The passage from the undergraduated course of quantum mechanics and the first course of qft was plenty traumatic: usual concepts like the hamiltonian of a system with its energy eigenstates, orbital angular momentum, the uncertainty principle and so on seemed to me vanished in this new framework. Moreover, some unanswered questions from the undergraduated course like the decay of an excited electron into the ground state with a photon emission still remained obscure. During the past months I was able to link something, but it's more like of having a big hole from the last section of NRQM and the quantization of fields. Furthermore, our QFT courses mostly focussed on scattering theory and renormalization, which is good, but left so many topics behind. So what I'm asking you is if there is a book, or a collection of books to follow for closing all these gaps in my knowledge. I know that this sounds like the nth-related post on QFT books, but I tryed many of them and they seems all so "self referenced". For example, Maggiore is like a short summary of the state of the art, Srednicki is good if you need to check something but you dont need to go deep, Schwartz seems to have forget what does it mean to learn from zero this subject; Zee offers some hint, but it misses this "bridge"-like behaviour which I'm asking. The only relevant book I think it's made for that purpose is Weinberg, but for a newcomer it seems rally unreadable with all that ugly and gory notation. Hoping to get answers and good advices and that this post will be useful for people like me who are trying to understand QFT beyond the LSZ formula

The passage from the undergraduated course of quantum mechanics and the first course of qft was plenty traumatic: usual concepts like the hamiltonian of a system with its energy eigenstates, orbital angular momentum, the uncertainty principle and so on seemed to me vanished in this new framework. Moreover, some unanswered questions from the undergraduated course like the decay of an excited electron into the ground state with a photon emission still remained obscure. During the past months I was able to link something, but it's more like of having a big hole from the last section of NRQM and the quantization of fields. Furthermore, our QFT courses mostly focussed on scattering theory and renormalization, which is good, but left so many topics behind. So what I'm asking you is if there is a book, or a collection of books to follow for closing all these gaps in my knowledge. I know that this sounds like the nth-related post on QFT books, but I tryed many of them and they seems all so "self referenced". For example, Maggiore is like a short summary of the state of the art, Srednicki is good if you need to check something but you dont need to go deep, Schwartz seems to have forget what does it mean to learn from zero this subject; Zee offers some hint, but it misses this "bridge"-like behaviour which I'm asking. The only relevant book I think it's made for that purpose is Weinberg, but for a newcomer it seems rally unreadable with all that ugly and gory notation. Hoping to get answers and good advices and that this post will be useful for people like me who are trying to understand QFT beyond the LSZ formula.

Edit: so as far as I can understand, first of all I have to go through a good book of RQM which doesnt simply show me all types of relativistic eqs. Then I should turn to the first 5 chapters of Weinberg and "lose" time over them to get solid foundations. Then I can go for I&Z to get the feeling of the qft mindset. Given those, I should be able to appreciate better the books I have cited. If anybody else wants to share his/her experience it would be appreciated and welcomed.