The physical meaning of a symmetry

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SUMMARY

The discussion centers on the physical meanings of symmetry groups in particle physics, specifically SU(2), SU(3), U(1), and O(3,1). SU(2) and SU(3) relate to the interchangeability of quarks and leptons, while U(1) is associated with the polarization of light, being isomorphic to SO(2), the 2D rotation group. The Lorentz group, identified as SO(3,1), describes the structure of space-time with a metric signature of +++- or ---+. The conversation also references Noether's Theorem, which connects symmetries to conservation laws in physics.

PREREQUISITES
  • Understanding of SU(2) and SU(3) symmetry groups in particle physics
  • Familiarity with U(1) and its relation to light polarization
  • Knowledge of the Lorentz group SO(3,1) and its significance in relativity
  • Awareness of Noether's Theorem and its implications for conservation laws
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  • Research the implications of Noether's Theorem in modern physics
  • Explore the mathematical structure of U(1) and its applications in quantum field theory
  • Study the properties and applications of the Lorentz group SO(3,1) in relativity
  • Investigate the role of symmetry in particle physics and its impact on conservation laws
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Physicists, particularly those specializing in particle physics and quantum field theory, as well as students and researchers interested in the foundational principles of symmetries in physics.

Planck const
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I know that the physical meaning of SU3 and SU2 - you can change the places of the quarks or/and leptons and you will get the same results.

What is the physical meaning of U1, and O3,1 (Lorentz group if I am not wrong)?

I know U1 is connect with the Polarization of the light.

Thanks very much to the people who will answer... (sorry about my bad english)
 
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It seems many of the laws of physics originate in symmetries.

You might find Nother's Theorem of interest:

http://en.wikipedia.org/wiki/Nöther's_theorem

where different symmetries are shown to underly different conservation "laws".
 
U(1) is isomorphic to SO(2), the 2D rotation group.

The connection with the polarization of light is that the polarization of massless fields in n space-time dimensions lives in the (n-2) transverse dimensions, in this case, 2. So the transverse-dimension rotation group in 4D is SO(2).

The Lorentz group is indeed SO(3,1) -- the numbers are because the space-time metric's signature is +++- or ---+, depending on the convention.
 

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