Generic weak isolated horizons

TL;DR

This paper relaxes the boundary conditions of weak isolated horizons to their weakest form, ensuring the laws of black hole mechanics still hold and unifying extremal and non-extremal black holes for broader applications.

Contribution

It introduces a more general formulation of weak isolated horizons that preserves key laws and treats extremal and non-extremal black holes uniformly.

Findings

Zeroth and first laws of black hole mechanics are preserved under relaxed conditions.

The formulation applies to both analytic and numerical relativity.

Extremal and non-extremal black holes are treated on equal footing.

Abstract

Weak isolated horizon boundary conditions have been relaxed supposedly to their weakest form such that both zeroth and the first law of black hole mechanics still emerge, thus making the formulation more amenable for applications in both analytic and numerical Relativity. As an additional gain it explicitly brings the non-extremal and extremal black holes at the same footing.