This post on a list of books for understanding the non-relativistic QM points out that QM is vast, and that it takes a prolonged, sustained effort to learn it. There are many resources you could use for learning QM, like wikipedia, SEP, modern physics books, (quantum) chemistry books, real (introductory) quantum physics books, solid state physics books, original articles, or expositions for a general audience by famous physicists. No matter how you approach it, using more than a single resource and finding resources which suit you personally to the point that you are willing to spend an extended period of time with them will be important.
However, at least for me, there was also another problem:
Let me be honest myself how much I really understand the consistent histories approach. In 1998, I had to endure a QM 1 course at university, and I didn’t manage to connect at all to QM. (I did get those spherical harmonics and Laguerre polynomials, operators acting on functions, commutativity, Hermitian vs. self-adjoint, and other mathematical techniques, but I couldn’t create a picture or film in my head of how to use this to describe nature. My favourite defence was to ask others to explain the Compton effect to me in terms of that stuff – or any other simple interaction between electrons and light which can be observed.) Occasional attempts to read material discussing interpretation of QM failed quite early, I couldn’t penetrate into the material and words at all. Around 2005, I read (or rather browsed) “Understanding Quantum Mechanics” by Roland Omnès, and it was the first time that I felt that the material was presented in a way that I would understand it, if I invested the time to work through it. It felt like “let me calculate and explain” as opposed to “don’t ask questions, nobody understands QM anyway”.
The first time I had some real idea about how QM could make sense was after spending time with
- Max Born, Emil Wolf: Principles of Optics
especially the part about statistical optics and partial coherence. Concepts like the coherency matrix and Stokes parameters or rather similar continuous concepts clarified for me how the instrumentalistic approach works in practice, and why it can be preferable even in cases where an ontological approach is (still) possible. However, since spending time on statistical optical would probably be too wasteful, reading the Nobel lecture of Max Born and learning a bit about the density matrix (especially how it allows to describe subsystems) will hopefully be just as illuminating.
Since we are talking about reading texts from the founding fathers of QM: Werner Heisenberg, Erwin Schrödinger, Paul Dirac, and Richard Feynman all write very clear. The books
are easy to read and teach a lot about QM. The Hanbury Brown and Twiss effect described in passing at the end of chapter 2 in Feynman's QED book made me accept that my convenient instrumentalistic picture of statistical optics misses some effects that the less convenient ontological picture predicts correctly. Those books didn't require much math. More math is required for learning the basics of quantum mechanics.
are timeless books, but many other real (introductory) quantum physics will teach the basics too. Just keep on trying until you find books which suit you personally, and don't shy away from books in your native language. You can still read those timeless books after you understood the basics. Then you may also better appreciate the answers those books give to fundamental questions which your other books didn't bother to mention. Many very readable original articles, including the "cat" paper and the "Are There Quantum Jumps?" paper can be found at the end of the
With this, let me leave the founding fathers of QM behind, and return to my personal experiences. Bob Doyle's site contain ton's of original material and relevant excerpts clarifying the positions of many different philosophers and scientists regarding QM and other topics. One unknown book which helped me is
... much of the interpretive work Teller undertakes is to understand the relationship and possible differences between quantum field-theory — i.e., QFT as quantization of classical fields - and quantum-field theory — i.e., a field theory of ‘quanta’ which lack radical individuation, or as Teller says, “primitive thisness.”
I’m not a physicist. My degree is in mathematics, I am an amateur logician, and I do read philosophical articles and books. I am an instrumentalist with respect to non-cosmological (quantum) physics, but not the caricature version that people unhappy with Copenhagen evoke. I prefer "let me calculate and
explain" interpretations of quantum mechanics over "let me convince
you that the whole universe is described by a single wavefunction"
interpretations of quantum field theory.