Truly Lorentzian quantum cosmology. III. Scalar field coupling

Description

Title: Truly Lorentzian quantum cosmology. III. Scalar field coupling

Author: Ding Jia

Abstract: In prequel works we compared real time path integrals for minisuperspace quantum cosmology with and without a Lorentzian constraint. It was found that restricting the sum to metrics of the Lorentzian signature gives rise to new stationary paths for the action. These paths indicate how the effective geometries of the quantum model continue through the cosmological singularity by bouncing once off the singularity. In the present work, we improve the pure gravity model by matter coupling. For a scalar field with hyperbolic potentials, the Lorentzian constraint again gives rise to new stationary paths. As a novelty, the effective geometries now bounce twice off the singularity instead of once in the case of pure gravity. A computation of their semiclassical weights shows that the new effective geometries make significant contributions to the path integral. Therefore scalar field coupling induces multiple bounce effective geometries in Lorentzian quantum cosmology.

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Version history

• Original versions: Article v1.0; Notebook v1.0
• Article v1.1 and Notebook v1.1: minor updates to improve presentation and correct typos