The main purpose of this course is to learn the basic concepts and techniques behind the theory of quantum fields, with applications to elementary particle physics, in particular Quantum Electrodynamics.
- Apply the main principles to specific areas such as particle physics, astrophysics of stars, planets and galaxies, cosmology and physics beyond the Standard Model.
- Formulate and tackle problems, both open and more defined, identifying the most relevant principles and using approaches where necessary to reach a solution, which should be presented with an explanation of the suppositions and approaches.
- Use acquired knowledge as a basis for originality in the application of ideas, often in a research context. Use critical reasoning, analytical capacity and the correct technical language and formulate logical arguments.
- Use mathematics to describe the physical world, select the appropriate equations, construct adequate models, interpret mathematical results and make critical comparisons with experimentation and observation.
- Analyze the concept of renormalization and apply it in to electromagnetic processes.
- Apply the language of Feynman diagrams in quantum field theory .
- Apply quantum field theory electromagnetic processes.
- Calculate cross sections of electromagnetic processes .
- Understand the basics of quantum field theory.
1.2 Elements of classical field theory
1.2.1 Functional calculus
1.2.2 Lagrangian and Hamiltonian. Euler-Lagrange equations
1.3 Natural units
- Quantization of free fields
2.1 Non-relativistic fields. Bosons and Fermions. Number operator and statistics
2.2 Field of Klein-Gordon real. Propagators and causality
2.3 Continuous symmetries. Noether theorem: currents and energy-momentum tensor
2.4. Discrete symmetries: C,P,T
2.5 Field of Klein-Gordon complex. Charge symmetry
2.6 Dirac field. Propagators, symmetries, spin: helicity and quirality
2.7 Electromagnetic field
3.1 Cross section and S matrix
3.2 Interaction picture and S matrix
3.3 Wick theorem
3.4 First computation at tree level: $\lambda \phi^4$
3.5 Feynman diagrams
4.1 Quantization of QED
4.2 S-matrix to O(e^2)
4.3 Compton scattering at tree level. Feynman diagrams and computational techniques: traces, spin, …
4.4 About gauge invariance. Example of Ward identity
4.5 Generalized Feynman rules and for QED
4.6 Other elementary QED processes at tree level: e^+e^- -> \mu^+\mu^-, …
4.7 Radiative transitions of Hydrogen
- Beyond tree level. Introduction
5.1 Infinities and dimensional regularization
5.2 Vacuum polarization
5.3 Renormalization of the electric charge
5.4 Optical theorem
- Beyond perturbation theory
6.1 LSZ formalism and crossing symmetry (examples)
It is recommended to have followed the course Introduction to the Physics of the Cosmos.