Group Theory in Quantum Mechanics
Spring 2015 PHYS-5093

2015 Detailed List of Lecture Topics  

Lecture 1. Introduction to quantum amplitudes and analyzers (1.13.15)  View on YouTube

(Quantum Theory for Computer Age {QTCA} - Ch. 1 of Unit 1)

(Principles of Symmetry, Dynamics, and Spectroscopy {PSDS} - Sec. 1-2 of Ch. 1)


Beam Sorters


2-State Sorters: spin-1/2 vs. optical polarization

Geometry of optical polarization selection and Brewster’s angle

Feynman’s lever


Beam Sorters in Series and Transformation Matrices

Introducing Dirac bra-ket notation


“Abstraction” of bra and ket vectors from a Transformation Matrix

Introducing scalar and matrix products


Textbooks (Online!)

Link → Quantum Theory for the Computer Age URL is http://www.uark.edu/ua/modphys/markup/QTCAWeb.html
Link → Principles of Symmetry, Dynamics, and Spectroscopy URL is http://www.uark.edu/ua/modphys/markup/PSDSWeb.html

Lecture 2. Quantum amplitudes, analyzers, and axioms (1.15.15)  View on YouTube

(Quantum Theory for Computer Age - Ch. 1 of Unit 1 )

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 1-2 of Ch. 1 )


Review:“Abstraction” of bra and ket vectors from a Transformation Matrix

Introducing scalar and matrix products


Planck's energy and N-quanta (Cavity/Beam wave mode)

Did Max Planck Goof? What’s 1-photon worth?

Feynman amplitude axiom 1


What comes out of a beam sorter channel or branch-b?

Sample calculations

Feynman amplitude axioms 2-3


Beam analyzers: Sorter-unsorters

The “Do-Nothing” analyzer

Feynman amplitude axiom 4

Some “Do-Something” analyzers

Sorter-counter, Filter, 1/2-wave plate, 1/4-wave plate


From the Quantum Theory in the Computer Age:

Link → http://www.uark.edu/ua/modphys/pdfs/QTCA_Pdfs/QTCA_Text_2013/QTCA_Unit_1_Ch._1_2013.pdf
Link → http://www.uark.edu/ua/modphys/pdfs/QTCA_Pdfs/QTCA_Text_2013/QTCA_Unit_7_Ch._22_2005.pdf


See also the 2005 Pirelli Challenge site:

Link → http://www.uark.edu/ua/pirelli/php/light_energy_flux_1.php
Link → http://www.uark.edu/ua/pirelli/php/amplitude_probability_1.php

Lecture 3. Quantum amplitudes, analyzers, and axioms (1.20.15)  View on YouTube

(Quantum Theory for Computer Age - Ch. 1-2 of Unit 1 )

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 1-3 of Ch. 1 )


Review: Axioms 1-4 and“Do-Nothing”vs“ Do-Something” analyzers


Abstraction of Axiom-4 to define projection and unitary operators

Projection operators and resolution of identity


Unitary operators and matrices that do something (or “nothing”)

Diagonal unitary operators

Non-diagonal unitary operators and -conjugation relations

Non-diagonal projection operators and Kronecker ⊗-products

Axiom-4 similarity transformation


Matrix representation of beam analyzers

Non-unitary “killer” devices: Sorter-counter, filter

Unitary “non-killer” devices: 1/2-wave plate, 1/4-wave plate


How analyzers “peek” and how that changes outcomes

Peeking polarizers and coherence loss

Classical Bayesian probability vs. Quantum probability


Feynman 〈j⏐k〉-axioms compared to Group axioms

Lecture 4. Matrix Eigensolutions and Spectral Decompositions (1.22.15)  View on YouTube

(Quantum Theory for Computer Age - Ch. 3 of Unit 1 )

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 1-3 of Ch. 1 )


Unitary operators and matrices that change state vectors

... and eigenstates (“ownstates) that are mostly immune


Geometric visualization of real symmetric matrices and eigenvectors

Circle-to-ellipse mapping (and I’m Ba-aaack!)

