Talk:Matrix mechanics/Archive 1

Right term?

" But the principle of uncertainty (also called complementarity by Bohr) holds for most other pairs of observables too."

I suppose it would be possible to justify this position somehow, but I suspect that the writer actually meant to write "also called indeterminacy by Heisenberg". P0M (talk) 13:47, 24 June 2009 (UTC)

All I meant was to link to complementarity, and mention Bohr. It was Bohr who wanted Heisenberg to explain [x,p]=i in a physical way, and once Heisenberg did that, it was Bohr who turned the resulting uncertainty principle into a full fledged philosophy, designed to replace determinism. Bohr was keener on the uncertainty principle than Heisenberg, I think because it was more visualizable than canonical commutators, and Bohr always worked with physical pictures (like the liquid drop nucleus). Bohr goes on to analyze thought experiments with the electromagnetic field to establish that it has the same kinds of uncertainty relations, so that it is quantized in the same way as a mechanical system, with field commutators derived from the Lagrangian. Dirac and Heisenberg just assumed this without worrying too much about establishing everything with careful thought experiments. Without the physical arguments of Bohr and Rosenfeld, it is not clear to me that canonical quantization would have been accepted so quickly for quantities like the electromagnetic field where the commutation relations were harder to interpret directly. The construction of the Hilbert space by Dirac and Fock requires gauge fixing, and other formal annoyances, which would make it difficult to be sure that everything is all right. It seems that physical pictures were less important to Heisenberg and Dirac, who could just see from the formalism that everything was all right.Likebox (talk) 18:48, 15 July 2009 (UTC)

Actually, I was wrong. Bohr does use "complementarity" where Heisenberg would have used indeterminacy. P0M (talk) 19:01, 16 July 2009 (UTC)