Regular Courses
at IFT (Portuguese and English)
Quantum Field Theory II - 1st Semester, 2024
- Credits: 12 (in "hours per week")
Prerequisites: Quantum Field Theory I (specifically the subjects covered here)
Meetings: twice a week (according to this schedule)
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Overview:
We will go through the syllabus below keeping a notation and conventions closer to ref [2] (which is also used by many other QFT books). It is assumed that students have already studied Quantum Field Theory, understand the quantization of field theories both in the canonical and path integral approaches and are capable of calculating tree level processes. This course is (finally) a natural continuation of the QFT I course I offered in the last three years, therefore details on the subjects already covered can be found here.
Grades will be based on exercises, active participation in the meetings and a seminar (to be given by each student at the course's end).
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Video lectures:
We will not have in-class lectures per se. There will be videos (one or two videos per lecture) on YouTube, and the students are expected to watch them and work through the exercises. This can be very profitable for students as long as an active stance is taken (and it will be total crap for passive students, beware). Take full advantage of watching the lecture in video format: stop, rewind, skip, check notes and references as needed, speed up the video when I'm going too slow (as is often the case).
You can use the Visual Subject Guide to quickly navigate through the videos (clicking on the PDF will take you to the corresponding video).
Twice a week there will be a meeting/lecture in which the students are expected to discuss the subjects in the videos and present the exercises. The discussion will be only profitable to those that did prepare properly.
Below are the links to the videos needed for each lecture and the corresponding pages in my lecture notes.
- Lecture 1 (Lagrangians and Observables, Källén–Lehmann Representation): video 1 and video 2 - Lecture Notes pgs 1-9 (Mar 8)
- Lecture 2 (Polology): video 3 - Lecture Notes pgs 10-14 (Mar 15)
- Lecture 3 (LSZ Reduction Formula): video 4 - Lecture Notes pgs 14-19 (Mar 19)
- Lecture 4 (Field and Mass Renormalization): video 5 - Lecture Notes pgs 19-24 (Mar 22)
- Review 1 (1PI Diagrams and the Effective Action): QFT I - video 25 and QFT I - video 26 - QFT I Lecture Notes pgs 172-183 (Apr 2)
- Lecture 5 (Vertex Functions and Coupling Renormalization): video 6 - Lecture Notes pgs 24-29 (Apr 5)
- Lecture 6 (One-loop λΦ4, Pauli-Villars Regularization): video 7 - Lecture Notes pgs 29-36 (Apr 9)
- Lecture 7 (Feynman Parametrization and Wick Rotation): video 8 - Lecture Notes pgs 37-46 (Apr 12)
- Lecture 8 (Dimensional Regularization in λΦ4): video 9 - Lecture Notes pgs 46-53 (Apr 16)
- Lecture 9 (Power Counting and Renormalizability in λΦn): video 10 - Lecture Notes pgs 54-61 (Apr 19)
- Lecture 10 (Power Counting and Renormalizability at higher loop order and more general theories): video 11 and video 12 - Lecture Notes pgs 61-66 (Apr 23)
- Lecture 11 (Non-renormalizable theories. Ward-Takahashi Identities): video 13 and video 14 - Lecture Notes pgs 66-75 (Apr 26)
- Lecture 12 (Renormalization of QED I, Power Counting and Counterterms): video 15 - Lecture Notes pgs 75-83 (Apr 30)
- Lecture 13 (Renormalization of QED II, Formal Structure of the QED Vertex): video 16 - Lecture Notes pgs 83-90 (May 3)
- Lecture 14 (Renormalization of QED III, Photon Self Energy): video 17 - Lecture Notes pgs 90-96 (May 7)
- Lecture 15 (Renormalization of QED IV, Physics of Π(q2), Running Charge): video 18 - Lecture Notes pgs 96-101 (May 10)
- Lecture 16 (Renormalization of QED V, Electron Self Energy and the MS Scheme): video 19 - Lecture Notes pgs 102-109 (May 14)
- Lecture 17 (Renormalization of QED VI, Vertex Corrections and g-2): video 20 - Lecture Notes pgs 109-114 (May 17)
- Lecture 18 (Renormalization of QED VII, Infrared Divergences): video 21 - Lecture Notes pgs 114-122 (May 21)
- Lecture 19 (The Optical Theorem and Unstable Particles): video 22 - Lecture Notes pgs 122-128 (May 24)
- Lecture 20 (Wilsonian Renormalization I, Coarse Grainining and Momentum Shell Integration): video 23 - Lecture Notes pgs 128-134 (May 28)
