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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."
... I might stop having Cablemodem issues? Sexy!
Buanzo Consulting - 15 Years of GNU/Linux experience, for you.
http://xkcd.com/465/
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!
Not until they do it over the USA or even France, but not over China.
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."
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.
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.
Why is TFA contradicting itself? A traditional signal is always needed, that's one fundamental principle of quantum comunication.
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
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.
"Scientists in China".
Think I'll be waiting for independent verification of this one then...
If you try to fail and succeed, which have you done?
That's because in China they just make up results like this to please political bosses.
and when you finally have freedom, you then want the government to do everything for you and regulate everything that is not perfect in hopes that the government will make it perfect...then you lose your freedom again.
jsut athnoer menagiensls ltitle psrhae for you to dcoede. Why do we wtsae our tmie dnoig tihs?
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.
Not anymore you don't.
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!
Half of it nobody understands anyway.
Only because "understanding" appears to be highly variable concept depending on field of study. Non-physicists assume that just because a concept cannot be explained in simple (i.e. classical) terms, it has "not been understood". This requirement is foolish. The simplest way (and I'm really oversimplifying here) to see why is to remember that classical physics is a special case of quantum physics. How could you possibly explain everything in the superset in terms of the subset? Paradoxes are the pornography of the pseudo-intellectual.
Could you elaborate?
In that entanglement is the very basis of quantum communication, I'd say it has a fair bit to do with it.
Information still cannot be transmitted faster than light.
Sigh...subspace transmissions, hello???
"The Asian crisis was a turning point in that sense," says Brookings Institution senior fellow Homi Kharas, who studies the new global middle class. "These countries began pursuing liberalization in their own way, at their own pace, and they've done well. Now they see their success as the fruit of their own efforts," even though it was attained under global systems of free trade and finance set up by the West.
When someone is gently tugging your dick, keep your hand on your wallet. China and India have been successful because they did not adapt Western financial values. Ditto for Brazil and any other country who was large enough to avoid being pressured into the Chicago school of self-destructive economics. Since 1980, the Western world has been destroying markets and free trade by eliminating regulations and fairness - the only things that keep a market competitive, just as a vibrant independent press is that only thing that keeps democracies truly free.
China will soundly destroy the American economy because 1) it's still developing and four times our population, 2) it's typically not imperialistic outside it's own borders, and 3) it's not being run by a voting bloc which believes literally that the earth is 6,000 years old.
Our founding fathers decried Europe for being chained by the monarchist traditions and the shackles of dogmatic religious squabbling. Well, guess who the new Europe is. We just traded Monarchy for Corporatism.
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
Measuring at different times doesn't appear to matter (See Wheeler's Delayed Choice experiments). Which is very amazing in itself and an entirely different topic of discussion. The problem is that however you set up your experiment, no practical information is exchanged FTL. Alice could measure the entangled pair at the same interval as Bob, but that doesn't really tell her anything since Bob can't actually cause his entangled particle to have a particular spin, polarization, or whatever they're measuring. It's only interesting after the fact when they compare notes.
So you say well then, instead of using the particles let's use the act of measuring or not to transmit info. If Bob measures his particle he's sending a 0, if he doesn't he's sending a 1. And Alice will see this reflected at her end somehow. But the problem with this, from my understanding, is that everything is going to look random to Alice however she chooses to measure it (or however they agree to ahead of time). Because remember you are looking at individual particles. Again, it's only interesting after the fact when they compare notes.
Now the question I am not sure the answer to, is if they were to use a group of photons and either measuring or not measuring the group as a whole. For example, if you think of the classic double slit experiment, doing something to an entangled set of photons to cause their distant pairs to either form a wave-pattern or a blob on a detector. I don't know if this is possible or not, and it sounds like there might actually be some serious debate about this (see Dopfer experiment)
The sending of this message pretty much inconveniences everyone involved.
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
but no one was there to hear it. Would there still be information? Ah, the philosophy of quantum physics. I know nothing about physics, ever had a class. After reading 238 postings on this topic, I still know nothing but feel like I am in good company.
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."
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.
In the context of special relativity, what does it mean for two things to happen at EXACTLY the same time?