Luca Giacomelli
INO-CNR BEC Center Trento - luca.giacomelli-1@unitn.itAnalogue gravity is an approach that uses condensed matter systems to mimic some aspects of the physics of gravitational systems; for example sound in a moving fluid can be described like a relativistic field in a curved spacetime. An interesting mechanism to study is superradiance, that is the amplified scattering of radiation from a rotating black hole; this phenomenon was recently observed in a draining vortex in water. To better understand superradiance, we introduce a geometrically simpler (but realizable) toy model based on an atomic BEC subject to a synthetic gauge field. Besides giving a simple picture of classical superradiant phenomena, the use of a low-temperature system also allows to investigate quantum aspects. We also show how, from this picture, the instabilities associated to superradiance can be seen to come into play in some relevant BEC configurations, such as multiply quantized vortices.
Related paper: https://arxiv.org/abs/2011.01736, https://arxiv.org/abs/2006.09259, https://arxiv.org/abs/2105.03964