Reconstructing the graviton

Understand

We reconstruct the Lorentzian graviton propagator in asymptotically safe quantum gravity from Euclidean data.

• The reconstruction is applied to both the dynamical fluctuation graviton and the background graviton propagator.
• We prove that the spectral function of the latter necessarily has negative parts similar to, and for the same reasons, as the gluon spectral function.
• In turn, the spectral function of the dynamical graviton is positive.