Quantum curvature fluctuations and the cosmological constant in a single plaquette quantum gravity model

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Authors

BLITZ Samuel Harris MAJID Shahn

Year of publication 2025
Type Article in Periodical
Magazine / Source Classical and Quantum Gravity
MU Faculty or unit

Faculty of Science

Citation BLITZ, Samuel Harris and Shahn MAJID. Quantum curvature fluctuations and the cosmological constant in a single plaquette quantum gravity model. Classical and Quantum Gravity. IOP Publishing Ltd, 2025, vol. 42, No 4, p. 1-11. ISSN 0264-9381. Available from: https://dx.doi.org/10.1088/1361-6382/ada90c.
web https://iopscience.iop.org/article/10.1088/1361-6382/ada90c
Doi http://dx.doi.org/10.1088/1361-6382/ada90c
Keywords quantum gravity; noncommutative riemannian geometry; cosmological constant
Description Understanding the microscopic behavior of spacetime, in particular quantum uncertainty in the Ricci scalar, is critical for developing a theory of quantum gravity and perhaps solving the cosmological constant problem. To test this, we compute this quantity for a simple but exact discrete quantum gravity model based on a single plaquette of spacetime. Our results confirm initial speculations of Wheeler from 1955 in finding a UV divergence in the quantum uncertainty. We further show that this behavior is stable under renormalization, but potentially unstable with the introduction of a cosmological constant, suggesting that a bare cosmological constant is ruled out.
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