Published March 25, 2025 | Version Published
Journal Article Open

Quantum Mechanics of a Spherically Symmetric Causal Diamond in Minkowski Spacetime

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon University of Amsterdam

Abstract

We construct the phase space of a spherically symmetric causal diamond in (d+2)-dimensional Minkowski spacetime. Utilizing the covariant phase space formalism, we identify the relevant degrees of freedom that localize to the d-dimensional bifurcate horizon and, upon canonical quantization, determine their commutators. On this phase space, we find two Iyer-Wald charges. The first of these charges, proportional to the area of the causal diamond, is responsible for shifting the null time along the horizon and has been well documented in the literature. The second charge is much less understood, being integrable for d≥2 only if we allow for field-dependent diffeomorphisms and is responsible for changing the size of the causal diamond.

Copyright and License

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

Acknowledgement

We would like to thank Luca Ciambelli, Laura Donnay, Laurent Freidel, Antony Speranza, and Céline Zwikel for useful discussions. M. B., T. H., Y. Z., and K. Z. are supported by the Heising-Simons Foundation “Observational Signatures of Quantum Gravity” collaboration Grant No. 2021-2817, the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under Award No. DE-SC0011632, and the Walter Burke Institute for Theoretical Physics. M. B., Y. Z., and K. Z. are also supported by GQuEST funding provided from the U.S. Department of Energy via FNAL: DE-AC02-07CH11359. M. B. acknowledges the support of the Natural Sciences and Engineering Research Council of Canada (NSERC) [Funding Reference No. PGS D—578032–2023]. P. M. is supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 852386). The work of K. Z. is also supported by a Simons Investigator Award.

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Additional details

Related works

Is new version of
Discussion Paper: arXiv:2408.11094 (arXiv)

Funding

Heising-Simons Foundation
2021-2817
United States Department of Energy
DE-SC0011632
Walter Burke Institute for Theoretical Physics
United States Department of Energy
DE-AC02-07CH11359
Natural Sciences and Engineering Research Council
PGS D—578032–2023
European Research Council
European Commission
852386
Simons Foundation
SCOAP3

Dates

Accepted
2025-03-12

Caltech Custom Metadata

Caltech groups
Walter Burke Institute for Theoretical Physics, Division of Physics, Mathematics and Astronomy (PMA)
Publication Status
Published