Photon Pair Coupled in Glass Fiber 91
Trachman writes: Austrian scientists have discovered a way to couple photon pairs. When two identical photons are coupled and the phase of one is changed, then thanks to the magic of quantum mechanics, the phase of the other photon also changes (abstract). Scientists predict this can advance quantum optics and quantum computations, taking us a step closer to having data transmissions secure from the nosy agencies of the world.
If any of you have expertise in this area, could you share your thoughts on the essence of this discovery and its associated potential practical applications?
If any of you have expertise in this area, could you share your thoughts on the essence of this discovery and its associated potential practical applications?
Naive optimism in headline (Score:4, Insightful)
Step 1. invent new process that *potentially* could thwart nosy droppers of eaves
Step 2. Process is so expensive and difficult to implement, said agencies are likely to be the only users.
Step 3. Post to slashdot.
People need to wake up and realize that privacy is dead, and ubiquitous violations of personal privacy will soon become the norm.
Your grandchildren will think you a bit 'off' for being of the opinion that privacy is a good thing.
You get what you ask for (Score:1)
Lets decide not to have any secrets while were at it.
Re:Naive optimism in headline (Score:5, Interesting)
Actually, it is even worse: "quantum modulation" is complete BS as networking technology and cannot scale to any real-world WAN networking, except on dedicated links. Why this nonsense gets touted every time is a mystery to me. In addition, what was done so far on dedicated links got broken. It is also not needed at all, as it is so slow that all you do with it is transfer a symmetric encryption key and then you use a conventional VPN. The key exchange is not a vulnerable part of a VPN link, at least if done right. So, in practice, this stuff does not scale, cannot be routed and is not increasing security anyways.
As to privacy being dead, that is a completely unrelated issue, and it is untrue. Strong encryption works. You do have to use it and you do need to invest at least a few days to find out how to use it right, this is not a "single click" problem. (Well, almost nothing is a "single click" problem, but people are stupid and believe the defective things they get delivered as "single click" would actually be beneficial.)
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Really? This is not clear to you? I guess you will encounter a lot more "bad terminology" if you already fail at something this clear and obvious.
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i don't see how this can be used for anything but a dedicated link
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In theory, optical routing. But there are likely unsolvable practical problems. And even if feasible, it does not do anything for security and it would drive cost up massively.
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Well, if you did actually understand crypto or mathematics, you would know that real-world properties like security cannot be proven mathematically. The rest of your statement is of similar insight-less quality. Really, read up on mathematics and crypto and stop claiming nonsense.
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Dedicated links are a special-purpose application with a very small niche-market. As such, they are not going to do anything for most people.
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Can you read? Have you seen this sentence in the OP: "Scientists predict this can advance quantum optics and quantum computations, taking us a step closer to having data transmissions secure from the nosy agencies of the world." ?
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Re:Naive optimism in headline (Score:5, Interesting)
We don't get to decide. There are no serious privacy oriented options left in the marketplace. Privacy is about as hopeless as buying stuff not-made-in-China.
However, if you find that to be offensive, feel free to create misleading information to poison the various databases about you. The nice thing about companies collecting and reselling information about everyone is that they're so gullible. Just be reasonable enough that the new data doesn't get flagged and omitted. If you're a "Fry Technician" at a Fortune 500 company's franchisee, you may want more than one hop between now and your aspiring Bruce Wayne persona.
Depending on how much free time you have, or how much you just like to game the system, you can do things from provide grossly inaccurate income information to those that ask, to having one or more businesses (or hobbies looking like businesses), or creating new people. The easiest, legal way to create fictitious people is "authorized users" on a corporate credit card account. Anyone willing to pay a yearly fee can open a corporate account, then add anyone they want with little more than a name. As long as you use your fake people for legitimate transactions and pay your bills, there's nothing illegal about it.
Back on topic, hopefully developments like this can later be turned into more secure communication technologies that can be used after the advertising&data-merchant economy collapses.
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I use this to track where my information comes from. Salutations such as Professor, or minor mispellings work wonders to reveal the path of crumbs your information left for businesses to follow you.
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An intelligent, but insane friend used to rot13 the name of the information requestor, add vowels as needed and use that as the name provided. That made the source readily apparent. However, this was back in the 90's. I'm not sure if the post office would deliver mail to hundreds of different names now that the mail traffic is captured, or just flag you for reeducation.
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Far less intelligent me got the idea when I applied for Sally Struther's Firearms repair course and they misspelled the junkmail as a result of that for years!