Ellipse-to-ellipse mapping (Normal space vs. tangent space)

Eigensolutions as stationary extreme-values (Lagrange λ-multipliers)


Matrix-algebraic eigensolutions with example M = Matrix

Secular equation

Hamilton-Cayley equation and projectors

Idempotent projectors (how eigenvalues⇒eigenvectors)

Operator orthonormality and completeness


Spectral Decompositions

Functional spectral decomposition

Orthonormality vs. Completeness vis-a`-vis Operator vs. State

Lagrange functional interpolation formula

Proof that completeness relation is “Truer-than-true”


Diagonalizing Transformations (D-Ttran) from projectors

Eigensolutions for active analyzers

Lecture 5. Spectral Decomposition with Repeated Eigenvalues (1.27.15)  View on YouTube

(Quantum Theory for Computer Age - Ch. 3 of Unit 1)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 1-3 of Ch. 1)


Review: matrix eigenstates (“ownstates) and Idempotent projectors (Non-degeneracy case)

Operator orthonormality, completeness, and spectral decomposition(Non-degenerate e-values)

(Preparing for: Degenerate eigenvalues)


Eigensolutions with degenerate eigenvalues (Possible?... or not?)

Secular → Hamilton-Cayley → Minimal equations

Diagonalizability criterion


Nilpotents and “Bad degeneracy” examples: B = Matrix, and: N = Matrix

Applications of Nilpotent operators later on


Idempotents and “Good degeneracy” example: G = Matrix

Secular equation by minor expansion

Example of minimal equation projection


Orthonormalization of degenerate eigensolutions

Projection Pj-matrix anatomy (Gramian matrices)

Gram-Schmidt procedure


Orthonormalization of commuting eigensolutions. Examples: G = Matrix and: H = Matrix

The old "1 = 1∙1 trick" - Spectral decomposition by projector splitting

Irreducible projectors and representations (Trace checks)

Minimal equation for projector P = P2

How symmetry groups become eigen-solvers

Lecture 6. Spectral Decomposition of Bi-Cyclic (C2 ⊂ U(2)) Operators (1.29.15)  View on YouTube

(Quantum Theory for Computer Age - Ch. 7-9 of Unit 3)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 1-3 of Ch. 2)


Review:How symmetry groups become eigen-solvers


How C2 (Bilateral σB reflection) symmetry is eigen-solver


C2 Symmetric two-dimensional harmonic oscillators (2DHO)

C2 (Bilateral σB reflection) symmetry conditions:

Minimal equation of σB and spectral decomposition of C2(σB)


C2 Symmetric 2DHO eigensolutions

C2 Mode phase character table

C2 Symmetric 2DHO uncoupling and mixed mode projector algebra

2D-HO beats and mixed mode geometry


Three famous 2-state systems and two-complex-component coordinates


ANALOGY: U(2) vs R(3): 2-State Schrodinger: iħ∂t|Ψ(t)〉= H|Ψ(t)〉 vs. Classical 2D-HO: ∂2tx=-K•x

Hamilton-Pauli spinor symmetry ( σ-expansion in ABCD-Types) H = ωμσμ

Lecture 7. Spectral Analysis of U(2) Operators (2.3.15)  View on YouTube

(Quantum Theory for Computer Age - Ch. 10 of Unit 3)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 1-3 of Ch. 5)


Review of Lecture 6: 2 symmetry is 2D oscillators and three famous 2-state systems

Review of Lecture 6: 2-State Schrodinger: iħ∂t|Ψ(t)〉= H|Ψ(t)〉 vs. Classical 2D-HO: ∂2tx=-K•x

Review of Lecture 6: Hamilton-Pauli spinor symmetry ( σ-expansion in ABCD-Types) H = ωμσμ


Derive σ-exponential time evolution (or revolution) operator U = e-iHt = e-iσµωµt

Spinor arithmetic like complex arithmetic

Spinor vector algebra like complex vector algebra

Spinor exponentials like complex exponentials (“Crazy-Thing”-Theorem)


Geometry of U(2) evolution (or R(3) revolution) operator U = e-iHt = e-iσμωμt

The “mysterious” factors of 2 (or 1/2): 2D Spinor vs 3D Spin Vector space

2D Spinor vs 3D vector rotation

NMR Hamiltonian: 3D Spin Moment m in B field

Euler’s state definition using rotations R(α,0,0), R(0,β,0), and R(0,0,γ)

Spin-1 (3D-real vector) case

Spin-1/2 (2D-complex spinor) case


3D-real Stokes Vector defines 2D-HO polarization ellipses and spinor states

Asymmetry SA = SZ, Balance SB = SX, and Chirality SC = SY

Polarization ellipse and spinor state dynamics

Lecture 8. Group Theory in Quantum Mechanics (2.5.15)  View on YouTube

(Quantum Theory for Computer Age - Ch. 10A-B of Unit 3)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 1-3 of Ch. 5)


