Questions tagged [quantum-electrodynamics]
Quantum electrodynamics (QED) is the quantum field theory believed to describe electromagnetic interaction. It is the simplest example of a quantum gauge theory, where the gauge group is abelian, U(1).
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Does $\psi \bar\psi \to \psi \bar\psi$ have $s$-, $t$- and $u$-channels? [duplicate]
In Yukawa theory/QED, if we consider the scattering process between a fermion and an antifermion, am I right to think that we get a fermion and antifermion pair through $s$-channel, $t$-channel and $u$...
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Is $Z₀ = 120π$ ohm exact or approximate value for the vacuum impedance, and what determines the precise value?
The vacuum impedance is:
$Z₀ = √(μ₀/ε₀) =$ 376.730 ohm.
This is often approximated as 120π = 376.991 ohms in antenna engineering and electromagnetics textbooks.
The gap between these values is 0.069%.
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Evanescent Fields as a manifestation of interference effects
I have a question about evanescent fields. To summarize briefly the concept of evanescent fields: In classical electrodynamics when an EM wave passes from a dense medium into a thinner medium under ...
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Determining Feynman channels for electron-positron annihilation
I am currently taking AP physics 2. We have just reached our modern physics unit and as this is something that greatly interests me I wanted to look deeper into it. We were working on calculating ...
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Is it proven that different methods to compute cross-section in QED lead to the same answer?
Let us compute an arbitrary cross-section in QED using the on-shell prescription, but using different regularization methods (Pauli-Villars, dimensional regularization with different values of the ...
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Bare charge in dimensional regularization and on-shell renormalization
This question is a continuation of the previous one Question on dimensional regularization and on-shell renormalization
But it can be read independently.
As far as I understand, when one uses ...
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Question on dimensional regularization and on-shell renormalization
Trying to understand how the Dimensional Regularization works in combination with the on-shell renormalization scheme in QED, I think I got a conclusion (see Question 2 below) which I do not quite ...
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When is a theory effective?
I am currently studying $\chi PT$, which is an effective field theory for hadronic processes at low energies. This has made me wonder what it is that separates effective theories from fundamental ones....
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Dependence on renormalization parameter in computations with dimensional regularization
I am trying to better understand dimensional regularization. Computations using it are often performed with either the on-shell (OS) or the minimal subtraction (MS) renormalization prescription. In ...
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Understanding the relationship between wavelength and constructive interference distance in Cox and Forshaw's "clock" model
In Brian Cox and Jeff Forshaw's book The Quantum Universe, they introduce a pedagogical model where quantum particles are described by an array of "clocks" at each point in space. The length ...
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Axial anomaly using dimensional regularization
I am looking for papers or references where the axial (Adler–Bell–Jackiw) anomaly is computed explicitly using dimensional regularization by evaluating the triangle diagram.
Most treatments in ...
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Does the computational complexity of our physics equations affect the laws of physics? [closed]
Does the computational complexity of the math operations within our physics equations affect the physical system itself? This is an outlandish idea so I will start with a concrete example.
Suppose a ...
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How to understand the action of a stationary particle?
I am learning about action and how light takes all possible paths from point A to point B. How do we understand the action of a stationary particle like an electron? How do we understand the concept ...
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1-loop Vertex Correction in QED
Does anyone know of an article or textbook that contains a detailed calculation of the 1-loop vertex correction in QED using dimensional regularization? I mean a complete computation up to the ...
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What is the operator $\theta_r$ in Dirac's "The Quantum Theory of the Emission and Absorption of Radiation" paper?
In Dirac's "The Quantum Theory of the Emission and Absorption of Radiation" https://share.google/9SCmAJ0Han28kubNb. He talks about the energy and phase of an atomic system as "q-...
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