All Questions
4
questions
5
votes
0
answers
78
views
How many Lagrangians can a QFT have?
I just stumbled across a presentation by Tachikawa about "What is Quantum Field Theory". He has an interesting perspective that we should think of (at least a subset of) quantum field ...
- 1,014
4
votes
0
answers
60
views
Thermodynamic free energy of interacting system
This question concerns an interacting system's thermodynamic free energy $\Omega$. Generally speaking, The action $S$ for an interacting system has the following form:
\begin{equation}
S(\phi,\psi) = ...
- 2,038
1
vote
0
answers
159
views
Connected part of $S$-matrix generating functional
I am currently studying an article by A.Jevicki et. al. (https://doi.org/10.1103/PhysRevD.37.1485) and I am a little confused. They say that the generating functional of the $S$-matrix is related to ...
- 93
0
votes
0
answers
112
views
Derivative of the functional partition function relating to non-linear sigma model
On the page of 457 of condensed matter field theory by Altand and Simons, the authors give the partition function
$$Z = \int Dg e^{-S[g]},$$
where
$$
S[g] = \frac{1}{\lambda}\int{d^dr\; \textrm{tr}[\...
- 227