Path integral and conformal instability in nonlocal quantum gravity

Abstract

We introduce the Lorentzian path integral of nonlocal quantum gravity. After introducing the functional measure, the Faddeev-Popov sector and the field correlators, we move to perturbation theory and describe Efimov analytic continuation of scattering amplitudes to Euclidean momenta and back to Lorentzian. We show that the conformal instability problem in the Euclidean path integral is solved by suitable gauge choices at the perturbative level. The three examples of Einstein gravity, Stelle gravity and nonlocal quantum gravity are given.

1+27 pages. v2: sections 2.3, 2.5 and 4 revised and expanded, Efimov analytic continuation and relation between Lorentzian and Euclidean path integrals clarified, conclusions on conformal instability strengthened (section 5), references added

References in corpus (5)

• Nonperturbative Quantum Gravity
• A Short Review of Loop Quantum Gravity
• Fakeons and the classicization of quantum gravity: the FLRW metric
• Renormalizability of nonlocal quantum gravity coupled to matter
• Spinfoams: Foundations

Cited by in corpus (4)

• Representations of the fractional d'Alembertian and initial conditions in fractional dynamics
• On the Meaning of Localization in Non-Local Quantum Field Theory and On the Limits of a Space-Time Description and the Physical Meaning of Phase Space in a Nonlocal Continuum
• Cosmology of fractional gravity
• Hawking area law in quantum gravity