%0 Journal Article
%A Alonso Serrano, Ana
%A Garay Elizondo, Luis Javier
%A Liška, Marek
%T Black hole thermodynamics probes the equivalence principle
%D 2025
%@ 0218-2718
%U https://hdl.handle.net/20.500.14352/128893
%X The equivalence principle for test gravitational physics strongly constrains dynamics of spacetime, providing a powerful criterion for selecting candidate theories of gravity. However, checking its validity for a particular theory is often a very difficult task. We devise here a simple theoretical criterion for identifying equivalence principle violations in black hole thermodynamics. By employing this criterion, we prove that Lanczos-Lovelock gravity violates the strong equivalence principle, leaving general relativity as the only local, diffeomorphism-invariant theory compatible with it. However, we also show that certain nonlocal expressions for black hole entropy appear to obey the strong equivalence principle.
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