Archive for April 2016

Is the black hole at our galaxy’s centre a quantum computer?

After you die, your body’s atoms will disperse and find new venues, making their way into oceans, trees and other bodies. But according to the laws of quantum mechanics, all of the information about your body’s build and function will prevail. The relations between the atoms, the uncountable particulars that made you you, will remain forever preserved, albeit in unrecognisably scrambled form – lost in practice, but immortal in principle.

There is only one apparent exception to this reassuring concept: according to our current physical understanding, information cannot survive an encounter with a black hole. Forty years ago, Stephen Hawking demonstrated that black holes destroy information for good. Whatever falls into a black hole disappears from the rest of the Universe. It eventually reemerges in a wind of particles – ‘Hawking radiation’ – that leaks away from the event horizon, the black hole’s outer physical boundary. In this way, black holes slowly evaporate, but the process erases all knowledge about the black hole’s formation. The radiation merely carries data for the total mass, charge and angular momentum of the matter that collapsed; every other detail about anything that fell into the black hole is irretrievably lost.

Hawking’s discovery of black-hole evaporation has presented theoretical physicists with a huge conundrum: general relativity says that black holes must destroy information; quantum mechanics says it cannot happen because information must live on eternally. Both general relativity and quantum mechanics are extremely well-tested theories, and yet they refuse to combine. The clash reveals something much more fundamental than a seemingly exotic quirk about black holes: the information paradox makes it aptly clear that physicists still do not understand the fundamental laws of nature.

But Gia Dvali, professor of physics at the Ludwig-Maximilians University of Munich, believes he’s found the solution. ‘Black holes are quantum computers,’ he says. ‘We have an explicit information-processing sequence.’ If he is correct, the paradox is no more, and information truly is immortal. Even more startling, perhaps, is that his concept has practical implications. In the future, we might be able to tap black-hole physics to construct quantum computers of our own.

Read full article: Is the black hole at our galaxy’s centre a quantum computer? | Aeon Essays

Discovery Could Rewrite History of Vikings in New World

POINT ROSEE, Canada It’s a two-mile trudge through forested, swampy ground to reach Point Rosee, a narrow, windswept peninsula stretching from southern Newfoundland into the Gulf of St. Lawrence.

Last June, a team of archaeologists was drawn to this remote part of Canada by a modern-day treasure map: satellite imagery revealing ground features that could be evidence of past human activity.

The treasure they discovered here—a stone hearth used for working iron—could rewrite the early history of North America and aid the search for lost Viking settlements described in Norse sagas centuries ago.

To date, the only confirmed Viking site in the New World is L’Anse aux Meadows, a thousand-year-old way station discovered in 1960 on the northern tip of Newfoundland. It was a temporary settlement, abandoned after just a few years, and archaeologists have spent the past half-century searching for elusive signs of other Norse expeditions.

The confirmed discovery of a Norse camp at L’Anse aux Meadows proved that the Viking sagas weren’t entirely fiction. A second settlement at Point Rosee would suggest that the Norse exploration of the region wasn’t a limited undertaking, and that archaeologists should expand their search for evidence of other settlements, built 500 years before the arrival of Christopher Columbus.

“For a long time, serious North Atlantic archaeologists have largely ignored the idea of looking for Norse sites in coastal Canada because there was no real method for doing so,” says Bolender. “If Sarah Parcak can find one Norse site using satellites, then there’s a reasonable chance that you can use the same method to find more, if they exist. If Point Rosee is Norse, it may open up coastal Canada to a whole new era of research.”

Read whole article: Discovery Could Rewrite History of Vikings in New World