# Quadratic curvature terms and deformed Schwarzschild-de Sitter black hole analogues in the laboratory

## TL;DR

This paper demonstrates how laboratory fluid dynamics experiments can simulate and analyze quasinormal modes of black holes in quadratic curvature gravity, offering a novel way to test gravitational theories.

## Contribution

It introduces a method to study black hole quasinormal modes using acoustic waves in fluid flows, linking laboratory experiments with advanced gravitational theories.

## Key findings

- Laboratory sound wave patterns mimic black hole quasinormal modes.
- Deviations from Schwarzschild solutions are measurable via nozzle cross-sectional area.
- Experimental data constrains parameters of quadratic curvature gravity theories.

## Abstract

Sound waves on a fluid stream, in a de Laval nozzle, are shown to correspond to quasinormal modes emitted by black holes that are physical solutions in a quadratic curvature gravity with cosmological constant. Sound waves patterns in transsonic regimes at a laboratory are employed here to provide experimental data regarding generalized theories of gravity, comprised by the exact de Sitter-like solution and a perturbative solution around the Schwarzschild-de Sitter standard solution. Using the classical tests of General Relativity to bound free parameters in these solutions, acoustic perturbations on fluid flows in nozzles are then regarded to study quasinormal modes of these black holes solutions, providing deviations of the de Laval nozzle cross-sectional area, when compared to the Schwarzschild solution. The fluid sonic point in the nozzle, for sound waves in the fluid, implements the acoustic event horizon corresponding to quasinormal modes.