An international team of physicists has observed a key process associated with Hawking radiation in a laboratory experiment, a finding that could improve understanding of how black holes lose energy and shed light on the long-standing black hole information paradox.
The study, led by Lorenzo Procopio of Paderborn University in Germany, was published in the journal Nature.
In 1974, physicist Stephen Hawking proposed that black holes are not entirely black but slowly emit thermal radiation, now known as Hawking radiation, due to quantum effects near the event horizon. Over extremely long periods, this process could cause black holes to gradually evaporate.
A major unanswered question has been how black holes lose energy when emitting this radiation, a process known as backreaction.
Because Hawking radiation from actual black holes is too weak to detect with current technology, the researchers recreated black hole-like conditions in a laboratory using ultrafast laser pulses travelling through a specially designed optical fibre. One laser pulse altered the fibre's optical properties, creating an analogue of a black hole event horizon for a second pulse.
The team detected evidence of backreaction by measuring a small energy-related shift in the laser pulse that generated the analogue black hole.
The experiment also produced an unexpected result. Previous theories suggested that Hawking radiation in laboratory systems arose through a complex sequence of interactions. The researchers found that both the radiation and the associated energy loss appeared to originate through a single, direct process.
The scientists said the finding raises the possibility that Hawking radiation from real black holes may also be generated through a simpler mechanism than previously thought.
They added that further experiments will be needed to determine whether the result applies more broadly, but described the study as an important step towards understanding black hole evaporation and the black hole information paradox.