Why do almost all books on quantum start out with the double slit experiment and show how a single particle interferes with itself and say its a wave and particle when Yves Couder has shown on a macroscopic level that the phenomenon can be explained with pilot waves?

I am very disappointed that videos and all these books took something that de Broglie and Bohm could explain and turned the double slit experiment into something spooky.

Is there something better to explain duality if it exists ?


closed as off-topic by ACuriousMind, CuriousOne, user36790, John Rennie, Kyle Kanos Nov 1 '15 at 11:32

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    $\begingroup$ Can you provide a link to whatever Yves Couder is saying? Otherwise, the question is hard to answer. $\endgroup$ – garyp Oct 31 '15 at 18:31
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    $\begingroup$ I'm voting to close this question as off-topic because it is a rant about physics pedagogy, not a question about physics. $\endgroup$ – ACuriousMind Oct 31 '15 at 20:14
  • $\begingroup$ Almost all books that do that are making a grave pedagogical mistake because they teach students a completely false idea about quantum mechanics. But then, so would books that would teach pilot waves, which are neither required nor useful for understanding QM... they are merely another flavor of the day of poor reasoning about otherwise simple phenomena. $\endgroup$ – CuriousOne Oct 31 '15 at 20:18
  • $\begingroup$ QM is now over a century old. there is a vaguely similar concept in software dev called "lock in" that also explains inertia and resistance in consideration of "alternative theories". more on the wave experiments here, superclassical/ emergent QM, recent developments, rough outline/ overview/ leads $\endgroup$ – vzn Nov 2 '15 at 23:46

Indeed, it could be helpful conceptually if textbooks also mention the pilot wave theory of de Broglie and Bohm, which provides an example of how particles being guided by interfering waves can lead to interference patterns in the statistical distribution of particle positions. The experiments by Couder on droplets "walking" on water, which you mention, illustrate such a behaviour in a different physical context (here's a video on those experiments), though they are not described by the same equations and have nothing directly to do with quantum mechanics.

However, here are a few reasons why textbook authors might hesitate to bring up the pilot wave theory early on in the book:

  • It is only one of many possible interpretations of quantum mechanics, and bringing it up early on in the book might then leave students confused (believing that the pilot wave interpretation is an integral part of QM)

  • The trajectories themselves remain unobservable, so there are no predictions that are specific to the pilot wave theory which could be experimentally tested

  • The description of many-particle systems requires trajectories that are guided by the rather abstract many-particle wavefunction (that depends on all particle-positions simultaneously), thereby making the theory nonlocal (as any hidden variable theory that correctly reproduces QM has to be, according to Bell's theorem)

  • Up to now there seems to be no convincing relativistic extension (people are working on this)

  • For me, one of the most striking problems of the pilot-wave theory is that it is unable to give the correct QM predictions if one allows for measurements on far-away particles to take place not simultaneously but at arbitrarily chosen slightly different times (in a relativistic setting, this would come about simply by doing simultaneous measurements in an arbitrarily chosen Lorentz frame). This is analyzed carefully in the article by Berndl, Duerr, Goldstein and Zhangi: http://arxiv.org/abs/quant-ph/9510027 In fact, it even applies to any trajectory-based hidden variable theory, not only the particular model advanced by de Broglie and Bohm.

  • $\begingroup$ Thank You. Saying that the interference pattern could only be caused in one way and then to see it demonstrated in macro means the first chapter of most books I have is worthless. $\endgroup$ – JohnnyM Oct 31 '15 at 22:35
  • $\begingroup$ Well, I think you are too harsh: maybe they are too rash in emphasizing the mystery of the double slit, but I am sure the first chapter contains many other useful pieces of information. $\endgroup$ – Florian Marquardt Nov 1 '15 at 9:15

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