Lab Black Hole Reveals Hawking Radiation Backreaction
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- Lorenzo Procopio of Paderborn University in Germany led a team that observed Hawking radiation backreaction in a black hole analog built from ultrafast laser pulses traveling through a patterned optical fiber, with findings published in Nature.
- Ulf Leonhardt of the Weizmann Institute of Science in Israel, a co-author on the paper, developed the laser-fiber analog setup over a decade ago; one pulse reshapes the fiber to create an event horizon for a second pulse.
- Backreaction — the recoil in which a radiating system surrenders energy equivalent to what its Hawking emission carries away — was detected as a tiny shift in the laser pulse that generated the analog radiation.
- The experiment contradicts previous assumptions that Hawking radiation arises from a complex cascade of optical interactions, instead pointing to a single direct process linked to a biquadratic interaction between the radiation and the analog gravitational field.
- The researchers write that the mechanism, if confirmed in other analog systems, could help resolve the information paradox — a problem Stephen Hawking worked on until his final 2018 paper.
- Hawking radiation itself was first proposed by Stephen Hawking in 1974 as black-body radiation from quantum effects near a black hole's event horizon, but direct detection around a real black hole is expected to remain impossible because the signal is too faint to separate from cosmic background radiation.
Why it matters: The finding reframes Hawking radiation as a simple, direct interaction rather than a complex cascade, giving theorists a tractable microscopic model for how real black holes evaporate — and a potential foothold on the information paradox, a problem Hawking himself never fully resolved before his 2018 paper.
