SU(3), U(1), O(3), etc what are they?

  • Thread starter cefarix
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In summary, the conversation discusses the concept of "Lie Groups," specifically examples of U(1), SU(2), and SU(3). These groups have different applications in physics, with U(1) corresponding to the photon, SU(2) to W's and Z's, and SU(3) to gluons. The conversation also briefly mentions O(3), which is the orthogonal group of order 3. Additional information and definitions of these groups can be found at the provided links.
  • #1
cefarix
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I've heard them used before...some sort of symmetry, but I never figured out what it really is. Can someone please explain the concepts to me? thx
 
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  • #3
SU(3) is the "special unitary group of order 3": 3 by 3 complex matrices with determinant 1

O(3) is the "orthogonal group of order 3": 3 by 3 real matrices with determinant 1 or -1

U(1) is a bit puzzling! I would interpret U(n) as the "unitary group of order 3": n by n complex matrices with determinant 1 or -1. But "1 by 1 matrices" are just numbers. I guess U(1) would be the multiplicative group with members 1, -1, i, and -i!
 
  • #4
You will here them used to describe different types of standard model features.

U(1) corresponds to photon
SU(2) to W's and Z's
SU(3) to the gluons.
 

FAQ: SU(3), U(1), O(3), etc what are they?

1. What is SU(3)?

SU(3) is a mathematical group that represents the symmetries of a system with three dimensions. It is often used in the study of quantum mechanics and particle physics.

2. What is U(1)?

U(1) is another mathematical group that represents the symmetries of a system with one dimension. It is commonly used in the study of electromagnetism and gauge theories.

3. What is O(3)?

O(3) is a mathematical group that represents the rotations and reflections of a three-dimensional object. It is often used in geometry, physics, and computer graphics.

4. How do SU(3), U(1), and O(3) relate to each other?

SU(3), U(1), and O(3) are all examples of Lie groups, which are mathematical structures used to describe symmetries. While they are each unique groups, they can be related through the concept of symmetry breaking, where a larger symmetry is broken down into smaller symmetries.

5. What applications do SU(3), U(1), and O(3) have in science?

SU(3) and U(1) are fundamental to the Standard Model of particle physics, which describes the interactions of subatomic particles. O(3) is used in a variety of fields, including crystallography, molecular biology, and computer graphics. In general, these mathematical groups have wide-ranging applications in physics, chemistry, and other sciences that study symmetries and transformations.

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