Quantum Gravity and the Correspondence Principle

TL;DR

This paper questions the assumption that quantum gravity theories must recover general relativity at low energies, highlighting potential discontinuities in physical fields that could alter spacetime structure.

Contribution

It challenges the conventional view that quantum gravity smoothly transitions to general relativity, proposing that discontinuities may prevent this and alter low-energy spacetime behavior.

Findings

Discontinuities in physical fields can change spacetime structure.

Low energy limit of quantum gravity may differ from general relativity.

Assumption of smooth transition in quantum gravity theories is questioned.

Abstract

Standard approaches to quantum gravity start with a pre-spacetime structure and attempt, in accordance with Bohr's correspondence principle, to recover the pseudo-Riemannian manifold in the low energy limit. These approaches assume there is a smooth transition from quantum gravity to general relativity common to successful quantum theories. However, as gravitational field, and hence spacetime, cannot be considered in isolation from physical fields, discontinuities in properties of physical fields, such as loss of mass at the electroweak symmetry breaking scale, may result in change of spacetime structure somewhere between the Planck scale and the scale where general relativity holds true. As a result, the correct theory of quantum gravity may not have general relativity as its low energy limit.