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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$Z_1=Z_2$ and its relation to vertex renormalization in QED
I have been working on the full renormalization of scalar QED with self-interactions, following the steps of Schwartz’s treatment on spinor QED (Chap 19). I have 3 main questions regarding this:
Need ...
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Interferometer designed to create diffraction in free space
I designed the following interferometer:
If the light beam -theoretically- is very narrow , will light be diffracted away from point B from QED's perspective?
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Does one electron in superposition repel itself?
Consider Quantum Electrodynamics, and consider the electron field to be in a state which is a superposition of two wavepackets, each located in a different spatial position. Explicitly:
$$|\psi\rangle ...
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Elastic scattering and conservation of spin
I am trying to understand conservation of spin in QED elastic scattering in these nice notes (VJ Martin, Particle Physics, Spring 2012, University of Edinburgh): https://www2.ph.ed.ac.uk/~vjm/Lectures/...
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Scalar QED atoms - will they pass through each other?
Atoms generally do not pass through each other. This is usually attributed to the Pauli exclusion principal between the electrons (see links below).
If the electrons and nucleons were switched with ...
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Does QED explain why Moving charge produce magnetic field? [closed]
I wonder that moving charge produce magnetic fields. Now a days quantum field theory explain much of particle physics their underlying mediate particles.
But can QED explain why moving charge produce ...
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Destructive interference pattern perpendicular to photon's propagation direction
I'm studying the interference pattern for light. For example, the following is the interference pattern for double slit experiment:
I'm curious to know if there is an existing interference pattern ...
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QED: Structure of electron vertex function in the massless limit
I am working my way through Peskin & Schröder's "Introduction to QFT". In section 6.2, the formal structure of the electron vertex function $\Gamma^\mu$ is considered. From Lorentz ...
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Why is $F_1(0) = 1$? (form factor in QED)
In section 6.2 in Peskin and Schroeder (P&S) on vertex corrections, it is shown (eq 6.34) that the physical charge of the electron is given by $eF_1(0)$ (as shown by comparing the nonrelativistic ...
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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 ...
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Spinor-helicity formalism: relationship between 1 and 2 reference vector setups
The spinor-helicity formalism is usually set up so that for a massless vector boson (photon or gluon) with momentum $k$ an arbitrary reference momentum $p$ is introduced and the corresponding ...
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What is a correlation function of renormalized currents in QED?
The correlation function
$$
\langle\beta|\mathcal{T}J(x_1)\cdots J(x_n)|\alpha\rangle,\tag{1}
$$
where $J^\mu=e\bar{\psi}\gamma^\mu\psi$ is the QED current, is usually interpreted as the diagram of ...
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Can an electron be produced inside a proton?
We know that inside a proton there is a sea of quarks, antiquarks and gluons. This happens as the valence quarks emit gluons which then split into a quark-antiquark pairs. These pairs become gluons ...
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From a QED perspective, how is light created and propagated?
Using QED, what happens, exactly, when light is created?
Let's say an electron loses energy by dropping to a lower orbital, causing quantum of energy to be "emitted." What is that energy ...
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A question on IR divergence in Peskin-Schroeder chapter 6
In equation 6.64 of Peskin Schroeder, it computes $f_{\text{IR}}(q^2)$ in the limit $-q^2\to\infty$. Now, if we try to simplify the integral:
\begin{align}
f_{\text{IR}}(q^2) &=\int_0^1d\xi\;\frac{...
