The operational meaning of total energy in general relativity
Simone Speziale - Aix-Marseille University
Dowker, F. (2025). What are the `axioms’ of General Relativity? Ask Quantum Gravity!. Perimeter Institute. https://pirsa.org/25100108
Dowker, Fay. What are the `axioms’ of General Relativity? Ask Quantum Gravity!. Perimeter Institute, Oct. 02, 2025, https://pirsa.org/25100108
@misc{ pirsa_PIRSA:25100108,
doi = {10.48660/25100108},
url = {https://pirsa.org/25100108},
author = {Dowker, Fay},
keywords = {Quantum Gravity},
language = {en},
title = {What are the {\textquoteleft}axioms{\textquoteright} of General Relativity? Ask Quantum Gravity!},
publisher = {Perimeter Institute},
year = {2025},
month = {oct},
note = {PIRSA:25100108 see, \url{https://pirsa.org}}
}
The good books on GR agree on certain aspects of the theory that we could consider to be its “core” features. Beyond the core, however, we do not know exactly what GR should allow or not allow physically. For example, should we consider spacetimes with closed causal loops as part of physical GR or not? Are spacetimes with certain types of boundaries or singularities part of GR? Most people expect that the answer to these sorts of questions will be answered by quantum gravity when we have it. We can start to address them within different quantum gravity approaches even at their current partial state of their development. Within the framework of the path integral for quantum gravity and a Feynmanian heuristic for the recovery of the classical approximation, I will sketch out how answers may arise. I will use the example of causal set quantum gravity but I suggest that the ideas are applicable to other path integral approaches.