Review: How the “Crazy-Thing”-Theorem makes spinor and vector representation matrices

Half-angle Θ/2 = ϕ replacement and Darboux crank axis operators


Operator-on-Operator transformations


Product algebra for Pauli's σμ and Hamilton's qμ = -iσμ

Group product algebra

Jordan-Pauli identity and U(2) product R[Θ]R[Θ′]=R[Θ′′′] - formula

Transformation R[Θ]σμR[Θ] of spinor σμ-operators

Transformation R[Θ]R[Θ′]R[Θ] of group-operators

Operator-on-Operator transformations


Geometry of groups: Hamilton’s turns and It’s all done with mirrors!

Group product geometry

U(2) product R[Θ]R[Θ′] - geometry

Transformation R[Θ]R[Θ′]R[Θ] geometry


Euler R(αβγ) versus Darboux R[ϕϑΘ]

Euler R(αβγ) related to Darboux R[ϕϑΘ]

Euler R(αβγ) rotation Θ =0-4π-sequence [ϕϑ] fixed

R(3)-U(2) slide rule for converting R(αβγ)R[ϕϑΘ]

Euler R(αβγ) Sundial

Lecture 9. Applications of U(2) and R(3) representations I. (2.10.15)

(Quantum Theory for Computer Age - Ch. 10A-B of Unit 3)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 1-3 of Ch. 5 and Ch. 7)


Review: Fundamental Euler R(αβγ) and Darboux R[ϕϑΘ] representations of U(2) and R(3)

Euler R(αβγ) derived from Darboux R[ϕϑΘ] and vice versa

Euler R(αβγ) rotation Θ =0-4π-sequence [ϕϑ] fixed (and “real-world” applications)

R(3)-U(2) slide rule for converting R(αβγ)R[ϕϑΘ] and Sundial


Lecture 10. Applications of U(2) and R(3) representations II. (2.12.15)  View on YouTube

(Quantum Theory for Computer Age - Ch. 10A-B of Unit 3)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 1-3 of Ch. 5 and Ch. 7)


Review: Fundamental Euler R(αβγ) and Darboux R[ϕϑΘ] representations of U(2) and R(3)

Euler R(αβγ) derived from Darboux R[ϕϑΘ] and vice versa

Euler R(αβγ) rotation Θ =0-4π-sequence [ϕϑ] fixed (and “real-world” applications)


U(2) density operator approach to symmetry dynamics

Bloch equation for density operator

Quick U(2) way to find eigen-solutions for 2-by-2 H


The ABC’s of U(2) dynamics-Archetypes

Asymmetric-Diagonal A-Type motion

Bilateral-Balanced B-Type motion

Circular-Coriolis… C-Type motion


The ABC’s of U(2) dynamics-Mixed modes

AB-Type motion and Wigner’s Avoided-Symmetry-Crossings

ABC-Type elliptical polarized motion


Ellipsometry using U(2) symmetry coordinates

Conventional amp-phase ellipse coordinates

Euler Angle (αβγ) ellipse coordinates

Lecture 11. Representations of cyclic groups C3 ⊂ C6 ⊃ C2 (2.20.15)  View on YouTube

(Quantum Theory for Computer Age - Ch. 6-9 of Unit 3)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 3-7 of Ch. 2)



Review of C2 spectral resolution for 2D oscillator (Lecture 6 : p. 11, p. 17, and p. 11)


C3 gg-product-table and basic group representation theory

C3 H-and-rp-matrix representations and conjugation symmetry


C3 Spectral resolution: 3rd roots of unity and ortho-completeness relations

C3 character table and modular labeling


Ortho-completeness inversion for operators and states

Comparing wave function operator algebra to bra-ket algebra

Modular quantum number arithmetic

C3-group jargon and structure of various tables


C3 Eigenvalues and wave dispersion functions

Standing waves vs Moving waves


C6 Spectral resolution: 6th roots of unity and higher

Complete sets of coupling parameters and Fourier dispersion

Gauge shifts due to complex coupling


Introduction to CN beat dynamics and “Revivals” in Lecture 12


Web apps used:

Link → WaveIt
Link → MolVibes

Lecture 12. Symmetry and Dynamics of CN cyclic systems I. (2.20.15)  View on YouTube

