Regular black holes with improved energy conditions and their analogues in fluids

TL;DR

This paper proposes modifications to regular black hole models to satisfy all but the strong energy condition and explores their analogues in fluid systems for potential experimental simulation.

Contribution

It introduces a method to modify black hole metrics to satisfy energy conditions and develops a framework for simulating these black holes in fluid analogues.

Findings

Modified metrics satisfy weak, null, and dominant energy conditions.

Proved a no-go theorem for conformally related regular black holes.

Provided conditions for experimental simulation in fluid systems.

Abstract

On the premise of the importance of energy conditions for regular black holes, we propose a method to remedy those models that break the dominant energy condition, e.g., the Bardeen and Hayward black holes. We modify the metrics but ensure their regularity at the same time, so that the weak, null, and dominant energy conditions are satisfied, with the exception of the strong energy condition. Likewise, we prove a no-go theorem for conformally related regular black holes, which states that the four energy conditions can never be met in this class of black holes. In order to seek evidences for distinguishing regular black holes from singular black holes, we resort to analogue gravity and regard it as a tool to mimic realistic regular black holes in a fluid. The equations of state for the fluid are solved via an asymptotic analysis associated with a numerical method, which provides a modus operandi for experimental observations, in particular, the conditions under which one can simulate realistic regular black holes in the fluid.