary/tunnelling-type boundary conditions applied to real time path integrals for quantum cosmology. Specifically, for the anisotropic Biaxial Bianchi IX model with vanishing initial squared scale factors, FLT reach the conclusion that the model suffers issues of anisotropic instability and non-normalizability. This conclusion rests on an assumption that, for all values of the lapse N, a fixed saddle of the squared scaled factor p is relevant. Here we argue that this assumption is invalid, because for small values of N, the Morse function for the purported saddle in p has a larger value than on the original contour. Picard-Lefschetz theory then rules out the possibility that this saddle is relevant for small N. A more careful analysis of the relevant saddles shows that the purported issues cannot be maintained.

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• Original versions: Article v1.0; Notebook v1.0