(Geometry of U(2) characters - Ch. 6-9 of Unit 3)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 3-7 of Ch. 2)



C6 Spectral resolution: 6th roots of unity and higher

Complete sets of coupling parameters and Fourier dispersion

Gauge shifts due to complex coupling


Introduction to wave dynamics of phase, mean phase, and group velocity

Expo-Cosine identity

Relating space-time and per-space-time

Wave coordinates

Pulse-waves (PW) vs Continuous -waves (CW)

Wave coordinates for Linear Dispersion

Wave coordinates for Bohr-Schrodinger Dispersion

Einstein-L orentz-Minkowski laser coordinates

Lecture 12.5 Symmetry and Dynamics of CN cyclic systems II. (2.24.15)  View on YouTube

(Geometry of U(2) characters - Ch. 6-9 of Unit 3)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 3-7 of Ch. 2)



Wave coordinates in spacetime and per-spacetime for Bohr-Schrodinger Dispersion

Phase velocity for simple wave ei(kx-ωt): Newton’s “corpuscle” tracks vs. wave-zero paths

Slow L-wave eiL=ei(k(L)·x-ω(L)·t)

Fast R-wave eiR=ei(k(R)·x-ω(R)·t)

Phase velocity for wave pair eiL +eiR=S·D: Half-sum factor S=ei(L+R)/2

Group velocity for wave pair eiL +eiR=S·D: Half-difference factor D=ei(L-R)/2+e-i(L-R)/2


Introduction to wave coordinates by Left-moving and Right-moving laser beams

L-laser 600THz and R-laser 600THZ (Laser lab frame)

Phase P-vector and group G-vector span Cartesian spacetime coordinates

L′-laser 300THz and R′-laser 1200THZ (Doppler shifted in moving frame)

Doppler shifted L′-vector and R′-vector in (L, R)-per-spacetime

Vectors of phase P′=(R′+L′)/2 and group G′=(R′-L′)/2

Einstein-Lorentz-Minkowski “Relawavity” spacetime coordinates

Brief tour of and relativistic mechanics by geometry

Summary of optical wave parameters for relativity and QM

Lecture 12.6 Symmetry and Dynamics of CN cyclic systems III. (3.3.15)

(Geometry of U(2) characters - Ch. 6-9 of Unit 3)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 3-7 of Ch. 2)



Two wave archetypes: Pulse-Wave (PW) versus Continuous-Wave (CW)

Comparing spacetime uncertainty (Δx or Δt) with per-spacetime bandwidth (Δκ or Δυ)

Introduction to beat dynamics and “Revivals” due to Bohr-dispersion

Relating ∞-Square-well waves to Bohr rotor waves

∞-Square-well wave dynamics

SinNx/x wavepacket bandwidth and uncertainty

∞-Square-well revivals: SinNx/x packet explodes! (and then UNexplodes!)

Bohr-rotor wave dynamics

Gaussian wave-packet bandwidth and uncertainty

Gaussian Bohr-rotor revivals and quantum fractals

Understanding fractals using geometry of fractions (Rationalizing rationals)

Farey-Sums and Ford-products

Discrete CN beat phase dynamics (Characters gone wild!)

The classical bouncing-ball Monster-Mash

Polygonal geometry of U(2) ⊃ CN character spectral function

Algebra

Geometry

Lecture 13 CN symmetry systems coupled, uncoupled, and re-coupled (3.5.15)  View on YouTube

(Geometry of U(2) characters - Ch. 6-12 of Unit 3)

(Principles of Symmetry, Dynamics, and Spectroscopy - Sec. 1-12 of Ch. 2)



Breaking N cyclic coupling into linear chains

Review of 1D-Bohr-ring related to infinite square well (and review of revival)

∞-Square well paths analyzed using Bohr rotor paths

Breaking C2N+2 to approximate linear N-chain

Band-It simulation: Intro to scattering approach to quantum symmetry


Breaking C2N cyclic coupling down to CN symmetry

Acoustical modes vs. Optical modes

Intro to other examples of band theory

Type-AB avoided crossing view of band-gaps


Finally! Symmetry groups that are not just CN

The “4-Group(s)” D2 and C2v

Spectral decomposition of D2

Some D2 modes

Outer product properties and the Crystal-Point Group Zoo

Lecture 14 Smallest non-Abelian group D3 (and isomorphic C3v ~D3) (3.10.15)  View on YouTube

