Discussion of the homework exercises

20 Março 2020, 08:30 • Nuno Barros

Discussion of the solutions of the exercises of the previous weeks.

Dirac equation (continuation). Introduction to QED

18 Março 2020, 08:30 • Nuno Barros

• Dirac equation
  
• Revision of spin
• Introduction of helicity. Helicity eigenstates.
• Charge conjugation. Intrinsic parity of Dirac particles.
• Introduction to QED
• Interaction by particle exchange
• Time-ordering diagrams.
• Feynman diagrams. Virtual particles
• Feynman rules for QED

Interaction cross section. Introduction to Dirac equation.

13 Março 2020, 08:30 • Nuno Barros

• Derivation of Interaction cross section. Lorentz-invariant formulation
• Transformation to laboratory frame.
• Introduction to Dirac Equation
• Klein-Gordon equation
• Probability density and current
• Dirac equation
• Covariant formulation of the Dirac equation
• Solutions of the Dirac equation
• Free particle at rest
• Plane-wave solutions
• Interpretation of negative energy solutions
• Feynman-Stückelberg interpretation

Not Taught.

11 Março 2020, 08:30 • Nuno Barros

In-person classes suspended the day before. Not enough time to make arrangements for remote teaching. Subject covered in next TP class.

Decay rates and cross sections

6 Março 2020, 08:30 • Nuno Barros

• Review of previous lectures
• Demonstration of properties of the Dirac delta function
• Fermi's Golden Rule
• Non-relativistic formulation
• Phase space and wave function normalisation
• Lorentz-invariant formulation
• Particle decays