Timeline for Gauge invariance in QED
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 19, 2022 at 19:26 | vote | accept | MsTais | ||
| Sep 8, 2016 at 8:37 | comment | added | Statics | The gauge symmetry does not describe anything physical, since it does not change the physics for different gauge group parameters $\alpha$. The electrodynamical $A_\mu$ does not describe the full picture correctly since the description is on the classical level. In order to account for the quantum nature of the particles the description needs to be quantized. One can view the imposing of gauge invariance as a trick to obtain the desired conserved quantities. Nevertheless it remains a very efficient way to describe the nature of QED. | |
| Sep 7, 2016 at 20:20 | comment | added | MsTais | Symmetry of mathematica expressions comes from physical symmetries, symmetries in parameter space, etc. They don't just show up typically. The reason of me doubting that is the same as always: the fact that we don't see something happening is not the proof that it doesn't happen. I find the fact that $A^{\mu}$ coming out from electrodynamics and naturally living in 4D, and yet not describing the photon correctly without some tricks, a great irritation=( If something fundamental is not general, it very much might be false. | |
| Sep 7, 2016 at 13:56 | comment | added | Statics | Gauge invariance hides the true number of degrees of freedom and leads to a redundancy in the physical description. Therefore it is more of a symmetry of the mathematical expressions, not that much of a physical symmetry... QFT is able to describe the nature with 2-dof-photons quite well. What would be the reason to assume there are other dof's? | |
| Sep 7, 2016 at 13:25 | comment | added | MsTais | Why do we think that photons have 2 dof? Experiment? What if there is more, but we just don't have tools to register them? And it somehow magically linked to zero mass... Usually the reason for imposing constrains in QM and QFT is symmetries. Gauge invariance is not a symmetry in real (3+1)D space, but some kind of symmetry in parameter space, which I don't understand, cannot imagine. | |
| Sep 5, 2016 at 9:42 | history | answered | Statics | CC BY-SA 3.0 |