(QTCA Unit 5 Ch. 15; Int.J.Mol.Sci, 14, 714(2013) p.755-774)

(PSDS - Ch. 3)



3-Dihedral-axes group D3 vs. 3-Vertical-mirror-plane group C3v

D3 and C3v are isomorphic (D3 ~ C3v share product table)

Deriving D ~ C products:

By group definition ⏐g〉=g⏐1〉 of position ket ⏐g〉

By nomograms based on U(2) Hamilton-turns

Deriving D3 ~ C3v equivalence transformations and classes


Non-commutative symmetry expansion and Global-Local solution

Global vs Local symmetry and Mock-Mach principle

Global vs Local matrix duality for D3

Global vs Local symmetry expansion of D3 Hamiltonian


1st-Stage spectral decomposition of global/local D Hamiltonian E operators)

Group theory of equivalence transformations and classes

Lagrange theorems

All-commuting operators and D3-invariant class algebra (center)

All-commuting projectors and D3-invariant characters

Group invariant numbers: Centrum, Rank, and Order


Spectral resolution to irreducible representations (or “irreps”) foretold by characters or traces

Crystal-field splitting: O(3) ⊃ D3 symmetry reduction and D↓ D3 splitting


Lecture 15 Spectral decomposition of groups D3 ~ C3v (3.12.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774; QTCA Unit 5 Ch. 15)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 3)



Review: 1st-Stage Spectral resolution of D3 Center (Class algebra)

Group theory of equivalence transformations and classes

Lagrange theorems

All-commuting class projectors


D3-invariant character ortho-completeness

Spectral resolution to irreducible representations (“irreps”) foretold by characters or traces

Subgroup splitting or correlation frequency formula:

f(α)(D(α)(G)↓H)

Atomic ℓ-level or 2ℓ+1-multiplet splitting

     D3 examples for ℓ=1-6

Group invariant numbers: Centrum, Rank, and Order


2nd-Stage spectral decompositions of global/local D3

Splitting class projectors using subgroup chains D3C2 and D3C3

Splitting classes


3rd-stage spectral resolution to irreducible representations (irreps) and Hamiltonian eigensolutions

Tunneling modes and spectra for D3C2 and D3C3 local subgroup chains

Lecture 16 Local-symmetry eigensolutions and vibrational modes (3.19.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774 , QTCA Unit 5 Ch. 15)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 4)



Review Stage 1: Group Center: Class-sums κg , characters χμ(g),

and All-Commuting Projectors Pμ

Review Stage 2: Group operators g and Mutually-Commuting projectors Pμkk

Review Stage 3: Weyl g-expansion in irreps Dμjk(g)

and Non-Commuting projectors Pμjk


Simple matrix algebra Pμab Pνcd = δμνδbcPμad

Pμjk transforms right-and-left

Pμjk -expansion in g-operators

Example of D3 transformation by matrix DEjk(r1)


Details of Mock-Mach relativity-duality for D3 groups and representations

Lab-fixed(Extrinsic-Global) vs. Body-fixed (Intrinsic-Local)

Hamiltonian and D3 group matrices in global and local P(μ)〉-basis


Hamiltonian and D3 group matrices in global and local P(μ)〉-basis

Global vs. Local block rearrangement

Hamiltonion eigen-matrix calculation

Hamiltonian local-symmetry eigensolution

Molecular vibrational mode eigensolution

Local symmetry limit 1

Global symmetry limit (free or “genuine” modes)


Lecture 17 Vibrational modes and symmetry reciprocity: Induced reps (3.20.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774; QTCA Unit 5 Ch. 15)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 4)



Review: Hamiltonian local-symmetry eigensolution in global and local ⏐P(μ)〉-basis


Molecular vibrational modes vs. Hamiltonian eigenmodes

Molecular K-matrix construction

D3 ⊃ C2(i3) local-symmetry K-matrix eigensolutions

D3-direct-connection K-matrix eigensolutions

D3C3(r±1) local symmetry K-matrix eigensolutions


Applied symmetry reduction and splitting

Subduced irep Dα(D3)↓C2 = d02d12⊕.. correlation

Subduced irep Dα(D3)↓C3 = d03d13⊕.. correlation


Spontaneous symmetry breaking and clustering: Frobenius Reciprocity , band structure

