Quantum Teleportation Achieved Over 16 km In China 389
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."
Wait, does this mean... (Score:2, Funny)
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No, even quantum entanglement does not transmit information faster than the speed of light.
Re:Wait, does this mean... (Score:4, Interesting)
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Neither does light. What's your point?
Re:Wait, does this mean... (Score:4, Informative)
Light can travel at the speed of light, things with matter can't.
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However, you cannot fully control what information is teleported. You have to [i]traditionally[/i] transport two "bits" of information to complete the teleportation.
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Information is strongly related to energy (perhaps it would be better to say information is useful energy) and energy and mass look the same if you squint at them.
It's a bit backwards to say that "information can't travel faster than the speed of light", however, as light moves at varying speeds (yes, even in a "vacuum"). It's much better to say "light in a vacuum travels very nearly at the maximum speed of information". It's the speed of infomation that's the primitive here, light is just bounded by it,
Re:Wait, does this mean... (Score:4, Interesting)
Clearly light and time are directly related phenomena. I don't think there's a third phenomenon ("speed of information") capping them both. After all, objects are free to move faster than light in relation to one another. The headlights and tail-lights of your car emit photons at c in opposite directions. The speed difference between them is clearly some approximation of 2c. To suggest otherwise would imply that they are somehow physically linked, which they are not. But your measurements are bounded by time, putting an effective cap on the speed you can observe.
Thats not how relativity actually works. Two objects cannot, in fact move apart from each other faster than the speed of light.
A C
If B sees A and C each moving away from it at nearly the speed of light, that just means that A sees C moving away at even-more-nearly the speed of light. Funky, eh?
Light moves at a speed limited by the impedance of the material it is travelling through. A vacuum is nearly the lowest impedance possible (but you can go slightly lower), but is nowhere near 0. Why does space have such a high impedance that space travel is impractical? The information speed limit would be my guess.
Re:Wait, does this mean... (Score:4, Informative)
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 [ucr.edu].
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.
Re:Wait, does this mean... (Score:5, Informative)
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m1014 eV is close enough for my day to day needs.
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If your statement is true, then I'm back to square one on understanding this "entanglement" thingie. Actually, I never really quite made it to square one, but still...
However, I'm not quite ready to take the word of anyone with a Slashdot UID over 3 digits and without a PhD in Physics. I know I wouldn't take my word for anything, and after a cursory reading of your last 50 comments, I'm comfortable in my assumption
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A Stephen Hawking model programmable calculator?
Nah, I think I'll stick with one where I can use my fingers.
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If your statement is true, then I'm back to square one on understanding this "entanglement" thingie.
As far as I know, the problem comes down to measurement. The basic idea is that you can entangle two photons (put them both into superposition states) and then move them far apart from each other. At this point you have two photons in an "unknown" state. If you measure one of the photons the superposition will collapse and the other entangled photon will instantly move out of superposition and into the alte
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Knowing when to observe it doesn't make a difference. The problem is that if Alice observes and sees "down", then she knows that Bob's observation (whether it was before hers or after!) will be "up", but this hasn't conveyed any information.
The measurement is symmetric with respect to each end. In fact it's not even defined which measurement occurs first , if they both measure at a close enough time that the events are not in the same light-cone in spacetime.
superluminal communication problems and ??? (Score:3, Interesting)
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 measurin
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In retrospect, I should have said measure or not measure in a particular way. So Bob is always measuring groups of photons, and Alice continually shifts the way she measures groups to send a message. You are correct that whoever measures thus ends the entanglement UNLESS they do it in a way that doesn't allow them to get any information. Take for example a variation on the quantum eraser experiment (I chose this one because it has a very intuitive diagram and IMO is a fascinating experiment):
http://en.wi [wikipedia.org]
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Are you sure? Einstein thought it was possible, see wikipedia for the Einstein–Podolsky–Rosen paradox.
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Re:Wait, does this mean... (Score:5, Funny)
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.
Quantum Gravity Proof? (Score:5, Funny)
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?
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I don't see this at all. I can certainly use photons to send information, and last I heard most people are going with the idea that photons don't have mass.
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If it hasn't got mass then it's possible for it to beat the speed of light.
