Superradiance is the term given to radiation enhancement effects, typically associated with black holes, although as well with numerous other phenomena seen in astrophysics and quantum mechanics.
Normally when radiation is incident upon an object it is partially transmitted and partially reflected. However, it has been theorized that in some instances, specifically in a rotating system, that the incident radiation is enhanced as a result of the rotating obstacle. Although being theorized over 50 years ago, and successfully explaining many interesting phenomena, rotational superradiance has never been observed experimentally – that is until now.
A team of physicists at the University of Nottingham conducted experiments in a bath where they were able to simulate a black hole in the form of a draining vortex. The researchers found that the waves propagating on the surface of the water experienced significant amplification after being scattered by the draining vortex. Their results are the first ever experimental measurement of the effects of superradiance, of which they hope is the first of many. This has huge implications for our understanding of black hole dynamics and phenomenology.