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Purdue Builds Quantum-Computing Semiconductor

Posted by timothy on from the odd-bits dept.

Bfaber writes: "According to EET, Purdue has created the first examples of quantum computing in a semiconductor. The story can be read here. Read the article for further links that include an audio interview."

7 of 102 comments (clear)

  1. The link is incorrect... by snookums · · Score: 5, Informative


    Try this one (http://www.eet.com/story/OEG20010924S0101)

    Blah, blah. Lameness filter doesn't like short posts so I'll put a little padding here. Sorry to ramble, but you know how it is...

    --
    Be careful. People in masks cannot be trusted.
  2. Links by tomknight · · Score: 4, Informative
    Well here's another karma-whoring link for y'all - it's the news article from Purdue University

    http://news.uns.purdue.edu/UNS/html4ever/010917.Ch ang.quantum.html

    Tom.

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    Oh arse
  3. Printable version (was Re:The link is incorrect..) by Anonymous Coward · · Score: 1, Informative

    At http://www.eet.com/printableArticle?doc_id=OEG2001 0924S0101

  4. Key distribution solved by Quantum, not hurt. by Jayson · · Score: 2, Informative
    Nobody yet managed to transfer information like this, since first seperating them is difficult, and second the key to do something against the second one that would change the other one.
    From what I know, IBM Watson has done a quantum key distribution system, only over 30cm and a slow 10bit/s, though.
    Beside the physical part, there is another criptrograic prolbem: transportation of the key. You've to transport -securly- the key to other side, without having it replaced. So also this hypothetical communication is only as sure as your key-transportation is
    Yes, true. But one nice thing that quantum gives us is (probabilisticly) secure key distribution. The short is that you can exchange photon pairs with the person to comminucate to. You determine a polarization randomly before sent. They record what they get, then publicly anounce the type of polarization: 2 types with 2 directions, and you can only determine type of direction (Heisenburg tells us this). You tell them which ones are correct. Then direction becomes the 1's and 0's of the key. An eavesdropper by measuring the photon will introduce a 25% error since they/you can only determine either direction or type and they will get the other wrong half of the time. Also, the eavesdropper would need to detect the photon, then retransmit another, but this will destroy the quantum correlation betweent the two entangled photons so you will also know that way.

    Somebody please correct the problems here. I don't really know what I am saying and am bound to be wrong in places.

    -j
  5. Re:Obsoletes planned crypto laws by Omnifarious · · Score: 4, Informative

    Two misconceptions here:

    First, symmetric key encryption is still pretty good in the face of quantum computing. It isn't as good as it was. I think the difficulty factor goes down to the square root of the original difficulty factor. For a 256 bit key, that's sitll 2^128 operations to brute force it. That's pretty secure.

    Second, quantum cryptography doesn't work the way you describe.

    Quantum cryptography works by generating a truly random keystream using entangled particles. Since the particles are entangled, both people can get their own particle and know the state of the other person's particle. They can't alter the state of the other person's particle in any way, but they do know it.

    This allows one-time pads to be securely exchanged over a distance. If someone listens in to the entangled particle stream, this irrevocably alters it, and when both sides compare a few (not all) of their shared random bits over an insecure channel, they can detect this snooping.

    Quantum cryptography does NOT, I repeat, DOES NOT allow you to communicate with no latency. The speed of light applies to the particles in the entangled stream, and it applies to subsequent communications encrypted using the information in these particles. One particle of an entangled pair can only detect the collapse of the quantum wave function (i.e. when the particle is 'read') for the other particle. No other state changes can be detected by the other particle. No faster than light information exchange to see here people, move along.

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    Need a Python, C++, Unix, Linux develop
  6. ResearchIndex cites and clarification by Jayson · · Score: 3, Informative

    ResearchIndex should be in everybody's bookmarks.

    In the previous post, I wasn't quite clear (shoot me, it's 5am and I've been up all night): there are a couple of different methods that I was pulling information from. In the penultimate paragraph, the final sentence was an aside referring to a method of using entanglement to transfer the keys. The rest of the post was referring to a method using polarisations and Heisenburg. Here are the two links to the papers.

    First, for the transfer by polarisations. If you are at Cal, then go ask Vazirani, it looks like he has coauthored with them: http://citeseer.nj.nec.com/bennett92experimental.h tml

    Then on the use of entanglement (they do not have the actual paper, bastards): http://citeseer.nj.nec.com/context/18763/0

    -j

  7. Re:Obsoletes planned crypto laws by Dooferlad · · Score: 4, Informative
    That's presuming you have a known plaintext. That's usually not too hard to engineer, but with careful implementation, it should actually be very hard.


    I agree, but there is always a chance. Of course you could enter quantum plaintext which is trial encrypted by a quantum key and then retrieve it that way :)

    Some useful background on Quantum Entanglement and Quantum Communication can be found at the Centre For Quantum Communications for confused readers (like me).

    -- Dooferlad