All Questions
Tagged with equations-of-motion path-integral
5 questions
1
vote
0
answers
143
views
Does the path integral approach to QFT have equations of motion? [duplicate]
In the canonical quantization approach for QFT, we deal with operators & their (anti)commutation relations. However, at the same time, we say that the field operators are the solutions of equation ...
- 454
4
votes
2
answers
575
views
Conceptual question about Euler-Lagrange equations in Quantum Field Theory
So I've started going down the QFT rabbit hole aided by Schwartz's book "Quantum Field Theory and the Standard Model". On chapter 7, the first method used to find the position-space Feynman ...
- 409
7
votes
3
answers
1k
views
Euler-Lagrangian equation of motion of quantum fields in QFT
A canonical way of doing quantum field theory is by starting with some Lagrangian, for example, that of free scalar field
$$L=\frac{1}{2}\partial_{\mu}\phi \partial^{\mu}\phi-\frac{1}{2}m\phi^2$$
Then ...
- 462
5
votes
2
answers
1k
views
What the role of classical equation of motion in quantum field theory?
I've learnt quantum field theory for a semester but I still can't understand the role of classical equation of motion in QFT.
I have looked up for several books. They all discuss classical field ...
- 189
7
votes
1
answer
641
views
Can I really take the classical field equations at face value in QFT?
To be concrete, let's say I have a relativistic $\phi^4$ theory [with Minkowski signature $(+,-,-,-)$]
$$
\tag{1} \mathcal{L} ~=~ \frac{1}{2} \left ( \partial_{\mu} \phi \partial^{\mu} \phi - m^2 \...
- 71