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Deterministic quantum teleportation through fiber channels
- jcwilde 8y agoIs this not the holy grail?
- dsr_ 8y agoThe number one problem with quantum teleportation is the name. It should have been named quantum telegraphy. There would be fewer cranks.
- mishurov 8y agoIt's charming in a way. I nicely alludes to Sci-Fi and confuses newbies.
- friday99 8y agoor even something more descriptive like quantum state disambiguation.
- kgwgk 8y agoHow is that more descriptive? The most natural name would be "replication" (of the quantum state), but given than the original is lost and only the replica survives "teleportation" doesn't look so bad.
- chrisweekly 8y ago"quantum state transfer"?
- abdullahkhalids 8y agoThe original paper [1], written by some of the best scientists of the era, correctly called it "Teleporting an Unknown Quantum State", and nowhere did it use the term "quantum teleportation". Later, in interest of conciseness, the ambiguous term "quantum teleportation" got introduced. It would have been better if "quantum state teleportation" had been used. [1] https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.70.1895 https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.70...
- buboard 8y agobut quantum state is all that can ever be measured about the system so seems a redundant word
- nine_k 8y agoNo mass is teleported, that's the key. A state of one mass is copied to another mass, but no mass is moved in the sense that would invoke General Relativity, as far as I understand. I suppose teleporting a state in such a way that the target mass would change its motion in a significant way ("accelerated") without affecting the source mass is impossible, because it would break the conservation of impulse.
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- FeepingCreature 8y agoQuantum copypaste.
- kgwgk 8y agoRelevant read: "Quantum Teleportation" and other Quantum Misnomers (H. D. Zeh) http://www.rzuser.uni-heidelberg.de/~as3/Teleport.html http://www.rzuser.uni-heidelberg.de/~as3/Teleport.html
- Ws32ok 8y agoNames have the power to guide perception about what they identify. "Quantum teleportation" is as easily misused as that of "dark matter". Is it actually matter? If the answer isn't a definite yes then the term doesn't help long term but maybe it's good enough for now. "Dark energy" is another term. Is it accurate? Maybe. It alse works for plenty of people for now. Both terms assist as long as they help discussion but the lay person easily gets confused and experts can get mislead as well. If you think of it as matter then you design experiments in particular ways. You think about it in those terms. You don't think of it in other ways to the same extent. Quote from Wikipedia: https://en.m.wikipedia.org/wiki/Dark_matter https://en.m.wikipedia.org/wiki/Dark_matter "The primary evidence for dark matter is that calculations show that many galaxies would fly apart instead of rotating". Not exactly a ringing endorsement of matter as real. But as long as it helps the overall investigation then it's ok for now. Calculations can accurately describe reality and guide decisions so why not. "Quantum teleportation" as a term is easily derailed no matter how helpful it describes a portion of reality. Maybe it simply needs a few more words nearby to put the brakes on people's imagination. The map of the place is not the place.
- modzu 8y agoit begins
- thomastjeffery 8y agoPapers like this are so terse. I understand the need to use correct verbiage; but to the layman, this is incomprehensible.
- abdullahkhalids 8y agoWith all due respect, these papers are not written for the layman. They are written for the few thousand people who work in the field or near enough to understand this work. Single results in physics (and science) in general are almost never individually relevant to the public. The public should read either review or meta papers, or they should read the articles/books written by scientists for public consumption. As a physicist, I rarely upvote physics papers on HN, unless there is insightful commentary in the comments. This is not an insult to anyone who is not a scientist - just that jargon is necessary for rapid progress, and understanding jargon requires developing expertise by many years of work.
- copperx 8y agoI think OP was questioning how is this paper fits in an generalist IT/business forum.
- abdullahkhalids 8y agoI totally agree with them that it should not be posted here.
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- krastanov 8y agoThis paper is really not meant for the layman. Even PhD physicists would find it terse unless they are working in the field of quantum information or AMO physics. However, there are many exciting and great resources where anybody interested can learn more about advanced physics. "The Theoretical Minimum" or Feinman's Lecture series are a great long on boarding experience that starts slow but gets pretty serious towards the end. And many researchers have more pop-sci type of blogs and media materials for those that want just a quick fix.
- copperx 8y agoIt's not surprising that the article is in English even though it's an all-Chinese team, because it was published on an English journal. But I can't stop wondering how many years are left before most scientific output is in Chinese. The dominance of English might be over soon.
- abdullahkhalids 8y agoIt took centuries of British colonization to make British English the lingua franca of the world, and decades of American cultural and economic imperialism to switch the default to American English. It is unlikely that a complete switch to Chinese will happen on any shorter scale, if ever.
- TomMarius 8y agoDecades aren't really a long scale, though. 3 decades ago almost nobody in the Czech Republic spoke any English, today it's a common day-to-day language in Prague as many foreigners live there, even the homeless speak good English.