- Lecture 21 (Wilsonian Renormalization II, Renormalization Group Transformations): video 24 - Lecture Notes pgs 134-142 (June 4)
- Lecture 22 (Renormalization Group Equations and the Callan-Symanzik Equation): video 25 - Lecture Notes pgs 143-149 (June 7)
- Lecture 23 (Beta (β) and Gamma (γ) Functions): video 26 - Lecture Notes pgs 149-156 (June 11)
- Lecture 24 (Solving the Callan-Symanzik Equation): video 27 - Lecture Notes pgs 157-163 (June 14)
- Lecture 25 (RGE applications: running of electric charge, fixed points, anomalous dimensions and running mass): video 28, video 29 and video 30 - Lecture Notes pgs 163-171 (June 18)
- Lecture 26 (Evolution of Mass Parameters and Critical Exponents): video 31 and video 32 - Lecture Notes pgs 171-181 (June 21)
- Lecture 27 (Non-abelian QFTs: Lie Algebras and Yang-Mills Theory, Quantization of non-Abelian Gauge Theories, Faddeev-Popov Method): video 33, video 34 and video 35 - Lecture Notes pgs 182-197 (June 25)
- Lecture 28 (Faddeev-Popov Ghosts and Unitarity, Asymptotic Freedom): video 36 and video 37 - Lecture Notes pgs 197-213 (June 28)
Attention: the lecture notes are in Portuguese (and will probably never get translated - there is already plenty of good material in English) and are intended more as an organizational tool for myself, and sometimes are used to make reference to equations in the exercises (it is easier than giving a time-stamp on a video). There are certainly many mistakes in these notes and they are badly organized. Use them only as a map to see what we are discussing, go to the bibliography for the real thing.
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Exercises:
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Syllabus:
(I) Radiative Corrections
Källén-Lehmann Spectral Representation
LSZ Reduction Formula
The relation between observable quantities and Lagrangian parameters
(II) Renormalization
Counting Ultraviolet Divergences
Perturbative Renormalization
(III) Renormalization Group Equations
Callan-Symanzik equation
Running of coupling constants and mass renormalization
(IV) Quantization of non-Abelian Gauge Theories
Faddeev-Popov method
Faddeev-Popov ghosts and unitarity;
Quantum Chromodynamics (QCD) and renormalization; asymptotic freedom
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Student Seminars:
Students are supposed to prepare a 40 minute seminar by the end of the course. The subject should be something beyond what has been discussed in the course, but which is a smooth extension of it.
Dates and subjects are listed below:
Friday, 21st of June, 2024:
- 16:00 - Quebra Expontânea de Simetria - Abdias Aires de Queiroz Neto
Monday, 1st of July, 2024:
- 14:00 - Renormalization Group Evolution of Flavour Invariants - Eduardo Lourenço Fabio de Lima
- 15:00 - Quebra de Simetrias Locais / Mecanismo de Higgs - Gustavo Santos
- 16:00 - Classical Observables from Scattering Amplitudes - Gabriel Macedo Dantas
- 17:00 - Teorias Efetivas e o Modelo de Nambu-Jona-Lasinio - Gustavo Barbosa Bopsin
- 18:00 - Entropia de emaranhamento do estado de vácuo de um campo escalar - Willy Antony Izquierdo Inga
Tuesday, 2nd of July, 2024:
- 14:00 - Charged Scalar Field and Bose-Einstein Condensation - Randall Hell Vargas Pradinett
- 15:00 - Curci-Ferrari model in Minkowski space - Maycol Clister Fernández Chillcce
- 16:00 - Conformal Field Theories in d>2 - Juliana Zanatta Finotti
- 17:00 - Introduction to supersymmetry breaking - Juan Dennis Tejeira Huacani
- Bibliography:
[1] H. Nastase, "Introduction to Quantum Field Theory"
[2] M.E. Peskin and D.V. Schroeder, "An introduction to Quantum Field Theory"
[3] L.H. Ryder, "Quantum Field Theory"
[4] G. Sterman, "An introduction to Quantum Field Theory"
[5] P. Ramond, "Field theory: A modern primer"
[6] S. Weinberg, "The Quantum Theory of Fields"
[7] M. D. Schwartz, "Quantum Field Theory and the Standard Model"
[8] T.-P. Cheng and L.-F. Li, "Gauge theory of elementary particle physics"
[9] A. Zee, "Quantum Field Theory in a Nutshell"
- Additional material:
[a] V. Kaplunovsky, Dirac Matrices and Lorentz Spinors (available here).
[b] Jaffe's piece on Natural Units
[c] Interesting discussions about the foundations and validity of Quantum Field Theories: focusing on Haag's Theorem and Perturbative Series & Renormalization.
[d] Marco Serone, Spectral representation for fermions: Notes on Quantum Field Theory, sec. 2.1.3.