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

"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.

May 3, 2025 - 22:55

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

"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..."