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  • Letter
  • Open Access

Tantum gravity

Florian Ecker*, Adrien Fiorucci†, and Daniel Grumiller‡

  • Institute for Theoretical Physics, TU Wien, Wiedner Hauptstrasse 8–10/136, A-1040 Vienna, Austria

  • *Contact author: fecker@hep.itp.tuwien.ac.at
  • †Contact author: adrien.fiorucci@tuwien.ac.at
  • ‡Contact author: grumil@hep.itp.tuwien.ac.at
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Phys. Rev. D 111, L021901 – Published 22 January, 2025

DOI: https://doi.org/10.1103/PhysRevD.111.L021901

Abstract

We argue there is an interesting triple-scaling limit of quantum gravity, namely when Planck’s constant scales to infinity while Newton’s constant and the speed of light tend to zero, keeping fixed the gravitational coupling GNc−4 and the combination ℏc. We refer to this limiting theory as “tantum gravity” and describe in this Letter some of its main properties and prospects for physics. Most notably, the laws of black hole thermodynamics survive this limit, which means that puzzles related to black holes and their evaporation could be addressed more easily in tantum gravity than in fully fledged quantum gravity.

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Phys. Rev. D 111, L021901– Published 22 January, 2025
  • Received 24 May 2024
  • Accepted 5 January 2025
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