English

What is "quantum" about quantum gravity?

Quantum Physics 2025-01-13 v2 General Relativity and Quantum Cosmology High Energy Physics - Theory

Abstract

Assuming the validity of the equivalence principle in the quantum regime, we argue that one of the assumptions of the usual definition of quantum mechanics, namely separation between the ``classical'' detector and the ``quantum'' system, must be relaxed. We argue, therefore, that if both the equivalence principle and quantum mechanics continue to survive experimental tests, that this favors ``epistemic'' interpretations of quantum mechanics (where formalism is built around relations between observables) over ``ontic ones'' (assuming the reality of states and wavefunctions). In particular, we show that relational type interpretations can readily accomodate the equivalence principle via a minor modification of the assumptions used to justify the formalism. We qualitatively speculate what a full generally covariant quantum dynamics could look like, and comment on experimental investigations.

Keywords

Cite

@article{arxiv.2405.08192,
  title  = {What is "quantum" about quantum gravity?},
  author = {Giorgio Torrieri},
  journal= {arXiv preprint arXiv:2405.08192},
  year   = {2025}
}

Comments

Version accepted for publication, International Journal of Modern Physics D

R2 v1 2026-06-28T16:26:06.637Z