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There are no serious privacy oriented options left in the marketplace. Privacy is about as hopeless as buying stuff not-made-in-China.
When you say "no options" and "hopeless", it is because like everyone else, you must be giving price the highest priority. It is just like things not-made-in-China, you just have to pay more and expect to be dealing with smaller companies and not grabbing stuff off a shelf in a Walmart. At least the people who don't care much about privacy will admit that they are choosing other options because they care more about price.
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the article and blurb both hint at instant teleportation of information.
someone could shed light on why this is isn't so? I mean, someone with more than mumbo jumbo?
Re:Naive optimism in headline (Score:5, Informative)
Here's how collapse of the waveform works. If you take a measurement, you will get a value.
1. The value you get is completely random to you.
2. You cannot in any way choose the value.
3. You cannot know, by reading it, if anyone else has already collapsed the waveform, or if the value you're getting is new.
4. If someone does collapse the waveform, however, when the other side tries to measure it, they'll get the same value - instantaneously.
The problem with trying to use this as some sort of instantaneous information teleportation system is that while it is instantaneous, it's not sending information. Your reading it does not give any information to the other side. You don't choose the value and they can't tell that you've read it. All they get is random noise.
It is, however, potentially valuable for cryptography, in that you can simultaneously generate the same one-time pad in two locations without any snoopable channel, which you can then use to encode or decode data. The data still has to be sent by conventional means - as mentioned above, you're not sending any information by measuring quantum states, the other side has no clue what you've done or not done - but the pad itself is perfectly random and unsnoopable.
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The problem with trying to use this as some sort of instantaneous information teleportation system is that while it is instantaneous, it's not sending information. Your reading it does not give any information to the other side. You don't choose the value and they can't tell that you've read it. All they get is random noise.
In a sense there are ways to use it to send information, or to copy information onto a target system from something on the other end of communication link. But they all involve the random component, such that no matter what someone does at the other end, the signal will look like the same random noise to you on this end. The key to such schemes that use it to send information or teleport states, is you need the other ends measurement, and take actions based on it. So for the example of sending a state to
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Step 4 is the usual explanation, but it's important to note that it contains an interpretation as to what happens. The most you can actually say is that the other party will get a value which, when the two results are later compared, is found to be the same. For my money, and especially given just how weird QM is anyhow, there's a lot of wiggle-room in that difference.
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You can argue about interpretation all you want, but that won't change the results predicted for measurements, which is quite rigorously confined by the math of QM. Anything you do at one end cannot change the possible distribution of outputs as seen by a single end. That math is quite specific about this, with no wiggle room for interpretation. The only way for things do to be different is if QM was fundamentally wrong.
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That's teleporting information in the same way that writing down, "At 3:00 I'm going to do X, at 4:15 I'm going to do Y, at 4:50 I'm going to do Z..." on a letter and sending it to another party is teleporting information. The steps on which they take actions could just as well have been any source of non-random, pseudo-random, or random data of a reproduceable nature. They could just as well both have, for example, traditional random number generators keyed to the same key. Are traditional random number ge
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Re:Naive optimism in headline (Score:5, Funny)
How does a couple screw in a light bulb?
First you have to shrink them down and get them inside....
Got no clue about coupling in a fiber strand...
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Might help to let some air in the bulb
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Pretty much.[*]
Pretty much.[*]
Facebook should fuck off and die yesterday. Facebook is for retards.
[*] When I say "pretty much", I mean not because it is a telephone per se, but because most cellphones are much more than telephones, and marketed as much more than telephones. If you had said "Does GPS need to be kept turned on all the time" I would heartily agree that it does NOT. But I don't know anybody who DOES keep it turned
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I only turn it on when I expect a call
Do you post your call answering schedule somewhere? What happens when someone wants to get in touch with you during your non-answering hours? Third party voicemail? So much for privacy. So much for cheap.
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it goes to voicemail? You realize that voicemail on cellphones isn't built into the bloody phone right? It's from your provider. Just the same as my voice calls can be tapped so can my voice mail, but a reasonable level of privacy is there unless I'm investigated.
And no I don't. This may be a hard concept for you as you're probably a bit younger than I am, but people do not need to be able to talk to me at all times of the day no matter where I am. 99.99% of the time it is never an emergency that I really wished I got that phone call.
You know, once upon a time, people didn't have cell phones, just regular ones. When you called, they were simply 'not home' and you had to wait until they called you back, or you had to just try again another time when you think they might be home.
I lived in that once upon a time, before cell phones and answering machines... well, before the cassette tape answering machines anyway. So I do realize that voicemail isn't built into the cell phone. That's why I said third party. So what kind of phone do you have that has two weeks of standby time?
