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Making Cesium Atoms Do a Quantum Walk

Posted by kdawson on from the like-a-perp-walk-only-without-the-cameras dept.

An anonymous reader recommends an Ars Technica account of a breakthrough in efforts toward quantum computing. German scientists have managed to get cesium atoms in a state called a "quantum walk": basically a superposition of all the possible states of a particle. "Quantum walks were first proposed by physicist Richard Feynman and are, in terms of probability, the opposite of a random walk. A random walk might be modeled by a person flipping a coin, and for each flip he steps left for heads and right for tails. In this case, his most probable location is the center, with the probability distribution tapering off in either direction. A quantum walk involves the use of internal states and superpositions, and results in the hypothetical person 'exploring' every possible position simultaneously." In the abstract of the paper from Science (subscription needed for full-text access), the researchers say: "Our system allows the observation of the quantum-to-classical transition and paves the way for applications, such as quantum cellular automata."

9 of 117 comments (clear)

  1. I'm not drunk, offischer. I'm doing a quantum walk by wdef · · Score: 5, Funny

    "And that geodesic is not shtraight either. Sho's I'll just superimpose my states back in da car and be on my way ..."

  2. Reliability of Cesium by BadAnalogyGuy · · Score: 4, Interesting

    Cesium is an interesting element in that it is perfectly reliable. While some elements will differ in atomic weight due to random changes in their electron sphere radii and the number of neutrons in the nucleus, Cesium has a perfect vibration rate independent of external stimuli. It is so regular and reliable, in fact, that we base our entire measurement of time on clocks composed purely of Cesium.

    If, as is demonstrated here, Cesium can be used to explore multiple quantum states in a regular and reliable fashion, the possibility to build quantum computers and automata based on Cesium goes way up. Not only would these "computers" function better than our current computers, they would always be 100% perfect (unless Intel manufactures them, lol) and not prone to error or breakage.

  3. Quantum CPU extensions? by DigiShaman · · Score: 3, Interesting

    As far as I know it, we have three main instruction sets. Integer, Floating Point, and Vector (SSE, MMX..etc). Would it more likely be that we would end up with the forth set being Quantum? Or, would it be possible to have an entire CPU quantum based?

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    1. Re:Quantum CPU extensions? by BadAnalogyGuy · · Score: 5, Funny

      To your first question: Yes. There would be a new instruction set called "Eigen". It would contain all possible values simultaneously. The interesting thing about such a value is that it could be used to determine the correct value of any problem simply by casting it to the appropriate data type. Since the other instruction sets can only contain a single value at any time, the correct value (for our universe) is automatically saved in the other data type.

      For your other question: Yes and no.

  4. Re:Encryption plan by Anonymous Coward · · Score: 4, Funny

    Do we have a plan for when one day, our current methods of encryption all become breakable at once?

    What a wasted opportunity, your first post is supposed to say "First post, or is it?"; well I suppose you can always wait for the next quantum computing breakthrough.

    "3very p0st" would have been an acceptable alternative, in my opinion.

  5. Re:Encryption plan by fuzzyfuzzyfungus · · Score: 4, Funny

    A massive cash advance drawn against every credit card in the world, and a castle made of pure unicorns in a country with flimsy extradition treaties?

    That's my plan, anyway.

  6. Misunderstanding this, most likely by gcnaddict · · Score: 3, Interesting

    Theoretically speaking, if we could get, say, an entire ship and all of its inhabitants to do this "quantum walk"...

    wouldn't we be well on our way towards creating an improbability drive?


    I'm probably hugely stretching this beyond what it means.

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    1. Re:Misunderstanding this, most likely by shermo · · Score: 4, Informative

      Quantum mechanics applies to large particles. Classical mechanics are merely an approximation of quantum mechanics when applied to large particles.

      Wikipedia to the rescue

      http://en.wikipedia.org/wiki/Correspondence_principle

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    2. Re:Misunderstanding this, most likely by Anpheus · · Score: 3, Insightful

      From what I've read on the issue, such as Feynman's books and other novels targeted toward those of us who do not have a complete grasp of quantum mechanics, you are wrong.

      Caveat emptor, this is merely what I've read:

      Classical mechanics as explained by Feynman were the result of the sum of all possible histories, among other interpretations. Regardless of one's interpretation, Feynman and others found that as you crunch the math for larger and larger quantities of particles, the results closer and closer approximate what we think of as classical physics. As a result, classical physics is an approximation of quantum mechanics, which is a theory of how the universe really works.