Gauge-invariant quantum gravitational corrections to correlation functions

Understand

A recent proposal for gauge-invariant observables in inflation [R.

• Brunetti et al., JHEP 1608 (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.