# Feynman's book: Quantum Mechanics and Path Integrals

Hello,

I tried to read Feynman's book: Quantum Mechanics and Path Integrals but it is so difficult. Is it a really important book if you want to learn Quantum Mechanics? If so what should I do in preparation to read it?

Thanks

Well, typically people don't start right away with Feynman's path integrals.
They will become important if you want study QFT, so they're typically tackled after finishing undergrad level QM courses.

You are also expected to have a working knowledge of classical mechanics before e.g. Lagrangian & Hamiltonian mechanics.

A basic book on QM which also has a chapter on path integrals:

https://www.amazon.com/dp/0199560277/?tag=pfamazon01-20&tag=pfamazon01-20

So to answer your question if its important or not for beginners, then I would say No.

Last edited by a moderator:
Hello,

I tried to read Feynman's book: Quantum Mechanics and Path Integrals but it is so difficult. Is it a really important book if you want to learn Quantum Mechanics? If so what should I do in preparation to read it?

Thanks
Disclaimer: I am not a Quantum Mechanic / Quantum Physician / anything of the sort.

I too have long found Feynman / Hibbs to be pretty opaque (once you get past the introductory chapters at least). However, I haven't ever found myself blocked off from reading other books on theoretical physics because of this; the path integral formulation is usually not covered until long after the other two formulations, due to the more advanced ideas required (though I don't really think functional integration is that much more advanced than the prerequisites for the Heisenberg interpretation -- Lie / representation theory, Hilbert spaces, Fourier analysis...but I guess with the Heisenberg formulation you don't really need to see all of that). The results are totally equivalent, but it's useful in relativistic settings, because of its manifest covariance...however, even there it's mostly used as a stepping stone to a proof, rather than an integral (pun intended) part of the material.

Having said that, it can't hurt to be familiar with the concepts; the Wikipedia's page on the Path Integral Formulation is a gem (though some bits struck me as slightly hand-wave-y) and should give you enough to continue your studies (unless, say, you're taking a course where Feynman/Hibbs is required reading).