TFY4210 Kvanteteori for mangepartikkelsystem

Spring 2013


Lecturer:
Associate professor John Ove Fjærestad (office: E5-126, email: john.fjaerestad@ntnu.no, phone: 93448)

Contents:
Klein-Gordon and Dirac equation. Field quantization. Occupation number representation for nonrelativistic fermionic and bosonic many-particle systems. Interacting electron gas. Lattice models for fermions and spins. Spin-wave theory of ferro- and antiferromagnets. Symmetries and conserved quantities. Broken symmetries, Goldstone modes. Green functions. Matsubara formalism. Many-particle perturbation theory and Feynman diagrams. Various applications.

Lectures:
Tuesdays 10:15-12:00 and Thursdays 9:15-10:00 in E5-103.

Tutorials:
Thursdays 8:15-9:00 in E5-103 (starting in week 4).
As a pre-exam requirement, each student will present solutions to one or more tutorial problems at at least one tutorial (more details will be provided later).

Reference group:
Espen Auseth Nielsen (espenani@stud.ntnu.no)
NN (one more student needed)

Exam:
Friday 7 June, 09.00-13.00.
You may bring:
- an approved calculator
- Rottmann: Matematisk formelsamling/Mathematische Formelsammlung
- Barnett and Cronin: Mathematical Formulae for Engineering and Science Students

Exam (Norwegian, English)
Solution (English only)
Grades

Pre-exam Q&A session:
Tuesday 4 June at 11:15 in E5-103.

Curriculum:

The curriculum ("pensum") for the exam is based on the material that has been covered in lectures, plus the written solutions to the tutorial problems. For the lecture material one may alternatively use the following notes/sources:

- Second quantization
- Second quantization representation for the Hamiltonian of an interacting electron gas
- Noninteracting electrons. The free electron gas
- Tight-binding model for electrons in a crystal (sec. 2 + appendix; note that sec. 1 is just a slightly more primitive version of the notes linked to on the previous line)
- The Hubbard and Heisenberg models, spin-wave theory of ferro- and antiferromagnets, broken symmetry and Goldstone modes
- Transformations and symmetries in quantum mechanics
- Introduction to Green functions and many-body perturbation theory (except Secs. 4.9 and 4.10)
- The Klein-Gordon equation: Sec. 17.1 in Hemmer's "Kvantemekanikk", except the derivation of Eq. (17.18) (which starts in Eq. (17.7)) and Sec. 17.1.3.
- The Dirac equation: Sec. 17.2 in Hemmer, except Sec. 17.2.4.c about helicity.

Note that the following topics which were discussed in lectures (some of them only briefly) are not examinable:

- the material on Bloch and Wannier states discussed before the tight-binding model (but note that the material on the tight-binding model is examinable, cf. notes above)
- the detailed derivation (using projection operators) of the S=1/2 Heisenberg antiferromagnetic model from the half-filled Hubbard model in the strong-interaction limit
- the Mermin-Wagner theorem
- aspects of broken symmetry that are not covered in Sec. 6 of the magnetism notes (but, to be clear, the material in that section is examinable)
- the hand-out from Bruus and Flensberg about impurity self-averaging
- the Kubo formula for the conductivity (Secs. 4.9 and 4.10 in the Green function notes)


Resources:

Main resources:
Notes by the lecturer (will be made available on the website as the course progresses).

Supporting resources:
There is no single textbook that covers all the material that will be discussed in the course. Much of the material on non-relativistic quantum many-particle systems is covered in "Many-body quantum theory in condensed matter physics" by Bruus and Flensberg (Oxford, 2004), which is the main recommended textbook for this part of the course. Other recent textbooks in the same area that may be useful are "Condensed matter field theory" by Altland and Simons (2nd ed., Cambridge, 2010) and "Introduction to many body physics" by Piers Coleman (Cambridge, 2012; a pre-publication copy is available here). An old classic is "Quantum theory of many-particle systems" by Fetter and Walecka from 1971 which is available in a non-expensive paperback version (Dover, 2003). The main reference on the quantum magnetism material is "Interacting electrons and quantum magnetism" by Auerbach (Springer, 1994). In the last part of the course we plan to discuss some relativistic systems. The main reference for that part will be "Quantum theory of many-particle systems", lecture notes for TFY4210, 2nd ed., 2011, by J. O. Andersen. Other references will be provided later.


Lecture notes etc.:

(please let me know if you find errors, typos, or unclear statements in the notes)

Second quantization
Second quantization representation for the Hamiltonian of an interacting electron gas
Noninteracting electrons. The free electron gas
Electrons in a crystal: Bloch and Wannier states (in preparation), tight-binding model (in preparation; 2012 version)
The Hubbard and Heisenberg models (in preparation; 2012 version)
Spin-wave theory of ferro- and antiferromagnets (in preparation; 2012 version)
Transformations and symmetries in quantum mechanics
Symmetry breaking (in preparation; 2012 version)
Introduction to Green functions and many-body perturbation theory (may be updated later)
About impurity (self-)averaging (from Bruus and Flensberg)


Tutorial sets:

Tutorial Date Presenter Problems Solution
1 24 Jan Tobias Grøsfjeld
tfy4210-tut-01-2013.pdf
tfy4210-tut-01-2013-sol.pdf
2 31 Jan Oladunjoye Awoga
tfy4210-tut-02-2013.pdf
tfy4210-tut-02-2013-sol.pdf
3 07 Feb ---
tfy4210-tut-03-2013.pdf
tfy4210-tut-03-2013-sol.pdf
4 14 Feb Espen Auseth Nielsen
tfy4210-tut-04-2013.pdf
tfy4210-tut-04-2013-sol.pdf
5 21 Feb ---
tfy4210-tut-05-2013.pdf
tfy4210-tut-05-2013-sol.pdf
6 28 Feb Espen Undheim
tfy4210-tut-06-2013.pdf
tfy4210-tut-06-2013-sol.pdf
7 07 Mar Runar Skålbones
tfy4210-tut-07-2013.pdf
tfy4210-tut-07-2013-sol.pdf
8 14 Mar ---
tfy4210-tut-08-2013.pdf
tfy4210-tut-08-2013-sol.pdf
9 21 Mar Ravinder Gill
tfy4210-tut-09-2013.pdf
tfy4210-tut-09-2013-sol.pdf
10 11 Apr ---
tfy4210-tut-10-2013.pdf
tfy4210-tut-10-2013-sol.pdf
11 18 Apr Magnus Eik
tfy4210-tut-11-2013.pdf
tfy4210-tut-11-2013-sol.pdf
12 30 Apr Felix Prinz
tfy4210-tut-12-2013.pdf
tfy4210-tut-12-2013-sol.pdf


Other:

Past exams
2012 course website


Last update: 4 Jul 2013 at 13:35