Workshop about Q in school

I am attending a very interesting workshop with many secondary school teachers of Switzerland. It’s in French, but I blog on it in English. Today, two notes:

Note 1

Jean-Marc Levy-Leblond has presented a nice conceptual framework to understand how the notion of “wave-particle duality” arose. He pointed out that the classical notion of “particle” is discontinuous (or discrete) both in its spatial extension and in its quantity; the classical notion of field is “continuous” in both. The “quantons” (he likes this term, and it’s practical indeed) are continuous in spatial extension but discrete in quantity.

A nice hint… but no need to expand: he immediately said that, nowadays, the notion of “wave-particle duality” should just be erased forever from our vocabulary — on which, I cannot agree more.

Note 2

This is just devoted to state my admiration for the teachers I talked to (to be extended by extrapolation to all the participants). With some, I even ended up talking already of the latest results of axiomatics, of device-independent, of indeterminism… I’ll blog about these ideas one day. Now it’s dinner time.

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About valerio

Principal investigator at Centre for Quantum Technologies and professor at National University of Singapore

Posted on September 22, 2011, in Common knowledge, Philosophy. Bookmark the permalink. 3 Comments.

  1. I agree with Valerio about our course “Q in the school”. I hope that all the participants could feel the beautifulness of quantum physics that taught directly from some of the most influent researcher of the field.

  2. Hello, I just stumbled upon your blog and found it to be a great read (well… I am also Shiyang and Lynn’s junior)!
    I am just beginning to be interested in the quantum world and want to find out as much about it as possible. May I know why you think that the notion of ‘wave-particle duality’ should be done away with?

    • There are many reasons to abandon the notion of “wave-particle duality”:
      (1) The speaker I was mentioning in my post was arguing from a philosophical standpoint, basically saying that if something is new, it is better to give it a new name, rather than mixing up existing notions.
      (2) The operational people will tell you that this notion does not play any role in the formalism: when we compute with quantum theory, the procedure is unique and well-defined, one does not have to think “should I use a particle description or a wave description here?”
      (3) I find another reason more appealing, because more related to physics: wave-particle duality provides a nice mental picture of single-particle interferences. But it fails to describe entanglement in a satisfactory way! You can of course force your mind into imagining a “wave-particles” formalism that describes entanglement; but the wave must change instantaneously all over the universe when a measurement is made in a given location. This removes all the intuitive appeal of the picture.

      Now, you may still find the wording “wave-particle duality” in some serious articles; for instance, my colleague Berge Englert has several works on it. But there, it is meant as a technical and quantitative notion: the more one knows about “which path” (“particle”), the less visible the interference fringes will be (“wave”). This is very far from a cheap and wrong metaphysics in which quantum objects would be “waves and particles”.

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