The return of the membrane paradigm? Black holes and strings in the water tap

TL;DR

This paper explores the membrane paradigm to understand higher-dimensional black holes and strings, showing a fluid analogy that explains gravitational instabilities and phase transitions.

Contribution

It establishes a classical fluid analogy for black string instabilities and phase transitions, providing new insights into higher-dimensional gravity.

Findings

Black string instabilities mirror fluid Rayleigh-Plateau instability

Features like threshold modes and phase transitions are explained by the fluid analogy

Rotating black holes' stability and bifurcations can be understood through this model

Abstract

Several general arguments indicate that the event horizon behaves as a stretched membrane. We propose using this relation to understand gravity and dynamics of black objects in higher dimensions. We provide evidence that (i) the gravitational Gregory-Laflamme instability has a classical counterpart in the Rayleigh-Plateau instability of fluids. Each known feature of the gravitational instability can be accounted for in the fluid model. These features include threshold mode, dispersion relation, time evolution and critical dimension of certain phase transitions. Thus, we argue that black strings break in much the same way as water from a faucet breaks up into small droplets. (ii) General rotating black holes can also be understood with this analogy. In particular, instability and bifurcation diagrams for black objects can easily be inferred. This correspondence can and should be used as a guiding tool to understand and explore physics of gravity in higher dimensions.