Mechanism by which information can be recovered from black holes identified

Washington, May 15 : Physicists at Penn State in the US have provided a mechanism by which information can be recovered from black holes.

Black holes are those regions of space where gravity is so strong that, according to Einstein's theory of general relativity, not even light can escape.

The team's findings pave the way toward ending a decades-long debate sparked by renowned physicist Steven Hawking.

In the 1970s, Hawking showed that although black holes evaporate by quantum processes, information, such as the identity of matter that is gobbled up by black holes, is permanently lost.

At the time, Hawking's assertion threatened to turn quantum mechanics - the most successful physical theory posited by humankind - on its head, since a fundamental tenet of the theory is that information cannot be lost.

Though Hawking himself renounced the idea in 2004, yet no one, until now, has been able to provide a plausible mechanism for how information might escape from a black hole.

A team of physicists led by Abhay Ashtekar, Holder of the Eberly Family Chair in Physics and director of the Penn State Institute for Gravitation and the Cosmos, now has discovered such a mechanism.

To conduct their studies, the team used a two-dimensional model of black holes to investigate the quantum nature of real black holes, which exist in four dimensions.

Broadly, their findings expand space-time beyond its assumed size, thus providing room for information to reappear.

According to Ashtekar, "Hawking's analysis suggested that at the end of a black hole's life, even after it has completely evaporated away, a singularity, or a final edge to space-time, is left behind, and this singularity serves as a sink for unrecoverable information."

But Ashtekar and his collaborators, Victor Taveras, and Madhavan Varadarajan, a professor at the Raman Research Institute in India, suggest that singularities do not exist in the real world.

"Information only appears to be lost because we have been looking at a restricted part of the true quantum-mechanical space-time," said Ashtekar.

"Once you consider quantum gravity, then space-time becomes much larger and there is room for information to reappear in the distant future on the other side of what was first thought to be the end of space-time," he added.

ANI