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Here is another article that tries putting in English. http://www.zmescience.com/science/physics/physicists-quantum-photons-08092012/ http://www.zmescience.com

Here is another article that tries putting in English. http://www.zmescience.com/science/physics/physicists-quantum-photons-08092012/ http://www.zmescience.com/science/physics/physicists-quantum...

dandrews 14y ago
Careful with this article. They get it wrong, suggesting the possibility of "instantaneous internet connections". No FTL information transfer allowed, kids.
alecco 14y ago
The author fails to understand the basics of Quantum Teleportation. Think of it this way: Alice has 2 boxes with the same unknown bit, and sends one of those boxes to Bob. When Alice opens her box she can see the value and Bob can see it too. Something like that. Very good for cryptography (think untamperable shared secret keys) and for some cases of parallel computing. Superluminal (FTL) communication would break Special Theory of Relativity. If anybody achieves that it would be an instant Nobel and front page on every newspaper on the planet. Even a mistake like the FTL neutrinos fiasco earlier this year. Tech journalists tend to skim the abstracts and hype it to sell more clicks/ads.
- newhouseb 14y ago
  I'm trying to think of a physical analogy to better understand this: Image you (Alice) have a randomly shuffled (say, by god) deck of cards. You cut the deck in half and distribute one half to Bob and keep the other half (such that by knowing one half, you would know the other). Until either of you look at your respective half-deck, the distribution of cards is in a superposition of all possible distributions (a la Schrodinger's cat). Where the analogy breaks down (thereby illustration what's special about Quantum Teleportation), is that as soon as Alice flips her cards, Bob's cards flip as well (and visa versa). Thus by the time the cards got to Bob, Bob would be able to detect that someone else could have read the cards and thus the information may have been compromised. (This is kind of how I remember quantum cryptography to work, actually). Does this analogy make sense? My physics background is pretty weak...
  - sp332 14y ago
    That's not bad, but with quantum physics you can get better correlations than you possibly could get with classical physics. http://en.wikipedia.org/wiki/Bell_test_experiments http://en.wikipedia.org/wiki/Bell_test_experiments
  - Saavedro 14y ago
    This is really just an illustration of quantum cryptography, rather than quantum teleportation. Quantum cryptography is a method of exploiting quantum effects to create a channel that can be used to transmit classical information in a manner that cannot be eavesdropped. Quantum teleportation is kind of the opposite. It uses a classical information channel in order to transmit -quantum information-, which can't actually be represented clasically. It is actually moving the superposition itself from one place to another. The term "teleportation" is used because the "no cloning" rule (quantum information cannot be "copied") means that the information is no longer in the original location. This is mostly useful in quantum computers, because in order to actually process information it's pretty important to be able to get it from one piece of the machine to another, and until the recent teleportation breakthroughs building quantum computers that could handle more than a couple "qubits" was pretty much not doable.
  - deleted 14y ago
    [deleted]
- marshray 14y ago
  Very good for cryptography (think untamperable shared secret keys) Sounds to me like an incredibly convoluted, fragile, and expensive method of exchanging keys. In what practical way is this better than traditional or elliptic-curve Diffie-Hellman key exchange?
  - beloch 14y ago
    The big difference is that encryption based on computationally difficult (but not impossible) problems (i.e. factoring) should not be used to encrypt information that must remain secure long-term. e.g. Say you have a highly sensitive secret that must remain secret not for just a few years, but decades or centuries. If you encrypt it using a factoring based scheme and then transmit it classically, an eavesdropper could take a copy of the encoded message without your knowledge. Whatever scheme it was encrypted with will then have to stand up to decades of advances in algorithms and computing technology. Quantum computers will probably break most currently used factoring-based schemes (including elliptic) eventually, and there's no guarantee that there exists no classical algorithms that could break such encryption with practical amounts of classical computation either. You should view anything encrypted and transmitted using factoring-based methods as having been broadcast publicly with an unspecified delay. Quantum cryptography is unbreakable in theory, but is not without flaws in practical systems. However, the nature of communicating with quantum states (google the no cloning theorem) means that attacks must be known and used at the time your message is transmitted. An eavesdropper trying to listen in on quantum encrypted communications cannot archive coded messages to attack at his or her leisure. Attacks must be immediately successful or the message will remain secure for all time. So, your credit-card info is probably safe to transmit using factoring based cryptography, since it changes every few years. Your medical records, or where you buried that body, are a different matter entirely!
    - marshray 14y ago
      Whatever scheme it was encrypted with will then have to stand up to decades of advances in algorithms and computing technology. So will the block or stream cipher you encrypted the data with. Quantum computers will probably break most currently used factoring-based schemes (including elliptic) eventually That seems extremely optimistic to me. Given the current state of the technology, it's a little like an astronomer discovering a distant new star and then promising to open suntan parlors from its concentrated rays. Try this thought experiment: For a given set of security and speed requirements, take the money you would spend on a pair of quantum key exchange devices and spend it instead on accelerator hardware for non-quantum ECDH operations. How much longer (and more secure and reliable) can we make the key exchange parameters with this conventional hardware within the same time limits?