Induced rep da(C2)↑D3 = DαDβ⊕.. correlation

Induced rep da(C3)↑D3 = DαDβ⊕.. correlation


D6 symmetry and Hexagonal Bands

Cross product of the C2 and D3 characters gives all D6 = D3 ×C2 characters and ireps

Induced rep da(C2)↑D6 = DαDβ⊕.. correlation

Induced rep da(C6)↑D6 = DαDβ⊕.. correlation

Lecture 18 Hexagonal D6⊂D6h and octahedral-tetrahedral O~Td symmetry (3.31.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774 , QTCA Unit 5 Ch. 15)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 4)



Review: Symmetry reduction and splitting: Subduced irep Dα(D3)↓C2 = d02d12⊕.. correlation

     Symmetry induction and clustering: Induced rep hda(C2)↑D3 =DαDβ⊕.. correlation

Review: Review: Symmetry reduction and splitting: Subduced irep Dα(D3)↓C3 = d03d23⊕.. correlation

     Symmetry induction and clustering: Induced rep dc(C3)↑D3 =DαDβ⊕.. correlation


D3-C2 Coset structure of dm2(C2)↑D3 induced representation basis

D3-Projection of dm2(C2)↑D3 induced representation basis

Derivation of Frobenius reciprocity


D6D2 ⊃ C2 = D3 ×C2 symmetry and outer product geometry

Irreducible characters

Irreducible representations

Correlations with D6 characters:

...and C2(i3) characters......and C6(1, h1, h2,...) characters

D6 symmetry and induced representation band structure


Introduction to octahedral and tetrahedral symmetry: Oh ⊃ O ~ Td ⊃ T

Lecture 19 Octahedral-Tetrahedral O ~ Td symmetries (4.2.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774 , QTCA Unit 5 Ch. 15)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 4)



Introduction to octahedral/ tetrahedral symmetry Oh ⊃ O ~ Td ⊃ T

Octahedral-cubic O symmetry and group operations

Tetrahedral symmetry becomes Icosahedral

Octahedral groups Oh ⊃ O ~ Td ⊃ T

Octahedral O and spin-O ⊂ U(2)


Tetrahedral T class algebra

Tetrahedral T class minimal equations

Tetrahedral T class projectors and characters


Octahedral O class algebra

Octahedral O class minimal equations

Octahedral O class projectors and characters


Octahedral Oh ⊃ O: Inversion (g&u) parity

Octahedral Oh ⊃ O ⊃ CI subgroup correlations

Oh ⊃ O ⊃ D4 subgroup correlations

Oh ⊃ O ⊃ D4C4 subgroup correlations

Preview of applications to high resolution spectroscopy


Lecture 20 Octahedral-Tetrahedral O ~ Td Representations and Spectra (4.7.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774 , QTCA Unit 5 Ch. 15)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 4)



Review: Octahedral Oh ⊃ O group operator structure


Review: Octahedral Oh ⊃ O ⊃ D4C4 subgroup chain correlations



Comparison of O ⊃ D4C4 and O ⊃ D4D2 correlations and level/projector splitting

O ⊃ D4C4 subgroup chain splitting

O ⊃ D4D2 subgroup chain splitting (nOrmal D2 vs. unOrmal D2)

Oh ⊃ O ⊃ D4C4 and Oh ⊃ O ⊃ D4C4vC2v subgroup splitting


Splitting O class projectors Pμ into irreducible projectors Pμm4m4 for OC4

Development of irreducible projectors Pμm4m4 and representations Dμm4m4

Calculating PE0404 , PE2424, PT10404, PT11414, PT22424, PT21414


OC4 induced representation 04(C4)↑O ~ A1T1E and spectral analysis examples

Elementary induced representation 04(C4)↑O

Projection reduction of induced representation 04(C4)↑O

Introduction to ortho-complete eigenvalue-parameter relations

Examples in SF6 spectroscopy

Lecture 21 Octahedral Oh ⊃ subgroup tunneling parameter modeling (4.7.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774 , QTCA Unit 5 Ch. 15)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 4)



Review: Calculating idempotent projectors Pμm,m of OC4:

      PE0404 , PE2424, PT10404, PT11414, PT22424, PT21414

Review: Coset factored splitting of OD4C4 projectors

Review: Broken-class-ordered splitting of OD4C4 projectors and levels


Subgroup-defined tunneling parameter modeling

Comparing two diagonal OC4 parameter sets to SF6 spectra

Comparing two diagonal OC3 parameter sets to SF6 spectra

Why OC2 parameter sets require off-diagonal nilpotent Pμm,n (m≠n)

