Rotation Group
Quantum Mechanics · Part 5
227 KB10 sections4 key equationsLaTeX typeset
Table of Contents
- 1.Rotation Group SO(3)
- 2.Lie Algebra so(3)
- 3.SU(2) Group
- 4.Lie Algebra su(2)
- 5.The 2-to-1 Homomorphism
- 6.Spin-1/2 and Spinors
- 7.Representations
- 8.Wigner D-Matrices
- 9.Physical Implications
- 10.Why Nature Uses SU(2), Not SO(3)
Key Equations
$$\text{SO}(3) = \{R \in \mathbb{R}^{3\times 3} : R^T R = \mathbb{I}, \det R = 1\}$$
$$[L_i, L_j] = i\epsilon_{ijk} L_k$$
$$J_1 = \frac{1}{2}\begin{pmatrix} 0 & 1 \\ 1 & 0 \end{pmatrix}, \quad J_2 = \frac{1}{2}\begin{pmatrix} 0 & -i \\ i & 0 \end{pmatrix}, \quad J_3 = \frac{1}{2}\begin{pmatrix} 1 & 0 \\ 0 & -1 \end{pmatrix}$$
$$\text{SU}(2) / \mathbb{Z}_2 \cong \text{SO}(3)$$
Equations are rendered with MathJax in the PDF with professional LaTeX typesetting.
Course Context
This PDF is part of the Quantum Mechanics course on CoursesHub.World. Master quantum mechanics from mathematical foundations to advanced topics. Covers Hilbert spaces, wave functions, angular momentum, perturbation theory, scattering, and path integrals with 450+ pages ...