Transforming Representations of SO(3) to Act on Vectors?

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    Representations So(3)
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Discussion Overview

The discussion revolves around the representation of the special orthogonal group SO(3) and its application to quantum field theory (QFT), particularly in relation to how elements of SO(3) can act on vectors versus spinors. Participants explore the nature of representations, the relationship between different types of representations, and the implications for transformations in quantum mechanics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant seeks clarification on how to obtain a representation of SO(3) that acts on vectors, as opposed to spinors, using generators from the Lie algebra.
  • Another participant suggests using the adjoint representation defined by the commutation relations of the Pauli matrices to construct a 3x3 matrix representation.
  • It is noted that SO(3) does not have a 3-spinor representation, which may lead to confusion regarding the nature of the representations.
  • A participant explains that SO(3) has various representations, including scalar, spinor, and vector representations, and describes the characteristics of these representations.
  • One participant provides specific examples of 3x3 matrices that can serve as generators for SO(3) and asserts that these matrices yield the usual rotation matrices for 3-vectors upon exponentiation.
  • Another participant mentions the distinction between the complex vector space representation for spin-1 and the real vector space representation for vectors, suggesting they may be unitarily equivalent.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between representations of SO(3) and their applicability to vectors versus spinors. There is no consensus on the precise nature of these representations or their implications for quantum mechanics.

Contextual Notes

Some participants highlight the complexity of the topic, suggesting that the discussion may benefit from additional resources or texts on group theory and quantum mechanics. There are also indications of potential confusion regarding the definitions and properties of different representations.

Who May Find This Useful

This discussion may be of interest to students and researchers in quantum field theory, representation theory, and those exploring the mathematical foundations of physics, particularly in the context of particle physics and symmetries.

  • #31
dextercioby said:
The truth is that you really need to read mathematics, because explaining the facts without understanding them right now won't help you too much.

The bolded part is incorrect.

I'm not really up to reccomendations to the elementary stuff, i.e. learning something from beginning. I really hate introductory texts and especially on the mathematics behind the physical theory.

I guess saying that:" SU(2) is the double cover of SO(3), and SU(2) is isomorphic to the coset SO(3)/Z2." would have been the right statement although I am not sure what a double cover is.

Introductory texts are the basis, how then would one learn stuff? If not by some "introductory" text that relates to more pedestrian stuff?

Honestly, I do not hate introductory texts about the mathematics of a physical theory, those are the tools one needs to handle the model.. And at the end I want to calculate stuff and get results not just understand some axioms and be happy with it..
 

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