Nobel Laureates on the QM Interpretation Mess

Update:  Perusing the web I noticed that John Preskill [not yet a Nobel laureate 🙂 ] also blogged on the same survey.  Certainly another prominent voice to add to the mix.


In the LinkedIn discussion to my earlier blog post that was lamenting the disparate landscape of QM interpretation, I had Nobel laureate Gerard ‘t Hooft weighing in:

Don’t worry, there’s nothing rotten. The point is that we all agree about how to calculate something in qm. The interpretation question is something like: what language should one use to express what it is that is going on? The answer to the question has no effect on the calculations you would do with qm, and thus no effect on our predictions what the outcome of an experiment should be. The only thing is that the language might become important when we try to answer some of the questions that are still wide open: how do we quantize gravity? And: where does the Cosmological Constant come from? And a few more. It is conceivable that the answer(s) here might be easy to phrase in one language but difficult in another. Since no-one has answered these difficult questions, the issue about the proper language is still open.

His name certainly seemed familiar, yet due to some very long hours I am currently working, it was not until now that I realized that it was that ‘t Hooft.  So I answered with this, in hindsight, slightly cocky response:

Beg to differ, the interpretations are not more language, but try to answer what constitutes the measurement process. Or, with apologies to Ken, what “collapses the wave function”: The latter is obviously a physical process. There has been some yeoman’s work to better understand decoherence, but ultimately what I want to highlight is that this sate of affairs, of competing QM interpretation should be considered unsatisfactory. IMHO there should be an emphasis on trying to find ways to decide experimentally between them.

My point is we need another John Bell.  And I am happy to see papers like this that may allow us to rule out some many world interpretations that rely on classical probabilities.

So why does this matter?  It is one thing to argue that there can be only one correct QM interpretation, and that it is important to identify that one in order to be able to develop a better intuition for the quantum realities (if such a thing is possible at all).

But I think there are wider implications, and so I want to quote yet another Nobel laureate, Julian Schwinger, to give testament to how this haunted us when the effective theory of quantum electrodynamics was first developed (preface selected papers on QED 1956):

Thus also the starting point of the theory is the independent assignment of properties to the two fields, they can never be disengaged to give those properties immediate observational significance. It seems that we have reached the limits of the quantum theory of measurement, which asserts the possibility of instantaneous observations, without reference to specific agencies.  The localization of charge with indefinite precision requires for its realization a coupling with the electromagnetic field that can attain arbitrarily large magnitudes. The resulting appearance of divergences, and contradictions, serves to deny the basic measurement hypothesis.

John Bell never got one of these, because of his untimely death.

6 thoughts on “Nobel Laureates on the QM Interpretation Mess

  1. Fret not, and take a bit of heart from the case of the late great (later to win the Nobel Physics Prize in the case of) Dr. Donald Glaser
    ( ) It was written in the Times that:

    “Dr. Glaser, who was teaching at the University of Michigan at the time, was fortunate that he did not know that Fermi had calculated that a bubble chamber would never work. Only afterward, after Fermi had invited Dr. Glaser to the University of Chicago to give a talk about the bubble chamber, did Dr. Glaser look up Fermi’s calculation in a thermodynamics textbook. There he found an erroneous equation.

    “It’s just a small error, but that error made it possible for him to prove that it couldn’t work,” Dr. Glaser said of the bubble chamber in an oral history conducted by the Bancroft Library at Berkeley. “And luckily I didn’t know about his book because it would have turned me off. Instead, I did my own calculation, and it was hard, but that was the critical difference.”

    After winning the Nobel, Dr. Glaser, frustrated that particle physics was adopting huge atom smashers requiring large teams of scientists, switched to molecular biology and studied bacteria and viruses. ”

    Now (in my wild dreams and opinion) the two branches of science Dr. Glaser worked in are coming together to settle some important questions about ‘square one’ and how matter and anti matter are made and move by means of bacteria and the virus as a power plant of the breeder reactor that runs the power plant that answers the question posed by Gerard ‘t Hooft to your thread question in general was a reply of a few was this; “where does the Cosmological Constant come from?”

    My humble answer (per the Cosmological Principle) the atomic power contained int the nuclear core of Carbon, Nitrogen, Oxygen, making and breaking the Hydrogen bond thus in the quantum dynamic of making and repairing three generations of quarks ‘fused’ by neutrinos which therefore form the radioactive ‘foam of space’ as so much atmosphere around which ‘rotary evaporator’ condenser/Higg’s mechanism which makes matter happen like fresh racks of balls and then vanish like so many billiard balls sunk as progress scored on Gods elementary table in the Pool Hall of the evolving Universe so speaking/writing utterly metaphorically* while powered by the energy mass equivalence of the Sun, moon, and Stars – that I seek to know, a bit better: so as to know my self and ‘space in time’ by attempting to know the structure and essence of Earth, wind, and fire, by reading and heading what the ‘old school’ has to say on the subject so as to have a point of view as old, and new as ‘the books’, being rewritten daily, by inquiring minds in search of answers the best way to find them, which is by taking y0ur thoughts and ‘bouncing them off the wall’ to see who takes a look/whack at your material/data stack.

    You just never know; everything.

    Thanks for broaching the topic.

    For if knowledge is power, and E=MC2, the perhaps it stands to reason that, ‘knowledge shared, is knowledge squared.


