Manuel Reichert (Sussex U.), Spectral functions in quantum gravity and gauge theories

Tuesday 13 Dec 2022, 14:00 → 15:30 Europe/Stockholm

Albano 3: 6228 - Mega (22 seats) (Albano Building 3)

Over the past decades, the asymptotic safety scenario has matured into a viable contender for a consistent theory of quantum gravity. In particular, the predictivity and the connection to the Standard Model have been very successfully explored. One pressing open question is the unitarity of the theory, which requires an understanding on Lorentzian backgrounds and the computation of correlation functions for time-like momenta. Spectral functions are an important tool in this context since they fully describe propagators and encode aspects of the unitarity of the theory. The application of spectral functions to gauge fields bears some unexpected intricacies which I will elucidate at perturbatively controlled models such as QCD with a Banks-Zaks fixed point and the Litim-Sannino model. I will then bridge the gap to non-perturbative asymptotically safe gravity and show the results of the first direct computation of the graviton spectral function.