Gauge-invariant quantum gravitational corrections to correlation functions

Oct 2, 2017
30 pages
Published in:
  • Class.Quant.Grav. 35 (2018) 5, 055006
  • Published: Feb 1, 2018
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Abstract: (IOP)
A recent proposal for gauge-invariant observables in inflation (Brunetti et al 2016 J. High Energy Phys. JHEP08(2016)032) is examined. We give a generalisation of their construction to general background spacetimes. In flat space, we calculate one-loop graviton corrections to a scalar two-point function in a general gauge for the graviton. We explicitely show how the gauge-dependent terms cancel between the usual self-energy contributions and the additional corrections inherent in these observables. The one-loop corrections have the expected functional form, contrary to another recently studied proposal for gauge-invariant observables (Fröb 2018 Class. Quantum Grav. 35 035005) where this is not the case. Furthermore, we determine the one-loop graviton corrections to the four-point coupling of the gauge-invariant scalar field, and the corresponding running of the coupling constant induced by graviton loops. Interestingly, the β function is negative for all values of the non-minimal coupling of the scalar field to curvature.
Note:
  • 34 pages, 1 figure, matches published version
  • perturbative quantum gravity
  • relational observables
  • renormalisation
  • invariance: gauge
  • gravitation: correction
  • field theory: scalar
  • quantum gravity: correction
  • two-point function: scalar
  • coupling: scalar
  • space-time: background