back to article Quantum computing gets recursive

When a quantum computer can produce results that would take thousands of years to produce out of a classical computer, an obvious question arises: if you've given the wrong answer, how would you know? That's a question to which University of Vienna boffins have turned their attention to. A computation involving a handful of …

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  1. Martin Budden Silver badge
    1. Martin Huizing

      Come on!

      First comment has not one reference to THGTTG?

      One quantum computer where we can not verify the answer, so we breathe life in another which helps with asking the right question.

      1. Martin Budden Silver badge

        OK, OK, OK!!!

        42.

        Happy now?

  2. Martin Huizing
    Thumb Up

    On the other hand...

    The moment we actually create a working quantum computer, the whole game chances and there will be a leap forward , technology wise, similar to the industrial revolution.

    3d printers will be the norm as they will be able to reproduce every carbon made item on the menu.

    3d printed computers with unfathomable capabilities, able to perform tasks in seconds that would take current cluster computers months to compute. Eye wear that can visualize any environment and setting any where in the world and meet your virtual friends there.

    The future is bright, the future is quantum!

  3. John Smith 19 Gold badge
    Unhappy

    So something you can actually *program* still as far away as ever.

    <sigh>.

    If you're worried about the results how do know that multiple wrong answers don't converge onto the right answer for the trap question before haring off into different directions of wrongness. I'm thinking of the stability diagrams used in control systems engineering, where something looks stable but has hidden features in it's behavior that make it wildly unstable with slightly different inputs.

  4. Paul Crawford Silver badge

    That meant nothing to me, University of Vienna...

  5. Chuunen Baka

    Useful?

    Are these hypothetical devices only useful for number crunching? Most computing is actually data storage, retrieval, filtering and transforming. The clever stuff is still in the design of algorithms to acheive new things with the data. Obviously you can run an algorithm more times but the time-consuming part is usually all in the i/o. I don't see how quanta help with that.

    1. DanDanDan

      Re: Useful?

      Two words: Grover's algorithm

      1. Chuunen Baka

        Re: Useful?

        "Two words: Grover's algorithm"

        Wikipedia: "When applications of Grover's algorithm are considered, it should be emphasized that the database is not represented explicitly. Instead, an oracle is invoked to evaluate an item by its index. Reading a full data-base item by item and converting it into such a representation may take a lot longer than Grover's search. "

        So it's still all to do with i/o unless someones working on a quantum database. Hey, your data's probably in here somewhere.

  6. DanDanDan

    assert()

    Is this just the quantum mechanical equivalent of an assert() function or have I missed something?

  7. Annihilator
    Paris Hilton

    Ponderings

    The mistake everyone makes at some point when tinkering with recursive functions, is messing up the break point and ending up with a stack overflow, or falling into an infinite loop.

    If a quantum computer calculates all states at once, how does it cope if the number of states is infinte?...

  8. Smokingman

    Recursion

    The biggest problem with recursion is the biggest problem with recursion......

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