Questions tagged [gauge]

Use this tag to discuss gauge-fixing conditions, as in the phrase 'choosing a gauge', such as, e.g. the Lorenz gauge, Coulomb gauge, Feynman gauge, Landau gauge, axial gauge, temporal gauge, light cone gauge, etc.

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Nickel gauge factor and why is it so quirky?

Hi so I've been researching the piezo-resistance effect and experimenting with finding different metals' gauge factors by applying stress on a wire and measuring the change in resistance however I can'...
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Gauge anomalies?

Why are gauge anomalies so important for any model? Secondly, any model has to respect the gauge anomalies cancellation requirement? If this isn't true, then why does one check their model to look ...
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Does $\xi$ invariance in $R_\xi$ gauges imply gauge invariance?

Often in QFT calculations, a $R_\xi$ gauge fixing term $$\mathcal{L}_{GF} = \frac{1}{2\xi}(\partial_\mu A^\mu)$$ is used, with $\xi$ left arbitrary. Any gauge invariant quantity must then be $\xi$ ...
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The choice of gauge seems has contradiction

Suppose I have a quantum object, inside it the electric field distribution is $\vec{E}(\vec{r})$, with this field we can obtain the scalar potential $\phi(\vec{r})$, a charged particle in this object ...
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Existence of the Coulomb gauge

In reading about the Coulomb gauge, my mind seems to have painted itself into a corner. For, lets assume that Maxwells equations for the physics of the problem are solved by the magnetic vector ...
2 votes
1 answer
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Do the retarded potentials satisfy the Lorenz Gauge condition?

Every source I have ever seen derives the retarded and advanced potentials by finding the Green's functions of the inhomogeneous Lorenz gauge conditions, and I have always thought that any linear ...
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Calculating the electric potential in the Lorenz gauge

It has been a while since I have done any electromagnetism, and at one point I knew how to do this but for the life of me can't figure this out. The problem is as follows, if we have a time dependent ...
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The $D_{00}$ component of the photon propagator in the Feynman and Coulomb gauges

I am trying to understand some derivations involving the photon propagator, and I am having a lot of trouble with expressions in different gauges and also with terminology in general. Here is what I ...
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1 answer
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Local order parameter for confinement in gauge theories

I would like some help clarifying what Zinn Justin is saying in his book "Quantum Field Theory and Critical Phenomena" p.805 on detecting confinement of gauge theories. In particular, I ...
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Gauge invariant Green's function for a point particle

This question is a follow up to the question (Gauge invariant Green's function for electrodynamics). It is not possible to generally solve the eqution \square A^{\mu}-\partial^{\...
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Limitations of describing QED interactions in the Coulomb gauge?

When we work with the S-matrix operator to describe interactions between the quantized Maxwell field and a classical source or a Dirac field, are there any limitations one needs to keep in mind when ...
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Gauge dependence of Feynman propagator

In QED we have the property that any gauge dependence must cancel out in physical quantities. Nevertheless Feynman rules display some gauge dependence. This is what I am a little unclear on. The ...