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New answers tagged quantum-electrodynamics

5

The magnetic moment of the electron is a magnetic moment, so the right magnetic field around it is $$\mathbf{B}({\mathbf{r}})=\nabla\times{\mathbf{A}}=\frac{\mu_{0}}{4\pi}\left(\frac{3\mathbf{r}(\mathbf{\mu}\cdot\mathbf{r})}{r^{5}}-\frac{{\mathbf{\mu}}}{r^{3}}\right).$$ The world is quantum mechanical – and so is any viable description of the spin – so we ...

0

Until an expert in this field gives a rigorous answer to your question, I will give you my view. If I understand correctly your questions, you are on the one hand asking about other types of existing exchange interactions between virtual particles and real particles, and on the other hand you claim that using the usual virtual photon picture for the ...

1

To get a better understand of what is going on, take a look at the plot below, also linked here: http://en.wikipedia.org/wiki/File:Dispersion_Relationship.gif What the author meant by "letting the speed of light go to infinity" is that the we let the slope of the blue line become infinite. In that case, the solid red line would not curve as shown below, ...

3

Feynman diagrams are more than just the Lagrangian. They can be acquired by expanding the path integral of the theory into a perturbative series. There is a priori no reason to assume that all quantities needed in order to produce sensible results are consistent with gauge invariance. One possible issue is the problem of regularization: the way your ...

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I assume the first part, up to But how exactly does it happen? defines and explains your question, and then you show what you think about it so far? It looks like the point where it goes wrong is about what the inductor does. There is nothing about "split-second" and relativistic, it behaves in a pretty symmetric way to the capacitor. It's "dynamic" ...

4

Virtual particles are not real It's in the name. You may draw Feynman diagrams where there are internal lines, and we call these internal lines virtual particles. They are not real. You will never detect a virtual particle. They are not really exchanged between the real charged particles. Virtual particles are a just-so stories designed to explain Feynman ...

2

We don't really understand why charge is quantized. Nor we do know if there ought to be magnetic monopoles. These two things seem linked. Dirac gave an argument for charge quantization in the early days, but this presupposed the existence of a magnetic monopole. In Maxwell's equations, it would be completely natural to imagine the existence of magnetic ...

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Because QED in $D=2$ is a confining theory and as such it develops mass gap. The coulomb potential in $D=2$ is linear with the distance of the charges. It is one of the few exactly solvable confining QFT theories. Perhaps, I should add that by gauge invariance one can always fix $A_x=0$ while for the other component, $A_t$, the equations of motion give ...

1

This is where virtual particles come into play. http://youtu.be/K6i-qE8AigE?t=3m23s Essentially you can think of these virtual particles as temporary photons as carriers that dont exactly behave ver well with conservation of energy. The field is full of these non-conservative carriers for a very brief instant as a function of the mass of the carrier ...

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If you had a neutral plasma (which can be the free charges in a metal) and you pulled the negative and positive charges apart and let them go, they would oscillate due to the electrostatic potential. This is an excitation known as a plasma oscillation. A Plasmon is the quasiparticle associated with plasma oscillations (analogous to phonons being the ...

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There's no difference between plasmon and plasmon polariton. Both of them indicate the resonant excitations involving electromagnetic wave and collective electronic motions simultaneously. "surface" stresses that the excitation in many cases occurs at the interface of a metal and a dielectric. However, there exist bulk plasmons as well. So "surface ...

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