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    Finally, Schrodinger's Cat Hits A Nobel!
    By Johannes Koelman | October 9th 2012 01:29 PM | 4 comments | Print | E-mail | Track Comments
    About Johannes

    I am a Dutchman, currently living in India. Following a PhD in theoretical physics (spin-polarized quantum systems*) I entered a Global Fortune

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    Well, kind of. David Wineland and Serge Haroche have not endangered any living beings. That is to say: probably not in their physics experiments. 

    Yet, although they stayed at a safe distance from bringing life form into quantum superposition, both physicists have thoroughly explored the schizophrenic world of the quantum, and opened the door to the direct observation and manipulation of quantum superpositions. By cleverly exploiting the fundamental interaction between light and matter, the two quantum optics experts have managed to pull off a range of experiments in which Schrödinger's cat states lead to bizarre results.



    Quite aptly, where quantum physics blurs the distinction between the wavy nature of light and the particle nature of matter, Wineland prefers to manipulate matter with light, while Haroche manipulates light with matter. According to what is arguably the deepest truth in quantum mechanics, either approach provides a valid methodology to explore the quantum. 

    Rather than me attempting to give a flavor of the amazing experiments carried out by the Boulder, Colorado (Wineland) and Paris (Haroche) groups, I better give the word to one of the two laureates(If you permit yourself no more than a single mouse click on this page, make sure it is a click on the previous link...)

    In the popular media you will read a lot about quantum superposition experiments enabling amazing quantum computing opportunities. Dramatic claims about prime factorization are being made. Soon your credit card transactions are prone to quantum hacking! Take these claims with a sizable grain of salt. The current state-of-the-art in quantum computing has allowed us to establish that 21 is probably equal to 3 times 7. And that was a tour de force. 

    But that takes absolutely nothing away from the landmark achievements obtained by Wineland and Haroche. The guys in Stockholm have again done a great job. Congratulations to David Wineland and Serge Haroche, and their many collaborators!


    PS. Alfred Kastler, Alain Aspect, Claude Cohen-Tannoudji, Serge Haroche. What is it that pulls the French into the quantum world of light and atoms? Louis de Broglie's legacy perhaps?

    Comments

    Just a little question about quantum computing. I may be the only person on the planet who doesn't know the answer or maybe nobody knows but everyone brushes the question under the carpet... So I'm just asking.

    You say:
    In the popular media you will read a lot about quantum superposition experiments enabling amazing quantum computing opportunities. Dramatic claims about prime factorization are being made. Soon your credit card transactions are prone to quantum hacking! Take these claims with a sizable grain of salt. The current state-of-the-art in quantum computing has allowed us to establish that 21 is probably equal to 3 times 7. And that was a tour de force.
    Setting up and using a computing system requires a certain amount of effort - you need to set up the data "registers" for instance and that involves degrading your own system as you exchange the random data there for your own data, q-bit by q-bit. What I'd like to know is whether, at this fundamental level, quantum computing costs less than the classic kind? 

    A *graded* slit diffracts according to the Fourier transform of its spatial density profile. In the good old days you could correct for fuzziness in photographs this way with little effort. You could certainly argue that there's a hell of a lot of processing going on - comparable to Photoshop - in that superposition. Perhaps if you want a simple answer to a difficult problem the gains are potentially enormous but if you want to extract a vast amount of processed data they are not? But that's just me having a wild guess at my own question.

    Johannes Koelman
    What I'd like to know is whether, at this fundamental level, quantum computing costs less than the classic kind? 
    Let me start by stating that I am by no means an expert on quantum computing. Yet, I think I can state with some confidence that - in theory at least - quantum computing can outperform classical computing by any factor. Take prime factorization as an example. Factoring an N-digit number on a classical computer requires an effort exponential in N. A quantum computer running Shor's algorithm, however, would perform the same task with an effort polynomial in N. 




    Nice article. Good to see you back, Mr Cowell.

    Johannes Koelman
    Ha, ha, you are not the first one making that comparison here. But in real life I never get that remark!