Here is another article that tries putting in English. http://www.zmescience.com/science/physics/physicists-quantum-photons-08092012/ http://www.zmescience.com/science/physics/physicists-quantum...

dandrews 14y ago

Careful with this article. They get it wrong, suggesting the possibility of "instantaneous internet connections". No FTL information transfer allowed, kids.

alecco 14y ago

The author fails to understand the basics of Quantum Teleportation. Think of it this way: Alice has 2 boxes with the same unknown bit, and sends one of those boxes to Bob. When Alice opens her box she can see the value and Bob can see it too. Something like that. Very good for cryptography (think untamperable shared secret keys) and for some cases of parallel computing. Superluminal (FTL) communication would break Special Theory of Relativity. If anybody achieves that it would be an instant Nobel and front page on every newspaper on the planet. Even a mistake like the FTL neutrinos fiasco earlier this year. Tech journalists tend to skim the abstracts and hype it to sell more clicks/ads.

newhouseb 14y ago
I'm trying to think of a physical analogy to better understand this: Image you (Alice) have a randomly shuffled (say, by god) deck of cards. You cut the deck in half and distribute one half to Bob and keep the other half (such that by knowing one half, you would know the other). Until either of you look at your respective half-deck, the distribution of cards is in a superposition of all possible distributions (a la Schrodinger's cat). Where the analogy breaks down (thereby illustration what's special about Quantum Teleportation), is that as soon as Alice flips her cards, Bob's cards flip as well (and visa versa). Thus by the time the cards got to Bob, Bob would be able to detect that someone else could have read the cards and thus the information may have been compromised. (This is kind of how I remember quantum cryptography to work, actually). Does this analogy make sense? My physics background is pretty weak...
- sp332 14y ago
  That's not bad, but with quantum physics you can get better correlations than you possibly could get with classical physics. http://en.wikipedia.org/wiki/Bell_test_experiments http://en.wikipedia.org/wiki/Bell_test_experiments
- Saavedro 14y ago
  This is really just an illustration of quantum cryptography, rather than quantum teleportation. Quantum cryptography is a method of exploiting quantum effects to create a channel that can be used to transmit classical information in a manner that cannot be eavesdropped. Quantum teleportation is kind of the opposite. It uses a classical information channel in order to transmit -quantum information-, which can't actually be represented clasically. It is actually moving the superposition itself from one place to another. The term "teleportation" is used because the "no cloning" rule (quantum information cannot be "copied") means that the information is no longer in the original location. This is mostly useful in quantum computers, because in order to actually process information it's pretty important to be able to get it from one piece of the machine to another, and until the recent teleportation breakthroughs building quantum computers that could handle more than a couple "qubits" was pretty much not doable.
- deleted 14y ago
  [deleted]
marshray 14y ago
Very good for cryptography (think untamperable shared secret keys) Sounds to me like an incredibly convoluted, fragile, and expensive method of exchanging keys. In what practical way is this better than traditional or elliptic-curve Diffie-Hellman key exchange?
- beloch 14y ago
  The big difference is that encryption based on computationally difficult (but not impossible) problems (i.e. factoring) should not be used to encrypt information that must remain secure long-term. e.g. Say you have a highly sensitive secret that must remain secret not for just a few years, but decades or centuries. If you encrypt it using a factoring based scheme and then transmit it classically, an eavesdropper could take a copy of the encoded message without your knowledge. Whatever scheme it was encrypted with will then have to stand up to decades of advances in algorithms and computing technology. Quantum computers will probably break most currently used factoring-based schemes (including elliptic) eventually, and there's no guarantee that there exists no classical algorithms that could break such encryption with practical amounts of classical computation either. You should view anything encrypted and transmitted using factoring-based methods as having been broadcast publicly with an unspecified delay. Quantum cryptography is unbreakable in theory, but is not without flaws in practical systems. However, the nature of communicating with quantum states (google the no cloning theorem) means that attacks must be known and used at the time your message is transmitted. An eavesdropper trying to listen in on quantum encrypted communications cannot archive coded messages to attack at his or her leisure. Attacks must be immediately successful or the message will remain secure for all time. So, your credit-card info is probably safe to transmit using factoring based cryptography, since it changes every few years. Your medical records, or where you buried that body, are a different matter entirely!
  - marshray 14y ago
    Whatever scheme it was encrypted with will then have to stand up to decades of advances in algorithms and computing technology. So will the block or stream cipher you encrypted the data with. Quantum computers will probably break most currently used factoring-based schemes (including elliptic) eventually That seems extremely optimistic to me. Given the current state of the technology, it's a little like an astronomer discovering a distant new star and then promising to open suntan parlors from its concentrated rays. Try this thought experiment: For a given set of security and speed requirements, take the money you would spend on a pair of quantum key exchange devices and spend it instead on accelerator hardware for non-quantum ECDH operations. How much longer (and more secure and reliable) can we make the key exchange parameters with this conventional hardware within the same time limits?