- 1859-1900: see Section "Black-body radiation experiment". Continuously improving culminating in Planck's law black-body radiation and Planck's law
- 1905 photoelectric effect and the photon
- TODO experiments
- 1905 Einstein's photoelectric effect paper. Planck was intially thinking that light was continuous, but the atoms vibrated in a discrete way. Einstein's explanation of the photoelectric effect throws that out of the window, and considers the photon discrete.
- 1913 atomic spectra and the Bohr model
- 1885 Balmer series, an empirical formula describes some of the lines of the hydrogen emission spectrum
- 1888 Rydberg formula generalizes the Balmer series
- 1896 Pickering series makes it look like a star has some new kind of hydrogen that produces half-integer entries in the Pickering series
- 1911 Bohr visits J. J. Thomson in the University of Cambridge for his postdoc, but they don't get along well
- Bohr visits Rutherford at the University of Manchester and decides to transfer there. During this stay he becomes interested in problems of the electronic structure of the atom.
- 1913 february: young physics professor Hans Hansen tells Bohr about the Balmer series. This is one of the final elements Bohr needed.
- 1913 Bohr model published predicts atomic spectral lines in terms of the Planck constant and other physical constant.
- explains the Pickering series as belonging to inoized helium that has a single electron. The half term in the spectral lines of this species come from the nucleus having twice the charge of hydrogen.
- 1913 March: during review before publication, Rutherford points out that instantaneous quantum jumps don't seem to play well with causality.
- 1916 Bohr-Sommerfeld model introduces angular momentum to explain why some lines are not observed, as they would violate the conservation of angular momentum.
Introductory Quantum Mechanics by Richard Fitzpatrick (2020) by 
Ciro Santilli 37 Updated 2025-07-16
Ciro Santilli 37 Updated 2025-07-16This LibreTexts book does have some interest!
MIT 8.06 Quantum Physics III, Spring 2018 by Barton Zwiebach by Ciro Santilli 37 Updated 2025-07-16
Ciro Santilli 37 Updated 2025-07-16Instructor: Barton Zwiebach.
Free material from university courses:
- physics.weber.edu/schroeder/quantum/QuantumBook.pdf (archive) "Notes on Quantum Mechanics" pusbliehd by Daniel V. Schroeder (2019) The author is from from Weber State University.
Summary:
- Chapter 2 "Band Structure" covers electronic band theory
Looks very impressive! Last update marked 2011 as of 2020.
Goes up to "A.15 quantum field theory in a Nanoshell", Ciro have to review it to see if there's anything worthwhile in that section.
Personal page says he retired as of 2020: www.eng.fsu.edu/~dommelen/ But hopefully he has more time for these notes!
And he appears to have his own lightweight markup language that transpiles to LaTeX called l2h: www.eng.fsu.edu/~dommelen/l2h/
Last updated: 2013.
There were apparently some lecture videos at: web.archive.org/web/20030604194654/http://physicsstream.ucsd.edu/courses/spring2003/physics130a/ as pointed out by Matthew Heaney[ref], .mov files can be found at: web.archive.org/web/*/http://physicsstream.ucsd.edu/courses/spring2003/physics130a/*, but we were yet unable to open them, related:
These are the key mathematical ideas to understand!!
There are actually a few formulations out there. By far the dominant one as of 2020 has been the Schrödinger picture, which contrasts notably with the Heisenberg picture.
Another well known one is the de Broglie-Bohm theory, which is deterministic, but non-local.
TODO: use the results from the quantum harmonic oscillator solution to precisely illustrate the discussion at Schrödinger picture with a concrete example.
The idea the the wave function of a small observed system collapses "obviously" cannot be the full physical truth, only a very useful approximation of reality.
Because then are are hard pressed to determine the boundary between what collapses and what doesn't, and there isn't such a boundary, as everything is interacting, including the observer.
The many-worlds interpretation is an elegant explanation for this. Though it does feel a bit sad and superfluous.
One single universal wavefunction, and every possible outcomes happens in some alternate universe. Does feel a bit sad and superfluous, but also does give some sense to perceived "wave function collapse".
Pinned article: Introduction to the OurBigBook Project
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