Quantum coordinates, localisation of events, and the quantum hole argument

Autor(en)

Viktoria Kabel, Anne Catherine de la Hamette, Luca Apadula, Carlo Cepollaro, Henrique Gomes, Jeremy Butterfield, Časlav Brukner

Abstrakt

The study of quantum reference frames (QRFs) is motivated by the idea of taking into account the quantum properties of the reference frames used, explicitly or implicitly, in our description of physical systems. Like classical reference frames, QRFs can be used to define physical quantities relationally. Unlike their classical analogue, they relativise the notions of superposition and entanglement. Here, we explain this feature by examining how configurations or locations are identified across different branches in superposition. We show that, in the presence of symmetries, whether a system is in “the same” or “different” configurations across the branches depends on the choice of QRF. Hence, sameness and difference — and thus superposition and entanglement — lose their absolute meaning. We apply these ideas to the context of semi-classical spacetimes in superposition and use coincidences of four scalar fields to construct a comparison map between spacetime points in the different branches. This reveals that the localisation of an event is frame-dependent. We discuss the implications for indefinite causal order and the locality of interaction and conclude with a generalisation of Einstein’s hole argument to the quantum context.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

Österreichische Akademie der Wissenschaften (ÖAW), University of Oxford, University of Cambridge

Journal

Communications Physics

Band

8

Anzahl der Seiten

18

ISSN

2399-3650

DOI

https://doi.org/10.48550/arXiv.2402.10267

Publikationsdatum

04-2025

Peer-reviewed

Ja

ÖFOS 2012

103025 Quantenmechanik, 103028 Relativitätstheorie

ASJC Scopus Sachgebiete

Allgemeine Physik und Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/9ab9dbcb-b5f3-4099-984a-52eff80e0c55