Phil Lucht Math & Physics Archive
Home / Math and Physics Files / Physics / Quantum Mechanics / angmom_spin math stuff

rotation matrices

DOCX · 32.4 KB
Open DOCX file

Short Word note by Phil dated 1.23.08 collecting rotation matrix formulas. It covers the SU(2) two-dimensional case with generators J = σ/2 and R = exp(-iθ n·J) = cos(θ/2) - i σ·n sin(θ/2), then the SO(3) Cartesian case with generators (Ji)jk = -i εijk, the general axis-angle rotation matrix, a trace formula for Rij, and the relation to the Wigner D(1) matrices through a unitary change of basis. Many matrices were lost in text extraction.

AI-written summary; may contain errors. This description is approximate.

Extracted text (machine-read; may contain errors)
Rotation Matrices PhL 1.23.08 1. Two dimensions as in SU(2): generators: Ji = (1/2)i rotations: R() = exp(-iJ) Jx = (1/2) Jy = (1/2) Jz = (1/2) Rx = Ry = Rz = R() = exp(-iJ) = exp(-i/2σ) = cos(θ/2) – i σ sin(θ/2) since (σ)2 = 1 2. Three dimensions Cartesian as in SO(3): Jx = Jy = Jz = Rx() = Ry() = Rz() = (Ji)jk = -i ijk. [Ji, Vj ] = iijkVk R V R-1 = R-1 V Special case of the above: R J R-1 = R-1 J for any J representation [R()]kl = cos kl + ksl ns sin + nk nl (1 - cos) Rij = (1/2) tr [ iRjR†] Ry() = U d(1)() U-1 Rz() Ry() Rz() = U D(1)(,,) U-1 U = <k|1,m> = Ukm Transcription of the 3D rotation matrices: Rx(θ) = Ry(θ) = Rz(θ) = Here is a 2D Rz(θ) matrix Rz(θ) =