Analogue simulations of quantum gravity with fluids

Abstract

Technological advances in controlling and manipulating fluids have enabled the experimental realization of acoustic analogues of gravitational black holes. A flowing fluid provides an effective curved spacetime on which sound waves can propagate, allowing the simulation of gravitational geometries and related phenomena. The past decade has witnessed various hydrodynamic experiments testing disparate aspects of black-hole physics culminating with experimental evidence of Hawking radiation and Penrose superradiance. In this Perspective article, we discuss the potential use of analogue hydrodynamic systems beyond classical general relativity towards the exploration of quantum gravitational effects. These include possible insights into the information-loss paradox, black-hole physics with Planck-scale quantum corrections, emergent gravity scenarios and the regularization of curvature singularities. We aim at bridging the gap between the non-overlapping communities of experimentalists working with classical and quantum fluids and quantum-gravity theorists, by illustrating the opportunities made possible by the latest experimental and theoretical developments in these areas. Experiments in fluids have enabled the simulation of several aspects of black holes and quantum field theory in curved spacetime. This Perspective article discusses possible hydrodynamic simulators of quantum gravitational effects, ranging from the resolution of curvature singularities to the emergence of spacetime geometry from quantum degrees of freedom.