“It Ain’t Necessarily So” Interpretations and Misinterpretations of Quantum Theory John Stachel

1. “It Ain’t Necessarily So”Interpretations and Misinterpretations of Quantum TheoryJohn Stachel Frontiers of Fundamental Physics 14 Faculty of Sciences (AMU) Marseille, 15-18 July 2014

3. It Ain't Necessarily So  by George Gershwin It ain't necessarily so It ain't necessarily so The t'ingsdatyo' li'ble To read in de Bible, It ain't necessarily so. …………………………… I'm preachin' dis sermon to show, It ain'tnece-ain'tneceAin'tnece-ain'tneceAin'tnecessarily ... so ! 

4. My Apologies in Advance Time limits require brevity and brevity is the mother of dogmatism. None of my statements should be interpreted dogmatically– they are all meant to stimulate critical thinking and further discussion. For a copy of my PowerPoint just email john.stachel@gmail.com

5. Examples of Misinterpretationsfrom Two Widely Praised 2013 Books • What is the Copenhagen interpretation? • AreDuality and Complementarity the same?

6. Princeton University Press, 2013

7. Einstein and the Quantum Stone attacks “theCopenhagen interpretation,” focusing on “Born’s probabilistic interpretation of the wave-function, Heisenberg’s uncertainty principle and Bohr’s mysterious complementarity principle.” (p. 281)

8. Einstein and the Quantum “Einstein’s later critiques of quantum theory focused less on its indeterminacy and more on its strange epistemological status. In quantum mechanics the actual act of measurement is part of the theory; these magic coins just mentioned exist in a state of (heads, tails)-(tails, heads) uncertainty until they are measured, and then they are forced to ‘decide’ which state they are in.”

9. Heisenberg’sCopenhagen Interpretation Stone does not seem to be aware that he is giving Heisenberg’s interpretation of quantum mechanics, which is quite different from Bohr’s interpretation. You don’t have to take my word for this:

10. “Nine formulations of quantum mechanics,” Daniel F. Styer et al, Am. J. Phys. 70 (2002): pp. 288-297 [O]f the two primary architects of the Copenhagen interpretation, Werner Heisenberg maintained that ‘observation of the position will alter the momentum by an unknown and undeterminable amount,’ whereas Niels Bohr ‘warned specifically against phrases, often found in the physical literature, such as ‘disturbing of phenomena by observation.’

11. “Nine formulations of quantum mechanics,” Daniel F. Styer et al, Am. J. Phys. 70 (2002): pp. 288-297 The wave function should be regarded as a mathematical tool for calculating the outcomes of observations, not as a physically present entity existing in space such a football, or a nitrogen molecule, or even an electric field.

12. Examples of Misinterpretations from Two Widely Praised 2013 Books • What is the Copenhagen interpretation? • Are Duality and Complementarity the same?

13. Pegasus Books, 2013

14. Farewell to Reality Danish physicist Niels Bohr and German Werner Heisenberg argued that particles and waves are merely the shadowy projections of an unfathomable reality into our empirical world of measurement and perception. …. This approach to quantum theory became known as the Copenhagen interpretation….At the heart of this interpretation lies Bohr’s notion of complementarity, a fundamental dualityofwave and particle behavior.

15. But According to Bohr They Are Not Since Bohr introduced and developed the concept of complementarity in quantum mechanics, on this one I’ll let Bohr speak for himself:

16. Niels Bohr 1885-1962

17. The Causality Problem in Atomic Physics (1938) It is true that the duality between the undulatory and corpuscular conceptions exists for matter as well as for light, but this is only one aspect of a symbolical formalism and its interpretation must be found in the classical conceptions. Just as the mass and charge of the electron can only be defined classically, the description of the pheno-mena of radiation cannot dispense with the idea of the electromagnetic wave field.

18. The Causality Problem in Atomic Physics (1938) The concepts of the photon and the material wave are on the contrary purely abstract methods of considering the general nature of complementarity that exists, by reason of the individuality of the quantum of action, between the spatio-temporal representation and the principle of conservation of momentum and energy.

19. DUALITY CLASSICAL (h=0) Radiation Matter Waves Particles MATHEMATICAL REPRESENTATION Characteristics Trajectories (wave fronts) (world lines, characteristic strips) DUALS Bicharacteristics Ensemble of trajectories (rays) (characteristic function) QUANTUM MECHANICAL (h>0) photon wave function

20. COMPLEMENTARITY SPACE-TIME DESCRIPTION CONSERVATION OF (x,t) ENERGY- MOMENTUM (E, p) CLASSICAL (h=0) Both can be defined and measured for an individual system Either can be chosen to define a complete ensemble QUANTUM MECHANICAL (h>0) Only open systems can be treated– One must choose between them to defineandmeasurean individual system

21. Outline of the Talk: • Some background • information on my approach

22. Traditional View A theory is a conceptual framework providing predictions . The results of experiments or observations decide whether the theory is right or wrong

23. Gaston Bachelard (1884-1962)

24. The Formation of the Scientific Spirit (1938) In order to include new experimental tests, it is necessary to deform the original concepts, study their conditions of applicability, and above all incorporate the conditions of applicability of a concept into the very meaning of the concept.

25. The New Scientific Spirit (translation 1934). [P]henomena must ... be carefully selected, filtered and purified; they must be cast in the mold of scientific instruments and produced at the level of these instruments. Now instruments are just materialized theories. The phenomena that come out of them bear on all sides the mark of theory

26. The Lesson From Bachelard Don’t separate meaning and measurement: Incorporate the conditions of applicability of a concept into the very meaning of the concept!

