- #1
- 15,168
- 3,374
It's often said that gauge invariant local observables in quantum gravity must be relational. In classical gravity, relational observables are constructed with matter. LQG for the most part has not had matter, yet it has been said to have observables such as area or volume. Are these non-local, or not gauge invariant? There have also been attempts to incorparate matter in LQG. Do these have gauge invariant local observables?