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- PeterisP 8y agoScientific results are primary communication. It can happen in English because lots and lots of non-English scientists worldwide understand English, just as in earlier times it could happen in Latin, French or German. It's pointless to produce articles which don't reach the audience that matters, so your language is irrelevant compared to the language of the audience. I wouldn't expect much (not even most, but even a significant amount) of scientific output to happen in Chinese, even if produced by Chinese authors, until Chinese becomes a very popular second language worldwide which a critical mass of global researchers (e.g. most people who "matter" in a particular subfield) can use. Currently it still has a far way to go - while it's comparable in the total number of speakers (1.1 billion for both Chinese and English according to https://en.wikipedia.org/wiki/List_of_languages_by_total_number_of_speakers https://en.wikipedia.org/wiki/List_of_languages_by_total_num...), Chinese has just 200m secondary speakers compared to 740m of English, and that is the number that matters; not the total number of people but the "marketshare" of how many of worldwide 'educated class' know the language, and English has an extreme headstart in this regard. Any changes would require at least a full generation - new researchers growing up that had learned Chinese because it was widely taught for other reasons.
- lisper 8y agoFor anyone wanting a layman's description of QT: https://blog.rongarret.info/2014/12/quantum-teleportation-demystified.html https://blog.rongarret.info/2014/12/quantum-teleportation-de...
- kgwgk 8y agoI agree that the cartoon that you criticize is confusing. Starting with the first panel, because it doesn't make clear that Alice doesn't know the color/state of her photon. If she knows it's yellow she only has to tell Bob to prepare a yellow photon and there is no need for an entangled pair to make it possible. The whole point of the setup is to be able to "teleport" an arbitrary unknown quantum state. But the following doesn't seem correct: > when Bob receives Alice’s bits, he uses that information to apply one of four transformations to his photon. It is Bob’s action that changes his photon’s state into the state of Alice’s original photon. And that is the only time that Bob’s photon changes state. To recover the state being "teleported" by Alice, Bob has to apply one of the four pre-specified "rotations" (unitary transformations) according to the two-bit message he receives. In fact one of the operations is to do nothing, sometimes the state of his photon is already the state of Alice's original photon. Of course this is true only after the measurement performed by Alice. Previously there was no relationship between the state of Bob's photon and the state of Alice's "source" photon: the probability of the state being the same (or related by one of the three other pre-specified rotations) is essentially zero.
- lisper 8y ago> sometimes the state of his photon is already the state of Alice's original photon [but] this is true only after the measurement performed by Alice No, that's wrong. Alice's measurement does not change the state of Bob's particle. There is no measurement Bob can perform on his particle which will tell him whether or not Alice has performed her measurement or not. Quantum teleportation is no different from regular old EPR in this regard. > the probability of the state being the same (or related by one of the other three pre-specified rotations) is essentially zero. Actually, it is precisely zero. The entire claim that the state of Alice's particle is teleported intact to Bob is actually a lie. What is true is that no measurement can distinguish the state of Bob's particle (B) after teleportation from Alice's original (C). But this does not mean that the particles are in the same state. Before teleportation C is in a pure state, and B is in a mixed state (as is A). The Bell measurement that Alice performs on A and C entangles them, and the result is a three-particle mutually entangled system, plus two classical bits that tell you how to tweak B so that its measurement outcomes are the same as C's. But B is in the exact same (mixed) state after Alice's measurement as it was before. BTW, there is a measurement Bob can perform, not on a single B, but on a collection of B's that will reveal that all the B's are in fact in a mixed state. If you want to go down that rabbit hole, read this: http://www.flownet.com/ron/QM.pdf http://www.flownet.com/ron/QM.pdf
- abdullahkhalids 8y agoIn this work, continuous-variable quantum states are being teleported. The reason they almost-incorrectly call it deterministic is that continuous-variable [1](think analog) quantum states even when degraded by signal transmission errors will always transmit some information to the destination. Qubit (or discrete state) teleportation on the other hand will usually have some probabilistic errors that completely destroy the signal. Therefore, the correct metric to report for analog signals is the fidelity. They do report this as 69% - which is above a certain important threshold - but also fairly low for any practical application in the near future. [1] as opposed to discrete-variable states eg. qubits
- krastanov 8y agoI work in this field and I can not really make sense of your statement. "Fidelity" the way they define it has nothing to do with whether they have a qubit or any other system (infinite dimensional or not).
- posterboy 8y agoThe threshold being, I guess, 1/e which determines the width of a laser, the radius of its beam covering 69% intensity?
- rightbyte 8y agoDo I get this straight: "Quantum teleportation" is like receiving a letter with four pages and then telling another receiver of the same letter which page to read?
- kgwgk 8y agoWith the caveat that the four pages in Bob's letter are not written until Alice does her thing with her copy of the letter and the photon she wants to "teleport". Note also that she doesn't know the state of the photon, which is destroyed as a result of the procedure.