Irreducible nilpotent projectors Pμm,n (m≠n)

Using fundamental Pμm,n relations: ( from Lecture 16):

      (a) Pμm,mgPμn,n=Dμm,n(g)Pμm,n

      (b) gμΣm,nDμm,n(g)Pμm,n

      (c) Pμm,n=(ℓμ/°G)ΣgDμ*m,n(g)g

Review of D3C2 ~ C3v ⊃ Cv

Calculating and Factoring PT11404 and PT11434


Structure and applications of various subgroup chain irreducible representations

OhD4hC4v , OhD3hC3v , OhC2v

Comparing OhD4hD2h and OhD3dC2 representations (T1 vector-type)

Examples of off-diagonal tunneling coefficients DE0424

Comparing Local C4, C3, and C2 symmetric spectra

When Local C2 symmetry dominates

Comparing off-diagonal OC2 parameter sets to CH4 models with “cluster-crossings”


Lecture 22 Harmonic oscillator symmetry U(1) ⊂ U(2) ⊂ U(3) I. (4.14.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774 , QTCA Unit 7 Ch. 20-22)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 8)



1-D aa algebra of U(1) representations

Creation-Destruction aa algebra

Eigenstate creationism (and destruction)

Vacuum state

1st excited state

Normal ordering for matrix calculation

Commutator derivative identities

Binomial expansion identities

Matrix 〈ana†n〉 calculations

Number operator and Hamiltonian operator

Expectation values of position, momentum, and uncertainty for eigenstate ⏐n〉

Harmonic oscillator beat dynamics of mixed states

Oscillator coherent states (“Shoved” and “kicked” states)

Translation operators vs. boost operators

Applying boost-translation combinations

Time evolution of coherent state

Properties of coherent state and “squeezed” states


2-D aa algebra of U(2) representations and R(3) angular momentum operators

Lecture 23 Harmonic oscillator symmetry U(1) ⊂ U(2) ⊂ U(3) II. (4.17.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774 , QTCA Unit 7 Ch. 21-22)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 8)



Review: 1-D aa algebra of U(1) representations

Review: Translate T(a) and/or Boost B(b) to construct coherent state

Review: Time evolution of coherent state (and “squeezed” states)


2-D a†a algebra of U(2) representations and R(3) angular momentum operators

2D-Oscillator basic states and operations

Commutation relations

Bose-Einstein symmetry vs Pauli-Fermi-Dirac (anti)symmetry

      Anti-commutation relations

Two-dimensional (or 2-particle) base states: ket-kets and bra-bras

      Outer product arrays

      Entangled 2-particle states

Two-particle (or 2-dimensional) matrix operators

U(2) Hamiltonian and irreducible representations

2D-Oscillator states and related 3D angular momentum multiplets


R(3) Angular momentum generators by U(2) analysis

Angular momentum raise-n-lower operators s+ and s-

SU(2) ⊂ U(2) oscillators vs. R(3) ⊂ O(3) rotors

Lecture 24 Rotational symmetry U(2) ⊂ U(3) and O(3) (4.21.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774 , QTCA Unit 7 Ch. 21-22)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 5, 7)



Review: 2-D aa algebra of U(2) representations


Angular momentum generators by U(2) analysis

Angular momentum raise-n-lower operators s+ and s-

SU(2) ⊂ U(2) oscillators vs. R(3) ⊂ O(3) rotors


Angular momentum commutation relations

Key Lie theorems


Angular momentum magnitude and uncertainty

Angular momentum uncertainty angle


Generating R(3) rotation and U(2) representations

Applications of R(3) rotation and U(2) representations

Molecular and nuclear wavefunctions

Molecular and nuclear eigenlevels

Generalized Stern-Gerlach and transformation matrices

Angular momentum cones and high J properties

Lecture 25 Introduction to Rotational Eigenstates and Spectra I. (4.24.15)  View on YouTube

(Int.J.Mol.Sci, 14, 714(2013) p.755-774 , QTCA Unit 7 Ch. 21-25)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 5, 7)



Three (3) applications of R(3) rotation and U(2) unitary representations DJmn(α,β,γ)


