Physicists create sonic black hole in the lab
January 10, 2011
(PhysOrg.com) -- Black holes get their name because they absorb all incoming light, and are so dense that none of that light can escape their event horizon. In a new study, scientists have created a sonic analogue of a black hole in the lab – that is, a sonic black hole in which sound waves rather than light waves are absorbed and cannot escape. The scientists hope that the short-lived sonic black hole could allow them to observe and study the elusive Hawking radiation that is predicted to be emitted by traditional black holes, which has so far been a very difficult task.
The scientists, Oren Lahav and coauthors from the Technion-Israel Institute of Technology in Haifa, Israel, have published their study on the sonic black hole in a recent issue of Physical Review Letters.
The researchers created the sonic black hole in a Bose-Einstein condensate made of 100,000 rubidium atoms slowed to their lowest quantum state in a magnetic trap. This cold cluster of atoms acts like a single, large quantum mechanical object. In order to transform this condensate into a sonic black hole, the scientists had to find a way to accelerate some of the condensate to supersonic speeds so that the condensate would contain some regions of supersonic flow and some regions of subsonic flow.
The scientists achieved this acceleration by shining a large-diameter laser on the condensate in such a way as to create a steplike potential and a harmonic potential. When the condensate crosses the “step” in the steplike potential, the condensate accelerates to supersonic speeds. The scientists demonstrated that the condensate could accelerate to more than an order of magnitude faster than the speed of sound.
“The greatest significance of our article is that we succeeded in overcoming the Landau critical velocity, which states that flow cannot exceed the speed of sound,” coauthor Jeff Steinhauer of the Technion-Israel Institute of Technology told PhysOrg.com. “Our experiment exceeds this limit for a finite period of time.”
January 10, 2011
(PhysOrg.com) -- Black holes get their name because they absorb all incoming light, and are so dense that none of that light can escape their event horizon. In a new study, scientists have created a sonic analogue of a black hole in the lab – that is, a sonic black hole in which sound waves rather than light waves are absorbed and cannot escape. The scientists hope that the short-lived sonic black hole could allow them to observe and study the elusive Hawking radiation that is predicted to be emitted by traditional black holes, which has so far been a very difficult task.
The scientists, Oren Lahav and coauthors from the Technion-Israel Institute of Technology in Haifa, Israel, have published their study on the sonic black hole in a recent issue of Physical Review Letters.
The researchers created the sonic black hole in a Bose-Einstein condensate made of 100,000 rubidium atoms slowed to their lowest quantum state in a magnetic trap. This cold cluster of atoms acts like a single, large quantum mechanical object. In order to transform this condensate into a sonic black hole, the scientists had to find a way to accelerate some of the condensate to supersonic speeds so that the condensate would contain some regions of supersonic flow and some regions of subsonic flow.
The scientists achieved this acceleration by shining a large-diameter laser on the condensate in such a way as to create a steplike potential and a harmonic potential. When the condensate crosses the “step” in the steplike potential, the condensate accelerates to supersonic speeds. The scientists demonstrated that the condensate could accelerate to more than an order of magnitude faster than the speed of sound.
“The greatest significance of our article is that we succeeded in overcoming the Landau critical velocity, which states that flow cannot exceed the speed of sound,” coauthor Jeff Steinhauer of the Technion-Israel Institute of Technology told PhysOrg.com. “Our experiment exceeds this limit for a finite period of time.”
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