In one minute

Procopio, Aguero-Santacruz, Bermudez and Leonhardt address an open question: Hawking radiation draws its energy from the field around a black hole, but how field quanta create Hawking quanta was unknown. In a fibre-optical analogue of an event horizon, they present experimental and theoretical evidence for the generating process. Where a complicated cascade had been assumed, they identify a simple direct process and observe how it reacts back on the field. Such analogues rest on waves in a medium whose flow comes to exceed the wave speed. The findings point to an equally direct process in other analogues and perhaps in gravity, shedding light on how black holes might radiate.

Backreaction of stimulated Hawking radiation in an optical analogue