The general Penrose inequality: lessons from numerical evidence

TL;DR

This paper investigates the Penrose inequality in complex black hole configurations using numerical methods, revealing conditions under which the inequality holds or fails, especially in the presence of matter and horizon crossings.

Contribution

It provides the first comprehensive numerical analysis of the Penrose inequality in scenarios with crossing horizons and matter, clarifying when the inequality is valid or violated.

Findings

The Penrose inequality holds for outermost apparent horizons in vacuum cases.

It remains valid for bifurcating horizons regardless of intersection.

The inequality breaks down in matter systems violating the dominant energy condition.

Abstract

Formulation of the Penrose inequality becomes ambiguous when the past and future apparent horizons do cross. We test numerically several natural possibilities of stating the inequality in punctured and boosted single- and double- black holes, in a Dain-Friedrich class of initial data and in conformally flat spheroidal data.The Penrose inequality holds true in vacuum configurations for the outermost element amongst the set of disjoint future and past apparent horizons (as expected)and (unexpectedly) for each of the outermost past and future apparent horizons, whenever these two bifurcate from an outermost minimal surface, regardless of whether they intersect or remain disjoint. In systems with matter the conjecture breaks down only if matter does not obey the dominant energy condition.