Symmetry and Conservation of Charge

AI Thread Summary
The discussion centers on the relationship between symmetries and conservation laws, specifically focusing on the conservation of charge. It is established that conservation laws arise from underlying symmetries, with conservation of energy, linear momentum, and angular momentum linked to time and space symmetries. The conservation of charge is associated with global gauge symmetry, which is distinct from local gauge symmetry that varies with spatial coordinates. Participants clarify that both global and local gauge symmetries are recognized in physics, despite initial confusion regarding their definitions. The conversation highlights the nuanced understanding of gauge symmetries in the context of conservation laws.
Moridin
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I understand that all conservation laws have underlying symmetries and that all symmetries have corresponding conservation laws. From reading some popular science books (don't shoot me :P), I understand that conservation of energy, linear and angular momentum are a natural consequence of time translation symmetry, space translation symmetry and space rotation symmetry respectively.

What symmetry does the conservation of charge follow from?

Thank you for your time, have a nice day.
 
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Moridin said:
What symmetry does the conservation of charge follow from?
From global gauge symmetry
 
jdg812 said:
From global gauge symmetry

...isn't that a contradiction in terms? To "gauge" a symmetry means to make it local...
 
olgranpappy said:
...isn't that a contradiction in terms? To "gauge" a symmetry means to make it local...
No, global gauge symmetries are independent of space; local gauge symmetries depend on spatial coordinates. I might this wrong (it's been a while), but I seem to recall that gauge symmetries in general are symmetries of a potential field, such as the electric potential field, the derivatives of which give you the electric field.

EDIT: You know, as I stir up my old memories of this, I now seem to recall that people do use "gauge" to refer to local gauge symmetries, especially in gauge field theory. What is confusing me now is that global choices of gauge, like the Lorentz or Coulomb gauge in Classical E&M, also reflect a gauge symmetry.
 
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olgranpappy said:
...isn't that a contradiction in terms? To "gauge" a symmetry means to make it local...
Both of expressions "local gauge symmetry" and "global gauge symmetry" are generally accepted in physics.
 
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