Some features of the extended phase space approach to quantization of gravity

Fuente: arXiv
Saved in:
Bibliographic Details
Main Author: Shestakova, T. P.
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866918102687547392
author Shestakova, T. P.
author_facet Shestakova, T. P.
contents In this paper, I emphasize those features of the extended phase space approach to quantization of gravity that distinguish it among other approaches. First of all, it is the conjecture about non-trivial topology of the Universe which was supported by Wheeler, Hawking and other founders of quantum gravity. However, this conjecture appears to be in contradiction with the assumption about asymptotic states that is used in the path integral quantization of gauge theories. The presence of asymptotic states ensures gauge invariance of the theory, but, in the case of gravity, the states exist only in asymptotically flat spacetimes, that limits possible topologies. Then we have two ways. The first way is to consider only asymptotically flat spacetimes. In fact, it reduces quantum gravity to quantum field theory on a given background. The second way is to reject the assumption about asymptotic states. In the case of non-trivial topology, one cannot cover the whole spacetime with the only coordinate system. One has to introduce various reference frames fixed by different gauge conditions in different spacetime regions. The Hamiltonian describing a gravitating system will depend on gauge conditions. It leads to the conclusion that unitary evolution may be broken down. This conclusion cannot be obtained in approaches based on the Wheeler - DeWitt equation or making use of the assumption about asymptotic states. The assessment of this conclusion is given.
format Preprint
id arxiv_https___arxiv_org_abs_2507_17371
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Some features of the extended phase space approach to quantization of gravity
Shestakova, T. P.
General Relativity and Quantum Cosmology
In this paper, I emphasize those features of the extended phase space approach to quantization of gravity that distinguish it among other approaches. First of all, it is the conjecture about non-trivial topology of the Universe which was supported by Wheeler, Hawking and other founders of quantum gravity. However, this conjecture appears to be in contradiction with the assumption about asymptotic states that is used in the path integral quantization of gauge theories. The presence of asymptotic states ensures gauge invariance of the theory, but, in the case of gravity, the states exist only in asymptotically flat spacetimes, that limits possible topologies. Then we have two ways. The first way is to consider only asymptotically flat spacetimes. In fact, it reduces quantum gravity to quantum field theory on a given background. The second way is to reject the assumption about asymptotic states. In the case of non-trivial topology, one cannot cover the whole spacetime with the only coordinate system. One has to introduce various reference frames fixed by different gauge conditions in different spacetime regions. The Hamiltonian describing a gravitating system will depend on gauge conditions. It leads to the conclusion that unitary evolution may be broken down. This conclusion cannot be obtained in approaches based on the Wheeler - DeWitt equation or making use of the assumption about asymptotic states. The assessment of this conclusion is given.
title Some features of the extended phase space approach to quantization of gravity
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2507.17371