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.


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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