All Questions
Tagged with electromagnetism perturbation-theory
15
questions
5
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1
answer
3k
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Meaning of dipole approximation for selection rules
This is a really tough one:
I would like to understand what it really means to apply the dipole approximation when deriving the selection rules. This question is purely about intuitive understanding ...
3
votes
0
answers
101
views
Perturbative Techniques In Finding Electric Field of Symmetric Distributions
Lets say we have a uniform sphere of charges at the origin (at retarded time = 0) with some velocity and we are interested in the field at a point along the x-axis (normal to the surface of the sphere)...
3
votes
2
answers
5k
views
The stark effect on ground state of Hydrogen
When considering the Stark Effect, we consider the effect of an external uniform weak electric field which is directed along the positive $z$-axis, $\vec{\varepsilon} = \varepsilon \vec{k}$, on the ...
2
votes
1
answer
170
views
What would happen if the fine structure constant were set to 1?
While reading up on magnetic monopoles, I have been led to understand that, due to S-duality, the magnetic equivalent of the fine-structure constant, $\alpha_M$ must be related to the reciprocal of $\...
2
votes
0
answers
753
views
How to express the wavefunction of a harmonic oscillator in a perturbing electric field?
So I am looking at the problem of the (charged) harmonic oscillator in a weak electric field - the problem that defines e.g. the polarizibility of the oscillator.
Let the fieldless Hamiltonian be:
$...
2
votes
0
answers
208
views
Second-order correction in Quantum-Confined Stark effect
In the wikipedia article, there is a second-order correction in the Quantum-Confined Stark Effect. I could not understand how it was solved. I did not understand the meaning of 2(0) and 1(0) and how I ...
2
votes
0
answers
421
views
Splitting of degenerate energy levels with a perturbed particle in a box
Suppose you have a particle in a square box $[0,L]\times[0,L]$. As the box is a square, the (2,1) and (1,2) eigenfunctions will have the same energy. If you were to apply an oscillating electric field ...
1
vote
1
answer
150
views
Why the perturbation Hamiltonian of induced dipole in field still $ d \cdot E$? [closed]
We used to calculate the potential energy of permanent dipole in the uniform field is like $-p \cdot E$ ... and when we put a perturbation Hamiltonian of an external field on the neutral atom, that ...
1
vote
1
answer
102
views
Perturbation of central field potential
i`d like to consider system with Coulomb potential: $U = -\frac{\alpha}{r}$ and constant magnetic field.It is easy to write Lagrangian function:
$$ L = \frac{m}{2}(\dot{\rho}^2 + \rho^2\dot{\phi}^2) + ...
1
vote
0
answers
38
views
Can all classical optical materials be described by perturbation theory?
In quantum field theory (e.g. lattice QED), perturbation theory can "break down" when interactions become too strong.
Can something like that happen in classical non-linear optics? Can there ...
1
vote
0
answers
91
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Derivation of Equation 10.97 in Zettili: Quantization of the EM Field
I am reading through Zettili, and I am stuck on one of the steps that Zetilli makes when quantizing the EM field, specifically with page 567.
Zettili first introduces the Fourier series for the ...
0
votes
1
answer
31
views
What is the relation between the Faraday effect and the Zeeman effect?
The Faraday Effect basically says that certain materials under a magnetic field have different indexes of refraction for right and circular polarized light. Linear light which is a superposition of ...
0
votes
0
answers
46
views
A question on perturbed flux function
Given a magnetic field $\mathbf{B}=B_{0}\left(\dfrac{xz}{z_{s}^{2}},\dfrac{yz}{z_{s}^{2}}, 1-2\left( \dfrac{x^{2}}{r_{s}^{2}}+\dfrac{y^{2}}{r_{s}^{2}}\right) -\dfrac{z^{2}}{z_{s}^{2}}\right)$ with the ...
0
votes
0
answers
16
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Effects of Localized Medium Changes on Field Propagation
I've studied various theories related to fields. These theories often include equations describing how the activity of a source is transmitted to other locations. The properties of the medium ...
0
votes
0
answers
322
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Dipole moments of two level systems in radiation
Hi I am starting to learn about perturbation theory in quantum mechanics, and hence I am learning about oscillating radiation and it's effect on two-level systems. I just want to confirm that in this ...