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Both Heisenberg and Schrödinger found each other's way of formulating Quantum Mechanics quite repellent.

My question is: Did any of the two change their views towards each other (specially Heisenberg)? Did he eventually accept Schrödinger's formulation or relax his attitude towards it, specially considering that both formulations were shown to be mathematically equivalent?

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    $\begingroup$ After Schrödinger showed mathematical equivalence only the difference in interpretation remained. However, debates in Copenhagen soon showed that both interpretations (with jumps or waves) were unsatisfactory. After Born proposed his rule and the Copenhagen interpretation was developed they were both discarded, and the issue became moot, see Quantum Mechanics 1925-1927. $\endgroup$ – Conifold Mar 26 '20 at 5:13
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    $\begingroup$ What is the evidence that any of them considered the other interpretation "repellent"? $\endgroup$ – Alexandre Eremenko Mar 26 '20 at 11:00
  • $\begingroup$ @AlexandreEremenko, the link given by Conifold quotes Heisenberg as stating that Shrodinger's theory is repulsive. In general scientists seem to adhere strongly to interpretations which suit their broader philosophical (and often political) views. $\endgroup$ – Steve Mar 26 '20 at 18:38
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    $\begingroup$ Heisenberg's "attitude" about the wave formulation is vastly exaggerated. By 1929 he was lecturing in great detail on Schroedinger's equation at the University of Chicago, and next year he published his classic introductory book The Physical Principles of the Quantum Theory covering it extensively. $\endgroup$ – Cosmas Zachos Mar 27 '20 at 16:20
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    $\begingroup$ @steve: He doesn't say "repellant" which carries negative connotations such as disgust and the like; what he does say is "but I felt discouraged, not to say repelled, by the methods of transcendental algebra, which appeared difficult to me, and by the lack of visualizability"; being 'repelled' by something because you find it 'difficult' and 'unvisualisable' doesn't imply disgust. $\endgroup$ – Mozibur Ullah Mar 28 '20 at 11:47
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Heisenberg's "attitude" about the wave formulation of QM is vastly exaggerated. By 1929 he was lecturing in great detail on Schrödinger's equation at the University of Chicago, and next year he published his classic introductory book The Physical Principles of the Quantum Theory covering it extensively. He understood that, as the virtual initiator of the field, he had to cover its huge span, and was in close touch with both Jordan and Dirac who explored the link between the two formulations much more thoroughly than Schrödinger. This mature attitude is already reflected in the advice he gave to graduate student Dirac in 1925.

Quoting from The Strangest Man -— The Hidden Life of Paul Dirac, Mystic of the Atom by Graham Farmelo (Basic Books, 2009),

At first, Dirac was annoyed by Schrödinger’s theory, as he resented even the thought of suspending work on the new quantum mechanics and starting afresh. But in late May, as he was finishing the writing of his Ph.D. thesis, he received a persuasive letter from Heisenberg urging him to take Schrödinger’s work seriously. This wise advice was ironic coming from Heisenberg, an opponent of the rival theory, who had written to Wolfgang Pauli in early June, ‘The more I reflect on the physical portion of Schrödinger’s theory the more disgusting I find it. What Schrödinger writes on the visualizability of his theory is probably not quite right. In other words, it’s crap.’ Schrödinger gave as good as he got, dismissing the mathematical arcana of Heisenberg’s theory and the idea of quantum jumps. The two theorists clashed unpleasantly when they first met a month later at a packed seminar in Munich, the first skirmish in what was to be a long and acrimonious dispute.

Dirac ignored Schrödinger’s theory in his Ph.D. thesis, ‘Quantum Mechanics’, the first to be submitted anywhere on the subject. [...]

In very short order, Dirac would go on to make trenchant contributions to formulating the time-dependent Schrödinger equation.

Heisenberg's "attitude" is not entirely unwarranted. The community at the time was far more conversant with differential equations than with matrix techniques, an accidental mathematics education shortcoming, giving the wave formulation an instant popular advantage. Nevertheless, matrix techniques have ultimately triumphed over a century; connections to classical mechanics, such as phase-space quantization are quite closer to the matrix mechanics spirit than to wave functions. In fact, Dirac's fusion language has made the two formulations virtual "dialects" of the same formal structure, routinely used side-by-side.

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  • $\begingroup$ Ph.D. thesis, ‘Quantum Mechanics’, the first [June 1926] to be submitted anywhere on the subject --- I don't know how significant this is, but the ring theorist Neal Henry McCoy (1905-2001) wrote a Ph.D. dissertation, On Commutation Formulas in the Algebra of Quantum Mechanics (iii + 30 pages, dated June 1929), under the general topologist Edward Wilson Chittenden. I have a .pdf scan of McCoy's dissertation if anyone is interested (my email is at my profile information). $\endgroup$ – Dave L Renfro Feb 25 at 18:54
  • $\begingroup$ @Dave. By that time (1929), there were dozens of theses on the new-fangled field: time moved fast in those years, indeed... $\endgroup$ – Cosmas Zachos yesterday
  • $\begingroup$ I figured as much, but the fact that the dissertation was by someone known for his work and books in ring theory, and advisor for his work in the early years of general topology, makes this a bit interesting I think. $\endgroup$ – Dave L Renfro yesterday

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