On a geometric interpretation of the 1/4 factor in black hole entropy
Abstract
The Bekenstein--Hawking entropy $S = A/4\ell_p^2$ contains a coefficient$1/4$ that has been calculated by many approaches to quantum gravity.We show that for any null causal boundary in afour-dimensional Lorentzian spacetime, including horizons, that factor would naturally arise from geometry.A heuristic accessibility argument based on null causal structureis supported by a geometry-only derivation using the canonicalsymplectic structure on $T^*M$ and the double-cone structure ofnull covectors.No gravitational field equations or thermodynamic assumptionsare invoked.
Fields of Study & Subjects
Black Holes and Theoretical Physics
Relativity and Gravitational Theory
Noncommutative and Quantum Gravity Theories
Publication details
- Journal / source
- Zenodo (CERN European Organization for Nuclear Research)
- Publication date
- 15 February 2026
- Language
- EN
- Document type
- Preprint