Quantum-ElectroDynamics (QED) is the quantum field theory believed to describe the electromagnetic interaction (and with some extension the weak nuclear force).
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Are electromagnetic “plane” waves measurable or just a virtual concept?
I find plane waves are uncompatible with light cone.
Perhaps plane waves are "virtual" and can never be measured
in that case, shouldn't we call plane waves as "virtual plane waves"?
(other option ...
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What is Electromagnetic Induced Transparency?
Please can anyone explain the concepts of electromagnetic induced transparency? I am having problem with the technicality of the explanation on wikipedia. Please I am an engineer with a physics ...
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Is it true that the angular momentum of electromagnetic waves in an anisotropic medium is an integral of motion?
Extending my previous question Angular moment and EM wave, does it make sense to talk about the angular momentum of electromagnetic waves in an anisotropic medium? It is not obvious that the angular ...
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critical electric field that spontaneously generates real pairs
With the current QED framework, If an electric field is strong enough (say, near a nucleus with $Z > 140$) , pair production will occur spontaneously? Is this a real effect or an artifact before ...
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What is the spectral energy density of virtual photons around a unit charge at rest?
Given that my previous question, namely "What is the number density of virtual photons around a unit charge?" has no precise answer, here is a more precise wording:
What is the virtual photon ...
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What is the density of virtual photons around a unit charge?
It seems that virtual photons also exist in vacuum. So the precise question is:
What is the additional virtual photon density due to the electric field of a unit charge?
Or: How many virtual photons ...
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What physics does occur at short distances in QED?
Let us take the standard QED ($e^-, e^+, \gamma$) as a model of QFT and ask what is its "short-distance" physics?
They say the UV infinities appear because we do not know the real physics of short ...
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Are virtual photons affected by effective gravity in non-linear quantum electrodynamics?
Quantum electrodynamics based upon Euler-Heisenberg or Born-Infeld Lagrangians predict photons to move according to an effective metric, which is dependent on the background electromagnetic field in a ...
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Why is the Gupta-Bleuler gauge unfashionable?
In the early days of quantum electrodynamics, the most popular gauge chosen was the Gupta-Bleuler gauge stating that for physical states,
$$\langle \chi | \partial^\mu A_\mu | \psi \rangle = 0.$$
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Why can't fermions be affected by effective gravity in non-linear quantum electrodynamics?
Quantum electrodynamics based upon Euler-Heisenberg or Born-Infeld Lagrangians predict photons
to move according to an effective metric which is dependent on the background electromagnetic
field. In ...
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Why can't photons have a mass
Why can't photons have a mass? Could you explain this to me in a short and mathematical way?
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How is the double slit experiment modeled in contemporary physical theories?
Suppose I have the following double split experiment set up:
a monochromatic electron source of low intensity, which we can model as emitting a single electron at a time with energy $T$.
a ...
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Virtual photon description of B and E fields
I continue to find it amazing that something as “bulky” and macroscopic as a static magnetic or electric field is actually a manifestation of virtual photons.
So putting on your QFT spectacles, look ...
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Virtual photon counting
How to calculate number of exchanged virtual pohotons per unit of time between two electromagnetically interacting objects?
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Properties of the photon: Electric and Magnetic field components
Consider an electromagnetic wave of frequency $\nu$ interacting with a stationary charge placed at point $x$. My question concerns the consistency of two equally valid quantum-mechanical descriptions ...
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How does charge work if photons are neutral?
How can an electron distinguish between another electron and a positron? They use photons as exchange particles and photons are neutral, so how does it know to repel or attract?
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How do electrons interact if one of them had just exited the two slits of the double-slit experiment?
Consider the following experiment: a double-slit set-up for firing electrons one at a time. Let's now add a second electron (orange), which is fired parallel to the first one, but in the opposite ...
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How to calculate the properties of Photon-Quasiparticles
in recent questions like "How are classical optics phenomena explained in QED (Snell's law)?" and "Do photons gain mass when they travel through glass?" we could learn something about effective ...
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How are classical optics phenomena explained in QED (color)?
How is the following classical optics phenomenon explained in quantum electrodynamics?
Color
According to Schroedinger's model of the atom, only particular colors are emitted depending on the type ...
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How are classical optics phenomena explained in QED (Snell's law)?
How is the following classical optics phenomenon explained in quantum electrodynamics?
Reflection and Refraction
Are they simply due to photons being absorbed and re-emitted? How do we get to ...