No, a particle with zero mass can move at exactly the speed of light. Remember that photons have zero mass. Moving faster than the speed of light requires a particle with an imaginary mass. Such particles have already been named "tachyons", though they haven't been observed, and may not be possible to observe by any detector moving slower than the speed of light.
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Information can't travel faster than light you moron
Then can you please explain what TFA is all about?
Re:Wait, does this mean... (Score:5, Informative)
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.
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the whole point is that there is no defined classical state the system is in.
Are you sure [stanford.edu] about that [rutgers.edu]?
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No, what you say is the current theory. The experimental results are precisely what the grandparent poster described: that you cannot predict which of the two states you will measure.
The experimental results agree completely with the current theory: you cannot predict which of the two states you will get from the measurement. If that was all the grandparent had said, I wouldn't had bothered answering.
The problem is, he seems to think the entangled state is such that you can fix probabilities in one end with a measurement, and then the measurement in the other end would depend on these probabilities. This is complete bunk, regardless what interpretation you subscribe to. No one serious e
Obligatory (Score:2, Funny)
Re:Obligatory (Score:5, Insightful)
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).
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Yea but. (Score:5, Funny)
Unfortunately, what they transmitted was an email for Vi4gra, using an open wifi connection at a Starbucks 10 miles down the road.
Lightspeed limited, not an ansible (Score:5, Insightful)
Before you think this is awesome, this is not an ansible, information is transmitted at lightspeed only.
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ansible [wikipedia.org]
Next time, define the terms yourself, you insensitive clod.
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Asking people to look things up for you in an age where doing it yourself literally means putting your finger down, moving your hand one inch, and putting your finger down again, is pretty fucking contemptible.
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You must be new here.
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Note, however, that only information is sent, not the actual "item".
The implication, of course is if you can "transmit" an arbitrary item, you can, by definition duplicate it. So, when we have this technology, you will be able to "have your cake and eat it too".
Oddly it will also be the most altruistic, or selfish thing you can ever do. Consider; altruistic - you send a "copy" of yourself to do something cool. selfish, nasty task? send a "copy", not "you".
This might be
Re:Lightspeed limited, not an ansible (Score:4, Interesting)
It happens faster than the speed of light, but it isn't any use without extra information which can only be sent at light speed. You could use it to send secret messages since the state is instantly transferred and cannot be intercepted on the way and then the extra information can be used to get the data.
What is the nature of the extra information? (Score:2)
Is it possible to generate the needed information in advance?
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Given your username, I'll believe you.
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Yes...but you can't use it to transmit any information.
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Re:Lightspeed limited, not an ansible (Score:4, Informative)
Yes, information can only be transmitted at light speed. (Except [gravity] information [..])
No, that would break the universe. Gravity is also limited by by c. http://en.wikipedia.org/wiki/Speed_of_gravity [wikipedia.org] says: The speed of gravity in general theory of relativity is equal to the speed of light in vacuum, c.
Re:Lightspeed limited, not an ansible (Score:5, Interesting)
Also, please do not just say "Your wrong, GTR says that can't happen", you would be "citing authority" and it really kills the validity of your rebuttal. Sort of like saying "God exists because the Bible says so". Please explain WHY its wrong, as in cite what portion of GTR says it can't happen so I can read it and see where how I went wrong.
According to General Theory or Relativity, as defined in the link you posted, if a mass were to suddenly appear at a location in space-time, say in the forward Lagrange point of Jupiter's orbit, it would take X amount of time before the gravity from that mass would affect the orbits of the other planets in the Solar system. X being equal to time it would take for light to travel from the location of the mass to the rest of the planets in the Solar system.
Have I got it right so far?
But my understanding is that, according to GTR, gravity is caused by the deformation of space-time by a mass. So the mass that suddenly appeared would deform space-time around it, thus imposing a gravitational influence on all objects in range.
Here is what has me going "wait, what?"
Also according to GTR space-time can expand/contract at speeds greater than that of c in a vacuum, as described in the "inflation" theory [wikipedia.org] of the early universe and Alcubierre's [daviddarling.info] "warp drive" theory. Since the mass deforms space by "stretching" it wouldn't that mean that the influence of a mass could affect an object at a distance in less time than it would take light to travel that same distance? Since the "fabric" of space-time could alter faster than light can travel across it.
