Sunday, March 16, 2008

Information May Leak from Black Holes at Dial-Up Speeds

Why a leaky black hole is more like a mirror ball from hell
By JR Minkel



BLACK HOLE MIRROR: Researchers have assumed that if information could emerge from a black hole, it would take eons to do so. However, a new study finds that the turnaround in an older black hole could be more like a few seconds, which would make it more like an information mirror.


NEW ORLEANS—A new study hints that black holes might not be as good at keeping secrets as researchers have long thought. A pair of physicists has reexamined the time it would take for information (think: your iPhone's memory) to potentially escape from inside a black hole.

They find that the 1s and 0s of your address book could be recovered as quickly as 1,000 bits per second—far faster than previously expected. "The black hole really behaves like an information mirror," says physicist John Preskill of the California Institute of Technology in Pasadena.

The finding, presented here at a meeting of the American Physical Society, marks the latest attempt to come to grips with the fate of information that has crossed the black hole event horizon, a boundary beyond which even light cannot escape. There is no doubt, of course, that the ultradense singularity at the heart of a black hole would vaporize an iPhone. The question is whether there is any imaginable way to piece together its original state.

Physicist Stephen Hawking first broached the subject in the 1970s. He postulated that black holes would gradually evaporate by radiating particles (now called Hawking radiation) that had bubbled up from the vacuum around the event horizon. The radiation would be so scrambled, he argued, that when the black hole disappeared after many trillions of years, all the information about its contents would be lost. Other researchers insisted that the data might be imprinted on Hawking's particles, and even Hawking has changed his mind.

As in previous work, Preskill and physicist Patrick Hayden of McGill University in Montreal imagined two citizens of a hyperadvanced civilization, Alice and Bob. Alice wants to destroy some bits (technically, quantum bits that are 0 and 1 simultaneously) by throwing them into a black hole. Bob aims to recover them by gathering all the Hawking radiation from the black hole. Prior research had shown that if Alice dropped her bits into a relatively young black hole, Bob would have to collect the Hawking radiation for half the life of the black hole before being able to decode a single one of Alice's bits.

In the new study, Alice holds onto her bits until after the black hole has reached the halfway mark. Before her data dump, Bob managed to prepare some bits of his own that he entangled with Alice's, meaning they were linked instantaneously across any distance. Preskill reports that Bob could reconstruct Alice's bits by mixing the next few bits of Hawking radiation following the data dump with what he'd already collected, along with his own bits. "It might be a very difficult quantum computation to do the decoding," he says, but Bob would need only about 10 percent more Hawking particles than the number of bits that Alice had thrown in. A black hole the size of the sun would emit up to 1,000 Hawking particles per second, Hayden says.

The catch is that Alice's dumped bits would have to rapidly mix with the rest of the black hole, spreading their entanglement to the outgoing Hawking radiation that Bob collects. Current theories cannot predict the speed at which entanglement would spread across a black hole. Still, researchers are impressed by the novel application of quantum information theory. "I didn't think there was much else you could say about black holes without a quantum theory of gravity," says researcher Fotini Markopoulou of the Perimeter Institute for Theoretical Physics in Waterloo, Ontario.

The effect comes perilously close to contradicting known rules of physics. After reconstructing Alice's bits, Bob could throw his copy into the black hole, where the two copies might run into one another. Such a meeting would violate the uncertainty principle of quantum mechanics because it would allow measurements of both the position and momentum of the identical quantum state. But the few-second delay between when Alice and Bob can dump their respective bits is just long enough, Preskill says, for her bits to be destroyed by the singularity.

Such a narrow escape appeals to Stanford University physicist Leonard Susskind, who explains that if Bob had to wait for half the lifetime of a black hole to extract his first bit, quantum mechanics would be safe by a curiously wide margin, in his view. "I like the idea," he says, "that the most dangerous experiment you can think of is right on the edge."

9 comments:

Anonymous said...

Wonderful blog you have here but I was wondering if you knew of any message
boards that cover the same topics talked about here?
I'd really like to be a part of group where I can get suggestions from other experienced individuals that share the same interest. If you have any suggestions, please let me know. Thanks!

my blog post; can i buy a home with bad credit
my web site :: Can you Get approved for a mortgage with bad Credit

Anonymous said...

Greetings! Quick question that's totally off topic. Do you know how to make your site mobile friendly? My blog looks weird when browsing from my iphone. I'm trying to find a
theme or plugin that might be able to resolve this issue.
If you have any recommendations, please share. With thanks!


Feel free to visit my page :: the loan consolidation

Anonymous said...

Greetings! This is my first visit to your blog! We
are a group of volunteers and starting a new initiative in a community in the
same niche. Your blog provided us beneficial information to
work on. You have done a wonderful job!

Also visit my website - markenkleidung online outlet

Anonymous said...

you are actually a just right webmaster. The web site loading pace
is incredible. It kind of feels that you are doing any unique trick.

Also, The contents are masterwork. you have done a excellent process in this matter!


My web page - start a small business
my web page :: please click the next post

Anonymous said...

It's a pity you don't have a donate button! I'd most certainly donate to this brilliant blog! I suppose for now i'll settle for bookmarking and adding your RSS feed to my Google account.
I look forward to fresh updates and will talk about this
blog with my Facebook group. Talk soon!

Here is my blog ... Call us

Anonymous said...

I like the helpful info you provide in your articles.

I'll bookmark your weblog and check again here regularly. I'm quite sure I will learn many new stuff right
here! Good luck for the next!

Have a look at my page: Www.codecodex.com

Anonymous said...

hey there and thank you for your info – I've definitely picked up anything new from right here. I did however expertise several technical points using this site, as I experienced to reload the web site lots of times previous to I could get it to load properly. I had been wondering if your web hosting is OK? Not that I'm complaining, but slow loading instances times will very frequently affect your placement in google and can damage your quality score if
advertising and marketing with Adwords. Anyway I am adding this RSS to my email and can look out for much
more of your respective fascinating content.
Ensure that you update this again soon.

Have a look at my web site; Going Listed here

Anonymous said...

I saw a weblog on Yahoo and read a number of posts.
good practice! I just added to my Google News Reader.

My web-site :: tally weijl online shop

Anonymous said...

Duperre super-site! I am loving it! ' Will come back once again - take it to eat, thank you.

Also visit my weblog :: Tybee Island Vacation Rentals By Owner