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Results tagged with field-theory
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user 99516
For questions where the dynamical variables are fields, that is, functions of several variables (typically, one time coordinate and several space coordinates). Comprises both classical field theory and quantum field theory. Use this tag when the question applies to both classical and quantum phenomena. Otherwise, use the specific tag instead.
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What is the name of this Lagrangian and how can I find its equations of motion?
I would appreciate if someone tell me how I should go about finding eom. for the following Lagrangian:$$L=-\frac{1}{2}\phi(\Box + m^2)\phi$$
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4
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Lagrangian and finding equations of motion
I am given the following lagrangian:
$L=-\frac{1}{2}\phi\Box\phi\color{red}{ +} \frac{1}{2}m^2\phi^2-\frac{\lambda}{4!}\phi^4$
and the questions asks:
How many constants c can you find for which $\p …
- 385
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Lagrangian and finding equations of motion
Thanks to all you guys I have found that my mistake was at confusing the kinetic and interaction terms. so here is my answer to this question:
this problem is basically finding the values for $\phi$ t …
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expanding the coulomb lagrangian [duplicate]
suppose we have the free field lagrangian:
$$L=-\frac{1}{4}F_{\mu \nu} ^2$$ then its just $$L=-\frac{1}{4}(\partial_\mu A_\nu -\partial_\nu A_\mu)^2$$ what I don't understand is how its equal to: $$L= …
- 385
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2
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How to expand Maxwell Lagrangian?
I am given $$L=-\frac{1}{4}F^2_{\mu\nu}-A_{\mu\nu}J_\mu$$ to calculate equations of motion I have to expand the terms in the Lagrangian as following (note this is from Schwartz QFT book page 37):
$$L= …
- 385
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Finding Dirac Hamiltonian from Dirac equation [duplicate]
My question is can we get the Hamiltonain from Dirac Equation?
We have the following for Dirac equation:
$$(i\gamma ^\mu \partial_\mu-m)\phi=0.$$
Then separating the time and space components:
$$( …
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