3 ms·

Famously there is no consensus of how to interpret the equations of quantum mechanics, which naturally restricts introductory discussion to the mathmatical aspe

Famously there is no consensus of how to interpret the equations of quantum mechanics, which naturally restricts introductory discussion to the mathmatical aspects.

forkandwait 8y ago
I think there is a ton of consensus on how the equations predict lab results, however, and I would be very happy with that.
- jabl 8y ago
  For practical uses the "shut up and calculate" interpretation of QM works just fine. For a recent head-scratcher, though, see https://www.nature.com/articles/s41467-018-05739-8 https://www.nature.com/articles/s41467-018-05739-8
  - kgwgk 8y ago
    There was some discussion about that paper here: https://news.ycombinator.com/item?id=18023452 https://news.ycombinator.com/item?id=18023452 I think it's much less interesting than it seems at first sight. Related (and clearer): In Defense of a "Single-World" Interpretation of Quantum Mechanics (Jeffrey Bub) https://arxiv.org/abs/1804.03267 https://arxiv.org/abs/1804.03267
kgwgk 8y ago
I'm not sure the lack of consensus is the reason. One can learn QM and use it for a whole career without ever worrying about these issues. I'm not sure why do you mean by "introductory discussion" but I think "popular science" books focus mostly on the controversial parts. At the university level, at least in my experience, you study a lot of classical physics, early quantum physics (1900-1925), and mathematical physics before taking a first look at Quantum Mechanics (Schroedinger/Heisenberg). And you may never be exposed to the relativistic extensions.
- SiempreViernes 8y ago
  I meant the discussion in the intro courses; Griffiths just plonks down the Schrodinger equation on page one and you just have to eat it. In contrast a textbook about thermodynamics will be all steam engines at the start, or maybe talk about a thermometer. Solid, sensible things and no talk about Gibbs free energy or any of the deep theory that exists. You could start a QM book talking about the double slit experiment, but would have to write a lot of "one interpretation" and "some views say this". Or you could just brazenly pretend there is no controversy and make every reader that knows of it very suspicious indeed.
  - andrepd 8y ago
    >You could start a QM book talking about the double slit experiment That is indeed how my favorite QM book starts: Cohen-Tannoudji. See also Landau for one that starts from experiment and not theory.
    - kgwgk 8y ago
      Yes, but it quickly cuts to the meat :-) (I mean C-T/D/L, that’s the book I was talking about in a sibling comment)
  - kgwgk 8y ago
    I’m not familiar with that book. I learnt QM from a 2-volume, 1500 pages book that gives you Schroedinger’s equation 10 pages in. But that book made no claim of being “introductory” and I previously had a “quantum physics” course including the different things that lead to Schroedinger’s equation (Plank, Rutherford, Bohr, etc). In any case introductory books that discuss the physics and not just the mathematics do also exist, like vol 3 in Feynman’s lectures. Edit: I’m looking at Griffiths’ book and after defining Schroedinger’s equation in section 1.1 he devotes three pages to discussing its statistical interpretation in section 1.2 and mentions different interpretations, the Bell inequalities and the measurement problem. He comes back to these philosophical issues at the end of the book in a 12-page afterword.

Famously there is no consensus of how to interpret the equations of quantum mechanics, which naturally restricts introductory discussion to the mathmatical aspects.

forkandwait 8y ago

I think there is a ton of consensus on how the equations predict lab results, however, and I would be very happy with that.

jabl 8y ago
For practical uses the "shut up and calculate" interpretation of QM works just fine. For a recent head-scratcher, though, see https://www.nature.com/articles/s41467-018-05739-8 https://www.nature.com/articles/s41467-018-05739-8
- kgwgk 8y ago
  There was some discussion about that paper here: https://news.ycombinator.com/item?id=18023452 https://news.ycombinator.com/item?id=18023452 I think it's much less interesting than it seems at first sight. Related (and clearer): In Defense of a "Single-World" Interpretation of Quantum Mechanics (Jeffrey Bub) https://arxiv.org/abs/1804.03267 https://arxiv.org/abs/1804.03267

kgwgk 8y ago

I'm not sure the lack of consensus is the reason. One can learn QM and use it for a whole career without ever worrying about these issues. I'm not sure why do you mean by "introductory discussion" but I think "popular science" books focus mostly on the controversial parts. At the university level, at least in my experience, you study a lot of classical physics, early quantum physics (1900-1925), and mathematical physics before taking a first look at Quantum Mechanics (Schroedinger/Heisenberg). And you may never be exposed to the relativistic extensions.

SiempreViernes 8y ago
I meant the discussion in the intro courses; Griffiths just plonks down the Schrodinger equation on page one and you just have to eat it. In contrast a textbook about thermodynamics will be all steam engines at the start, or maybe talk about a thermometer. Solid, sensible things and no talk about Gibbs free energy or any of the deep theory that exists. You could start a QM book talking about the double slit experiment, but would have to write a lot of "one interpretation" and "some views say this". Or you could just brazenly pretend there is no controversy and make every reader that knows of it very suspicious indeed.
- andrepd 8y ago
  >You could start a QM book talking about the double slit experiment That is indeed how my favorite QM book starts: Cohen-Tannoudji. See also Landau for one that starts from experiment and not theory.
  - kgwgk 8y ago
    Yes, but it quickly cuts to the meat :-) (I mean C-T/D/L, that’s the book I was talking about in a sibling comment)
- kgwgk 8y ago
  I’m not familiar with that book. I learnt QM from a 2-volume, 1500 pages book that gives you Schroedinger’s equation 10 pages in. But that book made no claim of being “introductory” and I previously had a “quantum physics” course including the different things that lead to Schroedinger’s equation (Plank, Rutherford, Bohr, etc). In any case introductory books that discuss the physics and not just the mathematics do also exist, like vol 3 in Feynman’s lectures. Edit: I’m looking at Griffiths’ book and after defining Schroedinger’s equation in section 1.1 he devotes three pages to discussing its statistical interpretation in section 1.2 and mentions different interpretations, the Bell inequalities and the measurement problem. He comes back to these philosophical issues at the end of the book in a 12-page afterword.