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Quantum Teleportation Achieved Over 16 km In China
Laxori666 writes "Scientists in China have succeeded in teleporting information between photons farther than ever before. They transported quantum information over a free space distance of 16 km (10 miles), much farther than the few hundred meters previously achieved, which brings us closer to transmitting information over long distances without the need for a traditional signal."
Unfortunately, what they transmitted was an email for Vi4gra, using an open wifi connection at a Starbucks 10 miles down the road.
Tequila: It's not just for breakfast anymore!
Before you think this is awesome, this is not an ansible, information is transmitted at lightspeed only.
And once they get to an economic level that is closer to what the rest of us enjoy in the Western world, they will start caring. When you are hungry, you only want bread. When you are homeless, you only want shelter. When you have plenty to eat and a decent place to live, you want freedom.
Tequila: It's not just for breakfast anymore!
Isn't it impossible to transmit information via quantum entanglement? Since you cannot determine the state of an entangled particle, you cannot use it to "transmit" information until after you let the other end know, through conventional channels, what each possible state actually stands for. If that's the case, how exactly is this "quantum information transfer" supposed to work.
"In prison you just have to shut your eyes and take it. Here you have to shut your eyes and give it."
Dare I say, if you don't find xkcd funny, the material might be somewhat... not aimed at you.
To be delicate.
Especially if you don't find *any* of them funny (although not all of them are designed to be humourous).
http://science.slashdot.org/story/10/04/19/0132246/Chinas-Research-Ambitions-Hurt-By-Faked-Results
This story alone makes me skeptical about any major scientific breakthroughs until someone can peer review the results.
Congrats to the hardworking people on the project, however I will be applauding their work with less skepticism when I hear that MIT, Cornell, CMU, etc confirm the results.
When you have plenty to eat and a decent place to live, you want freedom.
Or maybe you are just too scared of losing that prosperity that you decide not to rock the boat.
When information is power, privacy is freedom.
I never got any of this newfangled philotic physics. Half of it nobody understands anyway.
No, everyone understands and doesn't understand quantum philotics at the same time, until they are tested. It averages out to half of the population, though.
I believe Quantum entanglement is actually a minimum of 10'000 times the speed of light. http://en.wikipedia.org/wiki/Quantum_entanglement#Experiment_measures_.22speed.22_of_the_quantum_non-local_connection
Information has no mass, so why can't it?
Don't feel bad, this is a pretty common mistake. People read about non-locality and how what happens to one half of an entangled pair affects the other half instantly no matter how far away it is. There does remain some philosophical debate over what entanglement and non-locality really are, but one thing has been supported very well by both theory and experiment: You can't transmit information or power faster than c. In the case of entangled pairs, actions on one half can have a non-local effect that propagates faster than c, but it's not possible to transmit information or power using that effect. In order to make sense of the results and actually observe the effects of non-locality, you typically need to send additional information classically.
So, this will not lead to lag-less communication over vast distances. What it will lead to is quantum crypto networks. Long distance entanglement swapping or quantum teleportation are one of the key ingredients to building a scalable network.
Actually... http://en.wikipedia.org/wiki/Photons#Experimental_checks_on_photon_mass they're still not sure :P
Buanzo Consulting - 15 Years of GNU/Linux experience, for you.
Odd, because I tend to feel as if I understand it and don't understand it at the same time.
It's only when somebody asks me if I understand it that I come to a conclusion, either way.
Me too, but then I get tangled up and with mixed emotions over the recent death of my cat and wish I never tried to understand in the first place.
Sig Battery depleted. Reverting to safe mode.
What a bunch of BS. China has about 300 million "regular" people, that is, decent incomes and they shop for food at grocery stores. China has ONE BILLION desperately poor peasants and workers, whose lives are not getting better at all. "Eating bitterness" is an idiom that they use to describe their lives. They are as docile as cattle. They won't be clamoring for freedom anytime soon.
Oh, and Newsweek is a discredited, partisan source. Didn't anyone get the memo?
Shutting down free speech with violence isn't fighting fascism. It IS fascism!
There is no "quantum shit going on" that breaks special relativity. Attention world: Once and for all, quantum theory does not break relativity.
How right you are, and I have an elegant theory of quantum gravity that reconciles quantum mechanics with general relativity. Unfortunately, my proof is too large to fit in this forum post.
Socialism: a lie told by totalitarians and believed by fools.
It works like this. You put a red and a blue shirt in a bag. You and Alice close your eyes. You each take out a shirt and put it in a briefcase. Then you both go on a trip.
When you get to the hotel, you open the briefcase and you have a red shirt. You know Alice's shirt is blue. The next question is, so what?
As you can see from the example, you essentially pre-loaded the answer before you went on the trip. It's not real-time communication when you hand somebody a sealed envelope and walk away.
Unfortunately, my proof is too large to fit in this forum post.