    *and as a Political Scientist who studies, thinks and writes about Theoretical Physics out of personal interest in the subject. I confess to doing so without formal training, therefore my life experience, reading and research are correspondingly compensatory to have a semi-clue of what I speak – which I presume to, or I surely would not be writing what I believe to be true from my and the ‘safety committee’s research pioneering research and life experience with ‘bubble chamber’ technology – which btw is still reported to be ‘the key’ and or ‘ticket’ there are many options and variations on the form factor – if you must know, and you should.

  2. Penrose and ‘t Hooft have come around to Einstein’s POV concerning the interpretation of quantum theory, as we learn in Kumar’s recent ‘Quantum.’

    “A theory that yields “maybe” as an answer should be recognized as an inaccurate theory.”

    ~’t Hooft

    “Can it really be true that Einstein, in any significant sense, was a profoundly “wrong” as the followers of Bohr maintain? I do not believe so. I would, myself, side strongly with Einstein in his belief in a submiscroscopic reality, and with his conviction that present-day quantum mechanics is fundamentally incomplete.”


    KUmar |

    Dirac also came around, as we learn in a recently republished article in SciAm.

    “If h-bar is a derived quantity instead of a fundamental one, our whole set of ideas about uncertainty will be altered: h-bar is the fundamental quantity that occurs in the Heisenberg uncertainty relation connecting the amount of uncertainty in a position and in a momentum. This uncertainty relation cannot play a fundamental role in a theory in which h-bar itself is not a fundamental quantity. I think one can make a safe guess that uncertainty relations in their present form will not survive in the physics of the future.”

    ~Dirac |

    He makes the point explicitly in the biography by Pais:

    “It seems clear that the present quantum mechanics is not in its final form […] I think it very likely, or at any rate quite possible, that in the long run Einstein will turn out to be correct.”

    ~Dirac |

    Born gave us the statistical interpretation of the wave function. Less familiar is what he said at the time.

    “Anyone dissatisfied with these ideas may feel free to assume that there are additional parameters not yet introduced into the theory which determine the individual event.”

    ~Born |

    We often read that quantum theory covers all known phennomena. I their admirable text on the “mathematics of Classical and Quantum Physics,’ Byron and Frederick write:

    “Axiom I. Any physical system is completely described by a normalized vector (the state vector or wave function) in Hilbert space. All possible information about the system can be derived from this state vector by rules (…)”

    Yet the author of the wave function would seem to have disagreed:

    “If you ask a physicist what is his idea of yellow light, he will tell you that it is transversal electromagnetic waves of wavelength in the neighborhood of 590 millimicrons. If you ask him: But where does yellow comes in? he will say: In my picture not at all, but these kinds of vibrations, when they hit the retina of a healthy eye, give the person whose eye it is the sensation of yellow.”

    ~Schrödinger |

    The difficulty cited by Schrödinger has historically been dodged in one of two ways: (1) We have either swept color into the dustbin of the mind; or (2) identified it with the wavelength of the associated light.

    Mach addressed the first option in his book on ‘The Analysis of Sensations.’

    “A color is a physical object as soon as we consider its dependence, for instance, upon its luminous source, upon temperatures, upon spaces, and so forth.”

    ~Mach |

    The second option is merely a matter of widespread ignorance, propped up by shoddy scholarship. Grassmann, Maxwell, Schrödinger, Weyl and Feynman all tell us quite explicitly that color behaves like a vector — a fact borne out by the technology behind our color TVs and computer monitors.

    Whereas a wavelength (or frequency) is a scalar, being a simple magnitude.

    Why is this important? For starters, colors manifest rather obvious symmetries — the kinds of symmetries which make vectors helpful in physics.

    And then, the dual of a vector is a differential form, which has the dimensions of area. And what we observe are colored areas.

    When light Dopplers, its wavelength and frequency change, and so does its energy, by E = hv.

    Changing the energy of a photon rotates its vector in Hilbert space. The new vector has a new color associated with it, and so it would seem that we have rotated the color vector via the same operation.

    Since energy is conserved, the associated wavelength of constant energy will also remain invariant, leaving us with a vector pointing to the same place in Hilbert space, as well as color space.

    Helmholtz observed that “Similar light produces, under like conditions, a like sensation of color.” Color is, of course, one of Locke’s “secondary qualities.” Generalizing with a view to Heisenberg’s formulation of quantum mechanics, we can say that:

    The same state vector, acted upon by the same operators A, B, C … produces the same spectrum of secondary qualities.

    Where does this get us? Rather far, perhaps, for as the mathematician Steen reminds us, early on in the history of quantum theory, “The mathematical machinery of quantum mechanics became that of spectral analysis… ”


    Finally, Weyl tells us that “the colors with their various qualities and intensities fulfill the axioms of vector geometry if addition is interpreted as mixing; consequently, projective geometry applies to the color qualities.”

    Considering that the dualities which crop up in contemporary physics had their provenance in projective geometry, this point should be of general interest.

    Mapping the projective plane to a color sphere by way of a double cover gives us a complex, projective vector space, where the antipodes are naturally interpreted as the same color x, rotated thru 180 degrees to give us the same color, but wholly out of phase. Adding x to its opposite (-x) gives us “no light” or darkness, thus giving us a group structure, the other axioms being satisfied in an obvious way.

    Again, one doesn’t have to go far to bump into complex, projective vector spaces these days. The interested reader is encouraged to google that term, together with “gauge” and/or “M-theory.”

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