Can nonrelativistic QM, as used in bound states, be derived from QFT?
115936
Is there a theorem that says that QFT reduces to QM in a suitable limit? A theorem similar to Ehrenfest's theorem?
94896
Deriving a QM expectation value for a square of momentum $\langle p^2 \rangle$
100985
Effect of linear terms on a QFT
105655
Suggested reading for renormalization (not only in QFT)
33669
In what sense is a scalar field observable in QFT?
38103
A No-Nonsense Introduction to Quantum Field Theory
25641
Is there a direct physical interpretation for the complex wavefunction?
54548
Expectation value for $\frac{1}{r}$ in the $|nlm\rangle$ state of hydrogen
67261
How does a perturbation theory make sense in quantum field theory?
58122
QM without complex numbers
147676
Quantised Angular Momentum?
29728
Does the vacuum in QFT have nonzero energy or not?
15275
How do you go from quantum electrodynamics to Maxwell's equations?
55700
Is it possible to recover Classical Mechanics from Schrödinger's equation?
157191
Conjugate Variables, Noether's Theorem and QM
125215
Deriving Schrodinger equation from Klein-Gordon QFT with the definition $\psi(\textbf{x},t)\equiv \langle 0|\phi_0(\textbf{x},t)|\psi\rangle$
99564
Is the Schrödinger equation derived or postulated?