All Questions
Tagged with quantum-electrodynamics quantum-optics
89
questions
3
votes
2
answers
106
views
Parametric down-conversion - QFT necessary?
In quantum optics, one ususally starts by quantizing the free electric field and obtains an expression for the electric field operators:
$$ E(\vec{r},t) = \sum_{\vec{k},p} C_{\vec{k}} \vec{e}_{\vec{k},...
- 31
4
votes
1
answer
86
views
What happens if obstacles (walls) been put where destructive interference occurs in double slit experiment?
If photon doesn't have probability to be in dark (destructive interference) area, what will be the effect of adding obstacles (walls) in the dark (destructive interference) area for the double slit ...
- 81
1
vote
1
answer
86
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Is the annihilation operator an observable (it is non-Hermitian)?
In most treatments of quantum mechanics that I have seen, observables of a quantum system are defined using Hermitian operators. The most intuitive reason for this is that Hermitian operators have ...
- 11
0
votes
1
answer
88
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What is the observable for the optical field?
Typically, observables in quantum mechanics are associated with Hermitian operators. However, Glauber argues in 1963 ([1]) that the electric field operator $\hat{\mathbf{E}}(x,t)$ is not the relevant ...
- 11
3
votes
1
answer
55
views
Renormalisation in quantum optics
When reading about QED in QFT books, renormalisation seems to be essential to get results eventually. It also seems absolutely necessary even for low energies, since the internal lines lead to ...
- 1,831
0
votes
1
answer
56
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How to distinguish a doppler-shifted photon from a non-doppler-shifted photon of the same frequency?
Can one physically distinguish a photon of frequency $\omega$, generated by a stationary laser, from a photon generated by a mechanically moving laser (a different laser from the first one) which, due ...
- 342
1
vote
2
answers
78
views
Tightly-focusing a single photon
I'm curious about the feasibility, both theoretically and experimentally, of tightly focusing (or spatially trapping) a single photon to guarantee its precise targeting. If it’s possible, isn’t it ...
- 342
1
vote
2
answers
53
views
The relative phase of photons in two-photon absorption
In two-photon absorption (TPA), the relative polarization of the two photons about to be absorbed simultaneously by an atom is crucial in determining the TPA rate. However, there is a lack of ...
- 342
1
vote
0
answers
47
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Unit polarization vectors in the vector potential for the quantization of the free electromagnetic field
I am studying the quantization of free electromagnetic field using the book "Optical Coherence and Quantum Optics" by Mandel and Wolf (Mandel&Wolf, Chapter 10) and when I started to ...
0
votes
0
answers
22
views
Field theory behind dipole traps / optical tweezers
I'm trying to re-construct an explain for how an optical tweezer traps a neutral atom with a non-zero dipole.
It began something like this:
"The vacuum is filed with short-lived dipoles form by ...
- 21
2
votes
0
answers
55
views
Why does the spontaneous emission rate scale with energy?
Good afternoon,
the standard description of spontaneous emission in quantum optics is - to my knowledge - via coupling of an excited atom to vacuum modes of the em-field, which are still occupied at $...
- 21
0
votes
0
answers
38
views
Microscopic explanation of electromagnetic wave interacting with electron (medium) leading to decrease of light speed
Electromagnetic waves decrease in speed when propagating through a medium. The commonly accepted microscopic explanation is that photons are absorbed by electrons and then re-emitted, resulting in a ...
- 59
0
votes
0
answers
49
views
Derivation for Quantum optics dipole radiation formula
An often used formula for the radiation field of a dipole is the following one:
\begin{align}
\vec{E}(t, \vec{x}) = \frac{1}{4 \pi x^3} ( 3 \hat{x} [ \hat{x} \vec{d}(t_r)] - \vec{d}(t_r) ) + \frac{1}{...
- 6,773
3
votes
0
answers
58
views
Quantization of electrodynamics in a nonlinear dielectric medium
Recently I read this paper https://doi.org/10.1103/PhysRevA.30.1860 by Hillery and Mlodinow about the (canonical) quantization of electrodynamics in nonlinear dielectric media. They assume that the ...
- 587
0
votes
1
answer
61
views
Description of AMO interactions in terms of QED Lagrangian
I consistently had this question of how could the light-matter interaction be described in terms of the fundamental language of QED. To be more specific, is there a way to 'derive' the interaction ...
- 57