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Wanted: quotes that encourage thinking of experiments instead of measurements

  1. Jun 23, 2009 #1
    The classic reference on this is Bell's (highly recommended) polemic "Against measurement", which is in the 2nd edition of Speakable and unspeakable in quantum mechanics (but not in the 1st edition; it can also be can be found in the original, Physics World 3 (August 1990), page 33).
    A quote to much the same effect can be found in Feynman & Hibbs, "Quantum Mechanics and Path Integrals" (McGraw-Hill, New York, 1965), pages 22-23, where we find
    “The usual separation of observer and observed which is now needed in analyzing measurements in quantum mechanics should not really be necessary, or at least should be even more thoroughly analyzed. What seems to be needed is the statistical mechanics of amplifying apparatus”.​
    I would be grateful for any quotes that people here on Physics Forums think might be to the same effect, emphasizing description of an experiment, and particularly the thermodynamics or statistical mechanics of experimental apparatus, in preference to the more conventional descriptions of measurement and of systems that are measured.
  2. jcsd
  3. Jun 24, 2009 #2
    I guess I'll add this quote, found today in re-reading Klaas Landsman's enlightening article, "When champions meet: Rethinking the Bohr–Einstein debate", Studies in History and Philosophy of Modern Physics 37 (2006) 212–242 (preprint http://arxiv.org/abs/quant-ph/0507220" [Broken]):
    "However far the phenomena transcend the scope of classical physical explanation, the account of all evidence must be expressed in classical terms. The argument is simply that by the word experiment we refer to a situation where we can tell others what we have done and what we have learned and that, therefore, the account of the experimental arrangements and of the results of the observations must be expressed in unambiguous language with suitable application of the terminology of classical physics" (Bohr, 1949, p. 209, Discussion with Einstein on epistemological problems in atomic physics. Albert Einstein: Philosopher-Scientist, pp. 201–241. Schilpp, P.A. (Ed.). La Salle: Open Court.).​
    The role of this classical description of an experiment in the Copenhagen interpretation in modeling the experiment using the Hilbert space mathematics of quantum theory has never been entirely clear to me, however. I've always wondered how detailed the classical description of the experimental apparatus should be? Should it be accurate at the atomic scale when it's necessary to describe precisely what exotic materials should be used in a measurement device, and the voltages that should be applied, or should we give an instrumental description of how to manufacture the exotic material needed? Where is quantum theory in such descriptions?
    Last edited by a moderator: May 4, 2017
  4. Jun 24, 2009 #3
    The following is not quite a "quote" (I am not going to look for a specific quote right now), but a citation: arXiv:quant-ph/0702135 (Phys. Rev. A 64, 032108 (2001), Europhys. Lett. 61, 452 (2003), Physica E 29, 261 (2005)). Take it for what it's worth. It was eye-opening for me though.
  5. Jun 24, 2009 #4
    Thanks, Akhmateli. Perhaps actual quotes was a lot of heavy lifting to ask for here! Anyway, the Physica E paper looks good to cite for my purposes. It looks like a passable attempt to do as requested by Feynman & Hibbs, and its introduction expresses sentiments reasonably in line with my own.
  6. Jun 24, 2009 #5
    You are welcome
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