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Step 1. invent new process that *potentially* could thwart nosy droppers of eaves
Step 2. Process is so expensive and difficult to implement, said agencies are likely to be the only users.
Step 3. Post to slashdot.
People need to wake up and realize that privacy is dead, and ubiquitous violations of personal privacy will soon become the norm.
Your grandchildren will think you a bit 'off' for being of the opinion that privacy is a good thing.
Don't be silly.
Privacy when talking at distances greater than 10 feet was something new that only occurred just recently in history. That may be dead for now, temporarily at least. But you're more than welcome to walk out into your backyard and chat.
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Privacy is dead? At the minimum, photons can have their privacy.
Look at the topic the other way: the world that we know does rely on the privacy of quantum unpredictability, the idea that the photon spin cannot be snooped without altering it. The same world that you know without privacy in what quantum particles are doing would be behaving very differently, no need to explain if one has some familiarity with quantum mechanics.
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People need to wake up and realize that privacy is dead, and ubiquitous violations of personal privacy will soon become the norm.
Absolute hogwash.
The moment privacy actually became dead, so would freedom. You definitely, indisputably cannot have that both ways.
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Or people could wake up and invoke tried and true methods of changing the practices of powers that are against privacy, liberty and freedom.
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What is wrong with all you people? Stop using the Internet for exchanging keys! Make a 2048 bit or so secret key, go and physically hand it to the person you want to communicate with, then encrypt to your hearts content - basking in the certainty that your communications is not being intercepted by said agencies.
If 2048 does not seem strong enough, use more. At some point it becomes impossible to brute force crack it.
Key exchange is the bane of security - STOP USING IT. Do NOT depend on it for anything i
News for nerds!?! (Score:3)
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http://arxiv.org/pdf/1403.1860.pdf [arxiv.org]
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Have to agree. This is on the scale of "That old lemur we found could be _the_ missing link in human evolution." Which one of the 1000s of missing links?
Can't blame the guy (who obviously worked hard) for trying to make his work sound interesting. But it's significance is that it may be one of the lower steps in someone else's future ladder.
Equation (Score:2)
If any of you have expertise in this area, could you share your thoughts on the essence of this discovery and its associated potential practical applications?
((expertise in QM) + (expertise in photon coupling)) x (reads /.) = constant
The Summary is Wrong: Photon AND Gate? (Score:5, Informative)
It's not advancement in quantum communications, it's an advancement in quantum computation.
The potential practical application... it resembles an AND logic gate function, with photons!
This could be a game changer (Score:2)
We might be seeing a major milestone towards the march to quantum computers. Getting 2 photons to interact with each other via a single rubidium atom is a big step. The process still has high noise but I think that can be overcome, but wow, strong interaction between photons.
It's an efficient photonic switch. (Score:3)
What it 'means' is that we are a step closer to optical switching - i.e., optical computers.
The important aspect of the work, as I see it, is that the switch is activated optically also, and the complexity of the switch is low (allowing it to be manufactured easily).
However, I'm no expert in the field. I just read the article, and am geek enough to read /.
Sorry to be pedantic, but.. (Score:2)
Shouldn't the headline read "scientists have discovered a way to couple photons into pairs"? The original "scientists have discovered a way to couple photon pairs" makes it sound like the photons are already paired and those pairs can be further paired.
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Media and the Copenhagen interpretation (Score:5, Informative)
Only 42% of quantum physicisists [preposterousuniverse.com] would agree with the statement in the summary that "When two identical photons are coupled and the phase of one is changed, then thanks to the magic of quantum mechanics, the phase of the other photon also changes", and 40% of them would actively disagree. While the mathematics and measurement predictions of quantum mechanics is quite uncontroversial, the interpretation beyond that is a topic of much debate (much of which belongs in philosopy rather than physics).
The summary is using one such metaphysical interpretation, called the Copenhagen interpretation [wikipedia.org], which has more "magic" than most (spooky, faster-than-light action at a distance; wavefunctions that collapse when I, the Observer, looks at them, but not when anyone else does), and might be the most confusing one to the public (though admittedly, all the interpretations are confusing to some extent).
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Maybe you can help me out since you seem knowledgeable on this stuff.
I've always wondered if there's a possibility that quantum mechanics is simply our system for making sense of things we don't have the ability to measure, and that it might not actually reflect the micro-scale actions going on. As an analogy, 200 years ago we didn't know about the atom because of insufficient tools to develop and test the hypothesis. Now we a fairly decent ability to resolve tiny particles but are severly limited in this
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That's the 'hidden variables' question, and currently there's no way to answer it.
