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Title: Scientists Simulate First-Ever 'Black Hole Bomb' Laboratory Analog

Link: https://science.slashdot.org/story/25/05/03/2...

"Researchers have created the first laboratory analog of the 'black hole
bomb'," reports ScienceAlert, "a theoretical concept developed by physicists
in the 1970s..." There's no black hole involved; their experiment just
simulates the "electromagnetic analogue" of the theoretical concept - the
"exponential runaway amplification of spontaneously generated electromagnetic
modes." Or, as ScienceAlert puts it, "It doesn't, just to set your mind at
ease, pose any danger. It consists of a rotating aluminum cylinder, placed
inside layers of coils that generate magnetic fields that rotate around it,
at controllable speeds." As Roger Penrose proposed in 1971, the powerful
rotational energy of a spinning black hole could be used to amplify the
energy of nearby particles. Then, physicist Yakov Zel'Dovich figured out that
you didn't need a black hole to see this phenomenon in action. An axially
symmetrical body rotating in a resonance chamber, he figured, could produce
the same energy transfer and amplification, albeit on a much smaller scale.
Later work by other physicists found that, if you enclose the entire
apparatus in a mirror, a positive feedback loop is generated, amplifying the
energy until it explodes from the system. This concept was named the black
hole bomb, and a team of physicists led by Marion Cromb of the University of
Southampton in the UK now claim to have brought it to life. A paper
describing their experiment has been uploaded to preprint server arXiv...
[W]hat the team's experiment does is simulate it, using magnetic fields as a
proxy for the particles, with the coils around the system acting as the
reflector to produce the feedback loop. When they ran the experiment, they
found that, when the cylinder is rotating faster than, and in the same
direction as, the magnetic field, the magnetic field is amplified, compared
to when there is no cylinder. When the cylinder rotates more slowly than the
magnetic field, however, the magnetic field is dampened. This is a really
interesting result, because it demonstrates a very clear amplification
effect, based on the theories described decades ago... Because we can't probe
black holes directly, analogs such as this are an excellent way to understand
their properties... [T]he experiment could represent a significant step
towards better understanding the physics of the most gravitationally extreme
objects in the Universe. "The exponential amplification from noise supports
theoretical investigations into black hole instabilities," the researchers
write, "and is promising for the development of future experiments to observe
quantum friction in the form of the Zeldovich effect seeded by the quantum
vacuum..."

Read more of this story at Slashdot.

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