Analogue Gravity and Vorticity
Black holes follow general relativity since the dawning of its formulation. Although there have been theoretical developments in the description of these objects in the last century, its experimental observations are still limited. Analogue gravity intends to fill this gap, allowing for a myriad of physical systems that emulate some gravitational aspects in the laboratory. In particular, these analogies enable the experimental realization of sonic black holes which exhibit characteristics of astrophysical black holes. The first modern gravitational analogy was proposed by Unruh in the 80s and is based on the propagation of sound waves in a barotropic, ideal, irrotational fluid. Since the proposal of the hydrodynamic analogy, the field of analogue gravity has experienced a bloom of new models. Under suitable conditions, gravitational analogies exhibit properties of Kerr black holes such as superradiance and quasinormal oscillations. In Bose-Einstein condensates, perturbations are described by quantized fields, which allows for a configuration that emits Hawking radiation. In this work we consider the effect of vorticity on the hydrodynamic analogy. When we do that, the analogy between the hydrodynamic system and gravitation is lost. This hypothesis is justifiable from the fact that real physical systems are not vorticity free. Our objective is to explore if the effects predicted by hydrodynamic analogies, specially superradiance, still hold if there is vorticity.