However the 'spooky action at a distance' handwavery explanation of the Copenhagen interpretation is not an indispensible part of the Copenhagen interpretation. One can simply observe that when one of a pair of entangled particles is measured, the state of the entangled particle is logically constrained rather than teleported to its position. And the "measured" portion can be dispensed with as well if you understand that the
Re:Media and the Copenhagen interpretation (Score:5, Informative)
I think it is important to distinguish between three things here. The theory (the equations and predictions of measurements), our interpretations of the theory (what picture of the world we associate with the theory), and the real world itself.
For example, let's say that you need a theory for describing how a hypothetical time-ray works. The observed effect is that physical processes of whatever it is shot at occur at twice the rate as before compared to the rest of the world. This is straightforward to measure and can be modeled exactly using equations. But how should we interpret what happens? One interpretation is that the time-ray speeds up the passing of time for the object it hits. But another, equivalent interpretation is that the ray slows down the passing of time for the entire rest of the world, and protects only the target object from the effect. These interpretations both lead to the same observations, since all we can observe are the *relative* rate of events, but they make different claims about what actually happens. In this case one interpretation is clearly more appealing because it is simpler, but no experiment could distinguish between them. So in some sense the distinction is meaningless.
Similarly, the theory of general relativity, which is our modern description of gravity, can be interpreted as spacetime being curved by the presence of energy, and the curvature affecting the paths of objects. But it is also possible to interpret it as spacetime being flat, but filled with a field of self-interacting, massless, spin-2 particles (gravitons). Both these pictures lead to the same predictions, so in that sense they are the same theory. But they are clearly very different descriptions of reality.
The point of making the distinction between theory and interpretation is that the former can be tested, while the latter can't. The theory of general relativity has been put through a huge number of tests, and it has held up under all of them. Like most theories of fundamental physics it has been tested to exquisite precision, and if it is wrong, it has to be wrong in a very subtle way. But the interpretation of general relativity can't be tested at all. Which one to use is a bit like choosing whether to use a cartesian or polar coordinate system in maths. One might be easier to use or prettier in some situations, but they give exactly the same results.
The same applies to quantum physics to perhaps an even greater extent. Quantum Electrodynamics [wikipedia.org], one of the building blocks of the standard model of particle physics [wikipedia.org], may be the most precistly tested theory in science [wikipedia.org]. The archetypical example is the anomalous dipole moment which is correctly predicted to 14 decimal places (all the ones we could measure so far). So the theory part of quantum physics is trustworthy. It may not be 100% correct, but it is pretty damned close. But there is a plethora of interpretations of quantum physics, and these are completely uncertain - we can't tell them apart because they are mathematically equivalent and hence all make the same predictions. Each one corresponds to a different real world, but we can't tell which one it is.
Electrons bound to atoms are relatively simple quantum systems, and I don't think our ability to measure them is the limiting factor. It sounds like you are arguing for a Hidden Variables [wikipedia.org] description of the electron, where a point-like electron moves around the nucleus in an well-defined particle orbit like a planet, and it only looks like it's this complex non-local wavefunction (electron cloud) because it moves to quicky for us to resolve its actual orbit. The good news is that it it is possible to interpret standard quantum physics that way [wikipedia.org]
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There's several experiments that can be done (e.g. Young's Two-Slit, or explaining how a diffraction grating can reflect light) that very clearly demonstrate that reality is behaving in a quantum mechanical way and the resul
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Thanks, I wondered about that! I had thought that it was more like "When two identical photons are coupled and the phase of one is *measured*, then thanks to the magic of quantum mechanics, the phase of the other photon has also been *measured*." Are these statements equivalent?
believe you must (Score:1)
The magic is still strong in Austria .And funding you get for headlines....
Very Good Children (Score:2)
Very good, Children. You have made the next step towards understanding our instantaneous communications and teleportation device methods for traveling from the stars to visit you. Soon we will welcome you to the Galactic Community.
Your next step is to quell your war like tendencies so we can let you out of your playpen.
good for science, not so good for privacy (Score:1)
What this means in practical QIS terms (Score:2)
Better quantum information channels would also help with qubit teleportation.
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Didn't get the links properly in:
http://www.technologyreview.co... [technologyreview.com]
http://www.wired.co.uk/news/ar... [wired.co.uk]
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I assume this was sarc. But if not, the point is that the conjoined particles aren't even near each other.