Path integral and conformal instability in nonlocal quantum gravity

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.
Comment: 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