Quantum reference frames for spacetime symmetries and large gauge transformations
Abstract
Symmetries are a central concept in our understanding of physics. In quantum theories, a quantum reference frame (QRF) can be used to distinguish between observables related by a symmetry. The framework of operational QRFs provides a means to describe observables in terms of their relation to a reference quantum system. We discuss a number of applications of QRFs in the context of quantum field theory on curved spacetimes: 1) A type reduction result for algebras arising from QFTs and QRFs with good thermal properties. 2) Quantisation of boundary electric fluxes and gluing procedures for quantum electromagnetism on spacetimes with boundaries.
Cite
@article{arxiv.2509.01458,
title = {Quantum reference frames for spacetime symmetries and large gauge transformations},
author = {Daan W. Janssen},
journal= {arXiv preprint arXiv:2509.01458},
year = {2026}
}
Comments
5pp. Accepted as contribution to the proceedings of The 24th International Conference on General Relativity and Gravitation (GR24) and the 16th Edoardo Amaldi Conference on Gravitational Waves (Amaldi16), based on a talk given in session D4. v2: Corrected a typo in Eq. (2)