I'm hoping to get some insight into how I could be wrong, because based on what I know I can't see any reason why it can't happen. It could explain why we haven't detected gravity waves using interferometry, if the gravity wave, a distortion of space-time was moving faster than light it wouldn't be able to affect the phase of the light beams.
Thank you in advance to those who actually provide some useful info to help me improve my understanding.
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If gravitational waves could go faster than the speed of light, that would break causality. This means that you could find some reference
Re:Lightspeed limited, not an ansible (Score:5, Informative)
Yes, information can only be transmitted at light speed. (Except information pertaining to gravitational fields, which must be transmitted instantly over vast distances in order for planets and moons to stay within stable orbits. Run the numbers for yourself -- see if you can get the planets to stay in orbit when the force points towards where the *current* light-speed gravitational waves say the massive object is.)
Who modded this "interesting"? It is nonsense. The use of the term "force" in the context of gravity indicates that the poster is is talking about classical, Newtonian gravity. And there is no speed-of-light-limit in Newtonian gravity. Neither is there anywhere else in Newtonian mechanics.
You want to do gravity relavtivistically (i.e. correctly, in agreement with actual, modern-level observations) you'll have to use general relativity. Which just so happens to work just fine. You'll find that there's no "force" (or other absolute vector) in there at all. The whole thing is essentially geometry-free, only the differential of any vector ever plays a role. As it should be, in a properly relativistic physics.
NOT over a free space (Score:2, Funny)
Not until they do it over the USA or even France, but not over China.
I don't get it (Score:5, Insightful)
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.
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Re:I don't get it (Score:5, Informative)
- Charlie entangles Particles A+B
- Charlie sends Alice Particle A over fiber
- Charlie sends Bob Particle B over air
- Alice measures A and sends Charlie information about measurement (classic part needed for actual information transfer)
- Charlie sends classic information to Bob
- Bob measures Particle B, combines result with classic information, and voila, Bob can reconstruct the information "sent" by Alice
Clearly no way to transfer information securely or fast, but a proof that entanglement in Particle B for Bob can survive long transfer through air.
Classic information? (Score:2)
I still don't get it. Could you use a car analogy?
How does time work here? (Score:2)
Sure you can determine the state of a particle. You can do something that will change its state in a predictable way. Then the other particle, which you haven't changed, changes at the same time.
Which brings us to the question of Relativity: Since there is no such thing as simultaneous time in the universe, per Einstein - that is, what's simultaneous from one perspective is sequential from another - when does the untouched-but-entangled particle change state to match the one we've acted on in a determinativ
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As far as I know (very little, please correct me if I'm wrong), you can't neither predict nor influence the outcome of measurements, but you can be sure they will be the same at both ends, unless someone is eavesdropping in the middle. The flow of measures can then be used as a one time
Peer Reviewed (Score:5, Insightful)
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.
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Re:Peer Reviewed (Score:5, Informative)
The work was done by Jian-Wei Pan, one of the leaders in the field and a very impressive researcher. You can bet that the result is accurate if his name is behind it. Furthermore, it's being published in Nature Photonics. Besides, the result is impressive, but not ground breaking. Extending the distance of the protocol requires some fancy techniques and a good deal of skill and expertise, but the results aren't surprising.
What, no tradtional signal? (Score:2)
In what way are photons travelling down a fiber not a traditional signal? Sure, they are entangled, but you still have to ship photons around.
Contradictory (Score:3, Informative)
Please mod parent up (Score:2)
You still need a classical signal. Information still cannot be transmitted faster than light.
It's possible there are esoteric uses for this if it could be scaled up dramatically in terms of the sophistication of the state transmitted, and this could matter for quantum computer communication some day, but I fail to see any real use for quantum teleportation today.
I do have a BS in Physics, but that was 15 years ago and I have never done physics professionally - I got sucked up by the nice pay and abundant j
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Information still cannot be transmitted faster than light.
Sigh...subspace transmissions, hello???
