In this part: 1. Algebraic method for harmonic oscillator - creation and annihilation operators a+ and a this is needed to treat each of the eigenmodes ( each one is an independent oscillator ) 2. Quantum theory of the electromagnetic field - two expressions for energy of the field in eigenmodes, using a+ and a and using the derived operators for electric and magnetic field strengths 3. From Lorentz Force to hamiltonian of charged particle in electric - and magnetc - field ATOM-FIELD INTERACTION 4. Applying the golden rule - what will be the matrix elements |
Algebraic method for the Harmonic oscillator - Creation and annihilation of "energy quanta" The next three (smaller size slides) were shown at the end of LAST TIME the hamiltonian is transformed to simple and symmetric, dimensionless-operator based form Linear combination of this dimensionless coordinate Q and momentum P - leads to annihilation / creation operators |
1220_Harmonic_Oscillator_Creation_Annihilation.png
1220_Harmonic_Oscillator_Creation_Annihilation.png |
Algebraic method for the Harmonic oscillator - Creation and annihilation of "energy quanta" Linear combination of this dimensionless coordinate Q and momentum P - leads to annihilation / creation operators ONLY USING commutation relations |
1230_Harmonic_Oscillator_Creation_Annihilation.png
1230_Harmonic_Oscillator_Creation_Annihilation.png |
Linear combination of this dimensionless coordinate Q and momentum P - leads to annihilation / creation operators ONLY USING commutation relations Hamiltonian Number operator eigenstates characterized by "number of quanta" |
1250_Harmonic_Oscillator_Creation_Annihilation.png
1250_Harmonic_Oscillator_Creation_Annihilation.png |
Linear combination of this dimensionless coordinate Q and momentum P - leads to annihilation / creation operators ONLY USING commutation relations creation and annihilation operators a+ and a Hamiltonian Number operator eigenstates characterized by "number of quanta" |
005_creations_commutations.png
005_creations_commutations.png |
Ladder operators creation and annihilation operators a+ and a |
006_Quanta_Number__LADDER_operator.png
006_Quanta_Number__LADDER_operator.png |
Looking back at the wavefunction formulation operators a+ and a are in fact partly differentiation ...... Schrödinger equation - replaced by effective first order differential equation |
007_differential_eq-via_Ladder_operator.png
007_differential_eq-via_Ladder_operator.png |
Quantum theory of the electromagnetic field - two expressions for energy of the field in eigenmodes, using a+ and a and using the derived operators for electric and magnetic field strengths Establishing the dimensional constant ( from the equality of the two energies ) |
008_Quantum_Description_of
Field_vector_pot_A.png
008_Quantum_Description_of Field_vector_pot_A.png |
Establishing the dimensional constant ( from the equality of the two energies ) |
010_Classical_Quantum_total_energy_same_M.E.png
010_Classical_Quantum_total_energy_same_M.E.png |
ATOM-FIELD INTERACTION From Lorentz Force to hamiltonian of charged particle in electric - and magnetc - field |
018Charged_Particle_Lorentz_Force.png
018Charged_Particle_Lorentz_Force.png |
ATOM-FIELD INTERACTION hamiltonian of charged particle in electric - and magnetc - field |
019_Field_Atom_Interaction.png
019_Field_Atom_Interaction.png |
ATOM-FIELD INTERACTION hamiltonian of charged particle in electric - and magnetc - field a map of the steps in applying Golden Rule identifying the H0 and H1 |
020_Hamilton_Field_Atom_Interaction.png
020_Hamilton_Field_Atom_Interaction.png |
ATOM-FIELD INTERACTION applying Golden Rule identifying the H0 and H1 initial and final (continuum) states |
030_Apply_Golden_Rule_to_Atom_Field.png
030_Apply_Golden_Rule_to_Atom_Field.png |
Discussing details of the resulting matrix element what are electronic (red) and what are field (blue) components the field is quantized, its description is in terms of creation / annihilation expressions but the "eigenmodes" are in the normal 3-dim space - so they will be the same as the electron coordinates ( the exp(- i k r ) - r is the same coordinate as the electron ) |
060_Matrix_Element.png
060_Matrix_Element.png |
Note above the sign in the exponentials - ( discussed also in the next lecture ) now changed in agreement with literature - but is seemingly opposite to our usual conventions for plane waves In the NEXT LECTURE we carry through the details of the light emission rates and discuss the stimulated emission in this framework |