Register to reply

U(1) Gauge symmetry

by dfttheory
Tags: gauge, symmetry, symmetry group, u(1)
Share this thread:
Nov8-13, 11:52 PM
P: 2
So, I have a basic/general question here. I understand that, for example, the QED Langrangian has U(1) gauge symmetry. I also understand that this means (when you have written the Lagrangian with the covariant derivative) that if you transform the wavefunction ([itex]\psi \rightarrow e^{i \theta (x)} \psi[/itex]) and the covariant derivative, this Lagrangian remains invariant.

What I don't understand is this: what does it mean for the wavefunction to have this local symmetry? How do we know that electrons / photons are described by this theory? What principal of nature says that the wavefunction has this symmetry?

I know this is three questions, but I am just trying to get a sense of what informs the choice of symmetry in these theories before I continue transforming and writing gauge invariant theories.

Thank you for any attention you may pay this question!
Phys.Org News Partner Physics news on
New complex oxides could advance memory devices
'Squid skin' metamaterials project yields vivid color display
Scientists control surface tension to manipulate liquid metals (w/ Video)
Nov8-13, 11:58 PM
P: 2
I just realized that the discussions related to this may contain some of what I am looking for. I would be interested in any additional discussion about this. Thanks!

Register to reply

Related Discussions
Gauge Symmetry in QM Quantum Physics 4
[Holography] Global symmetry in boundary corresponds to gauge symmetry in bulk? Beyond the Standard Model 14
Why are there several gauge fixing choice for gauge symmetry fields? Quantum Physics 3
Gauge symmetry High Energy, Nuclear, Particle Physics 10
Gauge symmetry and symmetry breaking High Energy, Nuclear, Particle Physics 2