Reconstructing the graviton

@article{Bonanno2021ReconstructingTG,
  title={Reconstructing the graviton},
  author={Alfio Bonanno and Tobias Denz and Jan M. Pawlowski and Manuel Reichert},
  journal={SciPost Physics},
  year={2021}
}
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. We argue that the latter enters cross sections and… 

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