  The zeroth law of black hole mechanics is an assertion of constancy of the
surface gravity on a stationary Killing horizon. The Hawking temperature of the
black hole horizon is proportional to the surface gravity. Therefore, the
constancy of the surface gravity is reminiscent of the zeroth law of ordinary
thermodynamics. In this work, we provide a proof of the zeroth law in
Lanczos-Lovelock theories of gravity, where the Einstein Hilbert action is
supplemented by higher curvature terms.

General Relativity and Quantum Cosmology;High Energy Physics - Theory