Researchers set new distance record (144km) in quantum communication/teleportation of qubits!
Posted: 04 June 2007 10:47 PM   [ Ignore ]
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To quote Richard Feynman, “If you think you understand quantum mechanics, you don’t understand quantum mechanics.” This stuff is fascinating:

New distance record for quantum communication

A quantum communication has been sent across a record 144 kilometres (90 miles) using a process which may one day be used to send secret messages across space via a network of satellites. Quantum teleportation involves “entangling” two particles so that any change to the state of one also occurs instantly in its twin, wherever it may be.

The researchers entangle a pair of photons and then fire a single photon at one of the pair. The resulting interaction changes the state of both entangled photons, effectively teleporting a quantum bit of information - known as a qubit - from one place to another. The entangled photons behave “like psychic twins”, the researchers say: even if they are far apart, a disturbance to one affects the other - an oddity that Albert Einstein dubbed “spooky interaction.”

Marked improvement

In the experiment, polarisation-entangled photon pairs were generated on Roque de los Muchachos, a mountain observatory on the island of La Palma in Spain’s Canary Islands. While one photon stayed in La Palma, its twin was sent over an optical free-space link to Tenerife about 144 kilometres away, where the Optical Ground Station of the European Space Agency acted as a receiver. It was a marked improvement over the 13-km distance achieved earlier in a similar. The international team of researchers were able to generate a quantum cryptographic key over 144 km. They described their experiment as “an essential first step towards future satellite-based quantum communication and experiments on quantum physics in space”.

Journal reference: Nature Physics (DOI: 10.1038/nphys629)

ORIGINAL ARTICLE: http://www.newscientist.com/article.ns?id=dn11985&feedId=online-news_rss20

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Posted: 05 June 2007 02:29 AM   [ Ignore ]   [ # 1 ]
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The entire quantum mechanics concepts are so bizarre that in forty years they will have completely destroyed my entire scientific belief system.  Thank goodness that I’ll only live a maximum of twenty more years.  LOL

Occam

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Posted: 05 June 2007 08:14 AM   [ Ignore ]   [ # 2 ]
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Occam - 05 June 2007 02:29 AM

The entire quantum mechanics concepts are so bizarre that in forty years they will have completely destroyed my entire scientific belief system.  Thank goodness that I’ll only live a maximum of twenty more years.  LOL

Occam

That’s funny…

But at least you’d be willing to change that belief system, rather than hold on to it and mold it to suit your needs. Thus the greatness of reason.

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Posted: 05 June 2007 08:19 AM   [ Ignore ]   [ # 3 ]
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It bears repeating that quantum communication does not allow information to be sent faster than light. (Even though the “entaglement” effects are instantaneous, they are such as to not allow information to pass by this method). However I have heard that it does allow for uncrackable crypto. Will be interesting to see how this develops.

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Doug

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Posted: 05 June 2007 11:46 AM   [ Ignore ]   [ # 4 ]
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At the risk of deviating the focus of this thread, I was listening to Paul Davies on a podcast of Science Friday from NPR this morning, talking about his book about why life and consciousness are integral to the shaping and development of the fundamental laws of physics. He uses this action at a distance phenomenon as a mechanism to explain what seems to me his a priori assumption that the universe is congenial to life because life exists and shapes the laws of the universe to facilitate its own existence. Sounds like mystical mumbo-jumbo to me, sort of atheist mysticism a la Entity’s previous threads on the purpose of the universe. Has anyone read the book? Am I too stuck in my old-fashioned, Newtonian mindset, or is it really more reasonable to see the evolution of life as just another expression of the laws of the universe with no special purpose or importance?

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Posted: 05 June 2007 12:07 PM   [ Ignore ]   [ # 5 ]
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Well, Brennen, I think one place to start with that sort of question is to read through some of Victor Stenger’s stuff. He’s an actual physicist ...

Check THIS out, for instance, or THIS, or THIS ... but probably particularly HERE.

[ Edited: 05 June 2007 12:09 PM by dougsmith ]
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Posted: 05 June 2007 03:12 PM   [ Ignore ]   [ # 6 ]
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And, I think we have to recognize that The “old-fashioned Newtonian mindset” serves us very well in our environment since we are not obviously affected by either the micro-universe of quantum mechanics (I don’t worry about Heisenberg or Schroedinger when I want to make a decision), or the macro-universe of relativity (when I drop something, I don’t think that it’s sliding around a bent three dimensional space because of the warping caused by the mass of the earth as I reach down to catch it).

I suppose these quantum and relativity concepts will be second nature to kids a few generations from now, but I don’t believe trying to apply them to my every-day life now would accomplish much.

Occam

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Posted: 05 June 2007 05:24 PM   [ Ignore ]   [ # 7 ]
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Doug,

Thanks! Yeah, it sounded like BS to me, but there wasn’t enough detail in the discussion to say for sure. He seemed dead set against the idea that conditions are suitable for life because it just happened to work out that way, and that our presence as observers is fortuitous for us, but meaningless to the universe as a whole. He even went so far as to say he was undecided on the philosophical question of whether anything not observed by a consciousness could be said to exist at all. I wonder where all the trees and rocks and little furry animals go when no one is watching them.

He presented no evidence for these assumptions except to say that he thought that any theory involving chance as the main reason we get to be here seems unlikley to him. He also kept referring to spooky action at a distance as a mechanism by which our presence as observers could be retroactively fine-tuning the universe to make us possible. Horsesh*t if you ask me. Thanks again for the links.

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