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Way I read it is that you need a traditional channel to get one of the photons to the other location. Once you've done that, change made at the first location are realized at the second station without the traditional channel.
ie. You want to hear me a mile down the road, so you ride down the road with a walkie-talkie. Once you get there, we are able to communicate without a new radio being sent to you every time.
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Except each entangled pair is one-use only. You measure the state of one half of it, which instantly sets the same state in the other pair, and then they're no longer entangled (due to you having observed).
Also you can't predict or set the state of half an entangled pair, only measure it, causing the waveform to randomly collapse. The only thing this gets you is secure transmission of a random sequence (many entangled pairs) of states, which you can then use as a one-time pad/key for conventional encry
Have they now... (Score:2, Informative)
"Scientists in China".
Think I'll be waiting for independent verification of this one then...
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This research group happens to be very well respected and is a leader in the field. They are, without question, some very good scientists.
In a few years... (Score:2)
What if a photon moved out of superposition (Score:3, Insightful)
Re:Progress.. (Score:5, Insightful)
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.
Re:Progress.. (Score:5, Insightful)
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. [newsweek.com]
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Newsweek is mistaking transients for a steady state. The middle class and freedom form a self re-inforcing feedback loop. The more middle class, the more freedom, the more freedom, the more middle class, etc.
What's happening in Indonesia, Brazil and Russia as it is portrayed is the middle class advocating its own destruction. Freedoms will be taken away and the middle class will shrink as a result. So there may be a middle class in these countries now, often fueled by things like oil as opposed to a true fr
Bullshit article (Score:4, Insightful)
"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.
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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.
Well, that's always been the assumption, anyway. But apparently things are playing out a little differently in China. [newsweek.com]
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Give it time. They are in no way near the level of *average* economic security that we enjoy in the West. They are already getting inflation, which will push up the cost of the goods they produce, but increase the average salary. They are going very far, very fast, but they still have a ways to catch up with the US and Europe in the way of average income.
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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.
Well, that's always been the assumption, anyway. But apparently things are playing out a little differently in China. [newsweek.com]
That article's conclusions were misleading and implied that the middle class may not be interested in political freedom anymore. But all of the studies it discussed stated that the middle class still values political freedom, but that it values it less than creature comforts.
This highlights a new tactic by authoritarian regimes in recent decades. They have realized that it is easiest to keep a critical mass of the population comfortable in order to maintain control.
That doesn't mean they aren't primed
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That doesn't mean they aren't primed for revolution. It just means that revolution isn't worth it for them... yet.
The problem is, that statement is just as true for the United States [rasmussenreports.com], and not a few other western nations.
All you're doing is restating the fundamental political question faced by all societies - will upsetting the current order bring a more favorable situation than continuing to tolerate it? And I have seen no evidence the Chinese people have decided that question in favor of revolution, any more than the US has.
Less so, actually. If you consider the results of this poll [pewresearch.org], it appears the Chinese are a lot m
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Re:Progress.. (Score:5, Informative)
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?
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They stole the idea from Star Trek.
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The idea of any organism is to multiply and spread to new areas, whether we are talking about humans, viruses, bison or trees.
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I thought it was a musician who plays any type of organ.
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Aren't they supposed to explain it all on TV Sunday night?
Re:Philotics (Score:5, Funny)
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.
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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.
Re:Philotics (Score:5, Funny)
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.
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Re:Philotics (Score:4, Funny)
Not anymore you don't.
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That's because in China they just make up results like this to please political bosses.
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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
Re:Philotics (Score:5, Informative)
Half of it nobody understands anyway.
"I think I can safely say that nobody understands quantum mechanics." --Richard Feynman
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still have to deal with the speed of light.
Re:This would be interesting for production use... (Score:4, Interesting)
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Now that is interesting.
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Hrm.
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As long as you got 1 bit of communication, you can do anything.
Re:This would be interesting for production use... (Score:5, Interesting)
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.
Re:This would be interesting for production use... (Score:5, Interesting)
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?
Re:This would be interesting for production use... (Score:4, Interesting)
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?
Info can't propagate faster than speed of light. (Score:5, Informative)
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.
Re: (Score:2)
why does it take that long to get it working ? didn't take scotty that long to figure it out ;)
They insisted it be housed in a transparent aluminum case.
Re: (Score:2, Informative)
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.