27. Outline of the Talk: • 2) Measurability Analysis

28. Measurability Analysis Measurability analysis identifies those concepts that a theory defines as meaningful within some context and investigates to what extent the values associated with these concepts are ideally measurable in the defining context (e.g. concepts of hardness and viscosity in the context of fluid and solid states of matter in classical thermodynamics).

29. Peter G. Bergmann Collaborator of Einstein Pioneer in study of quantization of “generally covariant” theories, including GR

30. Bergmann and Smith 1982 Measurability Analysis for the Linearized Gravitational Field “Measurability analysis identifies those dynamic field variables that are susceptible to observation and measurement (“observables”), and investigates to what extent limitations inherent in their experimental determination are consistent with the uncertainties predicted by the formal theory.”

31. Prolegomena to any future QuantumGravity (Stachel2007) ‘[M]easurability analysis’… is based on ‘the relation between formalism and observation’; its aim is to shed light on the physical implications of any formalism: the possibility of formally defining any physically significant quantity should coincide with the possibility of measuring it in principle; i.e., by means of some idealized measurement procedure that is consistent with that formalism.

32. Warning! This is not operationalism– It’s not real because it’s measurable, it must be measurable because it’s real!

33. Simple Classical Example Hardness and Viscosity can be applied to any substance, but not simultaneously. If it is in solid state, hardness applies; if it is in a fluid state viscosity applies.

34. Outline of the Talk: 3)What quantization is and is not

35. What is NOT Being Claimed Quantization only makes sense when applied to “fundamental” structures or entities.

36. The Mystique Surrounding Quantum Mechanics “Anything touched by this formalism thereby seems to be elevated– or should it be lowered?– to a fundamental ontological status. The very words ‘quantum mechanics’ conjure up visions of electrons, photons, baryons, mesons, neutrinos, quarks and other exotic building blocks of the universe.”

37. The Mystique Surrounding Quantum Mechanics (cont’d) “But the scope of the quantum mechanical formalism is by no means limited to such (presumed) fundamental particles. There is no restriction of principle on its application to any physical system. One could apply the formalism to sewing machines if there were any reason to do so!” (Stachel 1986)

38. What IS Quantization? Quantization is just a way accounting for the effects of h, the quantum of action, on any process involving some system,– or rather on theoretical models of such a system-- “fundamental” or “composite”, in which the collective behavior of a set of more fundamental entities is quantized

39. Some Non-fundamental Quanta 1) quasi-particles: particle-like entities arising in certain systems of interacting particles, such as phonons androtonsin hydrodynamics (Landau 1941) 2) phenomenological photons: quantized electromagnetic waves in a homogeneous, isotropic dielectric (Ginzburg 1940)

40. Two Kinds of Relations There are relations, in which the things are primary and their relation is secondary: “relations between things” There are relations, in which the relation is primary while the things are secondary: “things between relations”

41. Particles, Field Quanta The particles of non-relativistic QM and the quanta of special-relativistic Quantum Field Theory lack inherent individuality They are only individuated (to the extent that they are) by some process (Feynman’s word) or phenomenon (Bohr’s word), in which they are involved. Bosons and Fermionscan be arbitrarily permuted without changing the probability amplitude for any process, and so are “things between relations.”

42. Successful Quantization Successful quantization of some classical formalism does not mean that one has achieved a deeper understanding of reality– or better, an understanding of a deeper level of reality. It means that one has successfully understood the effects of the quantum of action on the phenomena (processes)described by the formalism

43. “In my Fathers house are many mansions”-- John 14:2 Having passed beyond the quantum mystique, one is free to explore how to apply quantization techniques to various formulations of a theory without the need to single one out as the unique “right” one. One might say: “Let a hundred flowers blossom, let a hundred schools contend” (Mao 1956)

44. Three Morals of This Tale 1) Relation Between Qantiz’ns If two such quantizations at different levels are carried out, one may then investigate the relation between them Example: Crenshaw demonstrates: “A limited equivalence between microscopic and macroscopic quantizationsof the electromagntic field in a dielectric” [Phys. Rev. A 67 033805 (2003)]

45. Three Morals of This Tale 1) (cont’d) If two such quantizations at the same level are carried out, one may also investigate the relation between them Example: the relation between loop quantization and field quantization of the electromagnetic field: If you “thicken” the loops, they are equivalent (Ashtekar and Rovelli 1992)

46. Three Morals of This Tale 2) Don’t Go “Fundamental” The search for a method of quantizing space-time structures associated with the Einstein equations is quite distinct from: The search for an underlying theory of all “fundamental” interactions

47. Three Morals of This Tale 3) Don’t go “Exclusive” An attempt to quantize one set of space-time structures does not negate, and need not replace, attempts to quantize another set of space-time structures. Everything depends on the utility of the results in explaining some physical processes.

48. The Causality Problem in Atomic Physics, I.I.I.C., Warsaw 1938 The essential lesson of the analysis of measure-ments in quantum theory is thus the emphasis on the necessity, in the account of the phenomena, of taking the whole experimental arrangement into consideration, in complete conformity with the fact that all unambiguous interpretation of the quantum mechanical formalism involves the fixation of the external conditions, defining the initial state of the atomic system concerned and the character of the possible predictions as regards subsequent observable properties of that system (Niels Bohr).

49. “A Well-defined Phenomenon” Any measurement in quantum theory can in fact only refer either to a fixation of the initial state or to the test of such predictions, and it is first the combination of measurements of both kinds which constitutes a well-defined phenomenon.

50. Atomic Physics and Human Knowledge On the lines of objective description, it is indeed more appropriate to use the word phenomenon to refer only to observations obtained under circumstances whose description includes an account of the whole experimental arrangement. In such terminology, the observational problem in quantum physics is deprived of any special intricacy