Search Results
| Search type | Search syntax |
|---|---|
| Tags | [tag] |
| Exact | "words here" |
| Author |
user:1234 user:me (yours) |
| Score |
score:3 (3+) score:0 (none) |
| Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
| Views | views:250 |
| Code | code:"if (foo != bar)" |
| Sections |
title:apples body:"apples oranges" |
| URL | url:"*.example.com" |
| Saves | in:saves |
| Status |
closed:yes duplicate:no migrated:no wiki:no |
| Types |
is:question is:answer |
| Exclude |
-[tag] -apples |
| For more details on advanced search visit our help page | |
Results tagged with lagrangian-formalism
Search options not deleted
user 47373
For questions involving the Lagrangian formulation of a dynamical system. Namely, the application of an action principle to a suitably chosen Lagrangian or Lagrangian Density in order to obtain the equations of motion of the system.
2
votes
Lagrangian for massless fermions and associated currents
I haven't opened the link, but I guess that the field transformation you are writing is a global symmetry (SU(2)) action, which means that Pauli matrices act on a different space than the gamma matric …
- 2,237
4
votes
0
answers
81
views
Decomposition of rank-2 field and local interactions
Any rank-2 tensor can be decomposed in the following way
$$
\phi_{\mu\nu} =\phi_{\mu\nu}^{TT} + \partial_{(\mu}\xi_{\nu)} +\frac{1}{4}T_{\mu\nu}s+\frac{1}{4}L_{\mu\nu}(w-3s)
$$
where $\phi_{\mu\nu}^ …
- 2,237
4
votes
Vertex factor for $\frac{g}{4} (A_{\nu}A^{\nu})^2$ in QED
You can write the interaction as
$$
\frac{g}{4} A^\rho A^\nu A^\sigma A^\mu g_{\rho \nu} g_{\sigma \mu}
$$
Suppose you have a 4-point function to compute with the following external polarization vec …
- 2,237
4
votes
1
answer
275
views
Calculation of gravitational Euclidean action of Schwartzchild BH
I am reading the paper of Gibbons and Hawking Action integrals and partition functions in quantum gravity, Phys. Rev. D 15 (1977) 2752 where they compute the gravitational action of black holes.
In pa …
- 2,237
1
vote
0
answers
282
views
Relation between interaction Lagrangian and interaction Hamiltonian
I work with this interaction Lagrangian density
$$\mathcal{L}_{int} = ia\bar{\Psi}\gamma^\mu\Psi Z_\mu +ib(\phi^\dagger\partial_\mu \phi - \partial_\mu\phi^\dagger \phi)Z^\mu,$$
where $Z^\mu$ is an …
- 2,237
1
vote
0
answers
373
views
Generating functional for free and interacting theories [closed]
I'm asking probably a stupid question.
We define the generating functional for free theories as
$$
Z_0[J] = \int D \psi e^{i\int d^4x \left[ L_0(x) + J_l(x)\psi^l(x) \right]}
$$
with $L_0$ the free l …
- 2,237
2
votes
2
answers
134
views
Degrees of freedom of a constrained vector
I have to handle with this lagrangian of a real vector $\chi^\mu$
$$
\mathcal{L} = -\frac{1}{4}F_{\mu\nu}^2 + B^\mu \square \chi_\mu + C\, \partial_\mu \chi^\mu + \mathcal{L}_{int}
$$
where $B^\mu$ …
- 2,237
1
vote
1
answer
438
views
Field redefinition of gauge fields
Let us consider the non-abelian gauge theory $SU(3)_c \times SU(3)$ where the groups are treated as different but the couplings are taken equal. Let us suppose we have a mixing term among the field-st …
- 2,237