In a first, Hawking radiation mimicked in lab settings
Scientists have created a lab-scale imitation of a black hole that emits Hawking radiation - the particles predicted to escape black holes due to quantum mechanical effects.
London: Scientists have created a lab-scale imitation of a black hole that emits Hawking radiation - the particles predicted to escape black holes due to quantum mechanical effects.
Such objects could one day help resolve the so-called 'black hole information paradox' - the question of whether information that falls into a black hole disappears forever, a report in the journal Nature Physics said.
The black hole analogue was created by trapping sound waves using an ultra-cold fluid.
The physicist Stephen Hawking stunned cosmologists 40 years ago when he announced that black holes are not totally black, calculating that a tiny amount of radiation would be able to escape the pull of a black hole.
This raised the tantalising question of whether information might escape too, encoded within the radiation.
Hawking radiation relies on a basic tenet of quantum theory - large fluctuations in energy can occur for brief moments of time.
Jeff Steinhauer, physicist at the Technion-Israel Institute of Technology in Haifa, used a collection of rubidium atoms chilled to less than 1-billionth of a degree above absolute zero.
Using laser light, Steinhauer manipulated the fluid to flow faster than the speed of sound.
"Like a swimmer battling a strong current, sound waves travelling against the direction of the fluid become 'trapped'. The condensate, thus, becomes a stand-in for the gravitational event horizon," explained Steinhauer.
Steinhauer is now working to develop the technology without having to amplify the sonic radiation.
This could allow him to use his "Hawking radiation" to explore the information paradox.
Some researchers say it is still not clear how closely this laboratory model, which took Steinhauer five years to perfect, mimics Hawking radiation.
But even if the sonic radiation as it stands is not a perfect match, William Unruh, theoretical physicist at the University of British Columbia in Vancouver points out that "it is the closest anyone has come" to detecting Hawking radiation.