Is it really too large, or are you just afraid that once your theory is observed it will no longer hold?
"I don't care about the Constitution!" --Bill O'Reilly, November 17, 2009
Half of it nobody understands anyway.
"I think I can safely say that nobody understands quantum mechanics." --Richard Feynman
"I don't care about the Constitution!" --Bill O'Reilly, November 17, 2009
How did this get moderated up? This poster clearly has no idea what he's talking about.
The whole point of quantum entanglement is that prior to the measurement, there's no basis in which the state is definite. This means it's not just that "you cannot predict which of the two [states] you will measure"; the whole point is that there is no defined classical state the system is in. There's no classical analog for that, so it's really hard (maybe impossible?) to explain without math.
If you don't even know the most basic stuff about quantum mechanics (as is clear from the post), please educate yourself before writing about it or even moderating stuff about it.
Except it's not quite like that.
You and Alice put two shirts in a bag, shake it up, close your eyes, and you each pull out a magic mixed-up shirt which cycles through the color spectrum at random varying speeds (but the same speed on each shirt) until you look at it, at which point it stops cycling on one particular color, and the other stops cycling on the complementary color. You put your shirts in your respective briefcases and go on your trips, and when you get there, you open your briefcase and see your shirt has stopped on red. So now you know that if Alice looks in her briefcase, she will see her shirt has stopped on cyan.
However, the question is again, "so what?"
You don't get to decide whether the shirt is red or blue when you look at it (since the speed it cycles at varies randomly, so you can't very well time it or something), so it's not like you can send a "cyan" to Alice for a "0" and a "red" for a "1". Likewise, when Alice opens her briefcase and sees a cyan shirt, she doesn't even know if you have looked at your shirt or not yet; her shirt might have stopped flashing and just landed on "cyan" by chance when she looked at it (making your shirt stop at "red"), or you may have looked at your shirt and seen "red", making her shirt stop right then too on "cyan".
The only thing that's interesting about these synchronized flashing shirts is the fact that when one stops cycling the other stops at EXACTLY the same time no matter how far away they are. We only know this because when you and Alice do this over and over again and then compare your notes afterward, you always find out that your shirt stopped on one color and hers on the complement. That's interesting because if there was any time delay between one stopping and the other, you would expect the hue-difference between the two shirts to vary with distance: at close distances you'd get close to complimentary colors because they stop at close to the same time, while at larger distances the second shirt would stop slightly later making it slightly off from complementary. And of course if there was no communication between them at all, there would be no correlation between what color you see and what color she sees. But you always see red when Alice sees cyan, and you always see yellow when she sees blue, and you always see green when she sees magenta. Which indicates that anybody looking at either shirt not only stops that shirt but also the other shirt instantaneously.
Which isn't of any practical utility, however, for the reasons described two paragraphs above. But it sure as hell is weird, isn't it?
-Forrest Cameranesi, Geek of all Trades
"I am Sam. Sam I am. I do not like trolls, flames, or spam."
Okay, I'll bite.
So just because you measure the speed between them as c doesn't mean they are each moving at half-c. They are still both moving at c, in opposite directions, for an effective 2c with regards to their eventual position.
No. Your conclusions stem from a fundamental misunderstanding of relativity. It makes no sense to talk about "eventual position" in the way you are, because it requires talking about an absolute time. There is no absolute time. You may have heard this sentence being thrown around before in special relativity, but perhaps you haven't appreciated the full meaning of it.
Let's talk about "eventual position". What you're saying is, we measure the positions of A and C, then wait some time t, then measure their positions again, and, lo and behold, if we divide the distance travelled by the time taken we are left with the impression that A and C are moving apart at 2c. This is true if you measure t and the distance in B's reference frame, but not from A's or C's reference frames, even though these are equally valid.
Once again, there is never one way of looking at things that is just a little bit "truer" than the others, even if your intuition may tell you that, since B's reference frame is at rest, it should provide a less distorted and more objective measurement than A's/C's. Truth is, you could look at the same problem in a different way, where A is at rest. Then B is moving away from it at nearly-the-speed-of-light, and C is moving away at even-more-nearly-the-speed-of-light, at a speed defined by the equation on this page.
We have no definition of which of the above observations is the "correct" way of looking at things, because they are physically indistinguishable from each other. They are, in fact, the same thing; different realities exist for different observers, which is why the name "relativity" is so fitting.
Here's a better example. The furthest objects in the universe are about 13b light-years away. The light they emitted 13b years ago is getting to us now. Do you think, in the past 13b years, that they haven't moved any further??
Sure, 13b light-years away must mean that a photon arriving on earth right now must have been emitted 13b years ago, right? From our perspective it does. From the photon's perspective, it made the journey in less than the blink of an eye. Does this mean the photon travelled many multiples of the speed of light to get here? No, it just shows, once again, that different realities exist for different observers.
Of course I didn't RTFA.