An artist's concept of a black hole with layers of material collecting around it.
Credit: NASA
SYDNEY: A trick of the light has allowed U.S. scientists to mimic the physics of black holes in the laboratory.
Reported in the journal Physical Review Letters, the study paves the way for the first test of a number of theories surrounding the concept of black holes, including the existence of Hawking radiation.
"There are several unanswered questions regarding black holes and Hawking radiation, which rely on untested assumptions about black hole physics," said lead researcher Paul Nation, a physicist at Dartmouth College in Hanover, New Hampshire.
"We showed that by using a superconducting circuit, we could mimic the effects of a black hole as seen by the light inside our device, and answer all these questions."
All consuming void
British cosmologist Stephen Hawking first proposed this exotic variety of radiation 35 years ago. He predicted that black holes were not merely all-consuming voids, but also emitted radiation in the form of photons released from the 'event horizon' - the point of no return for an observer falling into a black hole.
To date, however, Hawking radiation has not been proven to exist. This is because we have no measurements from real black holes and recreating a black hole on Earth would be tricky and inadvisable.
"[Hawking's] calculations relied on assumptions about the physics of ultra-high energies and quantum gravity. Because we can't yet take measurements from real black holes, we need a way to recreate this phenomenon in the lab in order to study it, to validate it," said Nation.
Semiconducting SQUID
His team struck upon the idea of making a model to test Hawking radiation - not a real black hole, but a system that behaves as though it contains a black hole.
They used an array of semiconductors - known as SQUIDs (or superconducting quantum interference devices) - to generate a pulsed magnetic field. This pulsing field can be used to control the speed of light.
In a real black hole, the event horizon occurs when an observer's velocity matches the speed of light. In the model device, an artificial horizon can be created by matching the speed of the pulsing field to the manipulated speed of light.