1. Atomic and molecular DJ*mn(α,β,γ)-wavefunctions

“Mock-Mach” lab-vs-body-defined states |Jmn〉=PJmn|(0,0,0)〉= d(α,β,γ)DJ*mn(α,β,γ)R(α,β,γ)|(0,0,0)〉


2. R(3) rotation and U(2) unitary DJmn(α,β,γ)-transformation matrices

General Stern-Gerlach and polarization transformations R(α,β,γ)|Jmn〉=Σm′ DJm'n(α,β,γ)|Jm'n

Angular momentum cones and high J properties


3. Atomic and molecular multipole Hamiltonian tensor operators Tqk and eigenvalues

Multipole Tqk expansion of asymmetric-rotor Hamiltonians H = AJx2+BJy2+CJz2

Multipole Tqk expansion of symmetric-rotor Hamiltonians H = BJx2+BJy2+CJz2

Rotational Energy Surfaces (RE or RES) of symmetric rotor and eigensolutions

Rotational Energy Surfaces (RE or RES) of asymmetric rotor and energy levels


Sketch of modern molecular electronic, vibrational, and rotational spectroscopy

Example of CO2 rovibrational (υ=0) ⇔ (υ=1) bands


Introduction to RE symmetry and RES analysis of rovibrational Hamiltonians

Asymmetric Top eigensolutions for J = 1, 2

Lecture 26 Introduction to Rotational Eigenstates and Spectra II. (4.28.15)  View on YouTube

Based on AMOP Lectures 14-20

(Int.J.Mol.Sci, 14, 714(2013) p.755-774 , QTCA Unit 7 Ch. 21-25)

(Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 5, 7)



Review: Symmetric rigid quantum rotor analysis of R(2) Hamiltonian H = BJx2+BJy2+CJz2

Review: Rotational Energy Surfaces (RE or RES) and R(3) ~ U(2) representations


Asymmetric rigid quantum rotor analysis of D2 Hamiltonian H = AJx2+BJy2+CJz2

RES and Multipole Tqk tensor expansions

Atomic or molecular R(3) ℓ-level or 2ℓ+1-multiplet splitting

R(3) ⊃ D2 character analysis of ℓ-level or 2ℓ+1-multiplet splitting in D2

Detailed angular momentum operator analysis for J = 1-2 for D2 symmetry

      Asymmetric rotor levels and RES plots for high-J


Octahedral semi-rigid quantum rotor analysis of Oh Hamiltonian H = BJ•J + t044T[4]

Spherical rotor levels and RES plots of Oh tensor eigenvalues

R(3) ⊂ O(3) ⊃ Oh ⊃ O character analysis of ℓ-level or 2ℓ+1-multiplet splitting in O

SF6 spectral fine structure P(88)

CF4 spectral fine structure P(54)

Lecture 27 Introduction to Rotational Eigenstates and Spectra III. (4.28.15)  View on YouTube

Based on: QTCA Lectures 24-25 (2013); AMOP Lectures 17-18 (2014)

Int.J.Mol.Sci, 14, 714(2013) p.755-774; Computer Phys. Reports 8,319-394 (1988)

(QTCA Unit 7 Ch. 21-25; Principles of Symmetry, Dynamics, and Spectroscopy - Ch. 5, 7)


Review: Asymmetric rotor levels of H = AJx2+BJy2+CJz2 and RES plots

D2 ⊃ C2 symmetry correlation


Review: Spherical rotor levels and RES plots

Spectral fine structure of SF6, SiF4, C8H8, ...

O ⊃ C4 and O ⊃ C3 symmetry correlation

Some more examples of J=30 levels (including T[6] vs T[4] effects)



Details of P(88) v4 SF6 and P(54) v4 CF4 spectral structure and implications

Beginning theory

Rovibronic nomograms and PQR structure

Rovibronic energy surfaces (RES) and cone geometry

Spin symmetry correlation, tunneling, and entanglement

Hyperfine vs. superfine structure (Case 1. vs Case 2.)

Spin-0 nuclei give Bose Exclusion

      The spin-symmetry species mixing problem

Analogy between PE surface dynamics and RES

Rotational Energy Eigenvalue Surfaces (REES)

Lecture 28 Rotational energy and eigenstate surfaces for Coriolis dynamics (4.30.15)

Lecture 29 Rotational eigenstates and spin-permutation symmetry (4.30.15)

Lecture 30 Symmetry product analysis U(m)*Sn tensors (4.30.15)