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What is U(1) and SU(2) local gauge symmetry?
How are U(1) and SU(2) different from each other?
U(1) is a one-dimensional Lie group, while SU(2) is a three-dimensional Lie group. This means that the mathematical structures underlying these two symmetries are different. U(1) is also known as the Abelian group, while SU(2) is non-Abelian.