Semester page for FYS4480 - Autumn 2025

Dear all, first, a great thank you to everybody for heroic efforts with the first midterm.  It has been a pleasure to read through them. Feedback is planned for the end of next week. Let me also now if it is ok if we schedule the second midterm for the first half of november, that is sometime during the week which starts with November 10, with a tentative deadline around November 17 (Monday) or 18 (or later that week). That way we avoid overlapping with the second project in FYS-STK and potential exams in other courses (some start around November 25).  Each midterm counts 30% of the final grade.

Our last lecture with summary etc is planned to be November 28. We should also start planning the final oral exam (which counts 40% of the final grade). Since we are quite many, we will need two full days (45 mins per candidate).  I know that FYS4170 has a scheduled exam on Dec 19. We could then opt for December 15 and 16,  with the 15th reserved for th...

Dear all, welcome back to FYS4480/9480.

The plans this week are to first finalize our discussions of the homogeneous electron gas in three dimensions by calculating the Hartree-Fock ground state energy. After this long detour we will get an expression for the energy which is a function of the density of the system. This serves as one of the starting points for density functional theory (which we discuss later today and partly tomorrow) and is known as the local density approximation.

Some of the derivation are not included in the slides for this week and will be presented during the lectures. 

Else, we will use parts of Friday's lecture to discuss and work on the first midterm.

The plans are with, with link to the lecture notes https://github.com/ManyBodyPhysics/FYS4480/tree/master/doc/...

First midterm, with deadline October 20

Here's the first midterm, we will discuss it during the exercise sessions and partly during the lectures on Friday October 10.

The link is at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/Exercises/2025/FirstMidterm2025.pdf

Best wishes.

Dear all, welcome back to FYS4480/9480.  This week we plan to

Thursday:

1. Stability of Hartree-Fock theory, wrapping up discussions from lecture October 3, see slides from last week

2. The homogeneous electron gas in three dimensions

       -Hartree-Fock solution and ground state energy

Friday:

1. Calculating the ground state energy of the electron gas

2. Discussion of first midterm

3. Lecture Material: These slides (see the attached pdf-file) and handwritten notes

4. First midterm set at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/Exercises/2025/FirstMidterm2...

Dear all, welcome back to FYS4480/9480.

This week, and the two coming ones, we will spend time on mean-field theories, starting with Hartree-Fock theory and then moving to density functional theory. The plan this week is to

Topics to be covered

Thursday:

a. Deriving the Hartree-Fock equations

b. Efficient ways of implementing the Hartree-Fock algorithm

Friday:

a. Stability of Hartree-Fock equations and Thouless' theorem

Lecture Material: These slides attached here and Szabo and Ostlund, sections 3.1-3.4

Seventh exercise set at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/Exercises/2025/ExercisesWeek40.pdf

Best wishes to you all,

Morten

Dear all and welcome back to a new week with FYS4480/9480. The plans this week are 

Thursday:

• Discussion of Full configuration interaction (FCI) theory
• Diagrammatic representation of FCI
• Lipkin model as an example of applications of FCI theory                                                                                                                                                                          &nbs...

Dear all, welcome back to FYS4480/9480. First, please excuse me for sending this mail late, I simply forgot to send yesterday. 

I have also made some changes to the schedule from last week. I decided that instead of making a video of the particle-hole formalism, I opted for a regular lecture today instead.  Also, I have posted (see link below)  solution to the exercises from last week. They contain also a discussion of the parts of the exercises this week (exercise 1). Exercise 2 will be discussed during the lectures today and tomorrow.  
The plan this week is thus to

Thursday: Discussion of particle-hole formalism with examples and diagrammatic representation.
Friday: Full configuration interaction theory

Lecture Material: These slides and chapters 3 and 4 of Shavitt and Bartlett covers most of the material discussed this week.

Fifth exercise set at https://github.com/ManyBodyPhysics/FYS...

Dear all, welcome back to FYS4480/9480.

This week we will use the lecture on Thursday to summarize our discussions on Wick's theorem, with examples and discussions of the exercise set this week. We will also introduce a new reference vacuum state and the so-called particle-hole formalism, widely used in condensed matter physics, materials science, quantum chemistry and nuclear physics. This topic continues on Friday. 

For Wick's theorem, chapters 3 and 4 of Shavitt and Bartlett is an ok read. idem for the particle-hole formalism.

Lecture Material: slides from https://manybodyphysics.github.io/FYS4480/doc/pub/week37/pdf/week37.pdf.

Fourth exercise set at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/Exercises/2025/ExercisesWeek37.pdf

The solution to the exercises from week 36 are at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/Exercises/2025/AnswersWeek36.pdf

Best wishes to you all,

Morten

Dear all, welcome back to FYS4480/9480.

This week we aim at discussing the following topics:

-Thursday: Second quantization, operators in second quantization and diagrammatic representation. Discussion of Wick's theorem

-Friday: Second quantization and Wick's theorem

Lecture Material and reading suggestions: slides from https://manybodyphysics.github.io/FYS4480/doc/pub/week36/pdf/week36.pdf, handwritten notes and Szabo and Ostlund sections 2.3 and 2.4. The material on Wick's theorem is covered by the whiteboard notes to be discussed on Thursday and Friday.

The third exercise set is at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/Exercises/2025/ExercisesWeek36.pdf

The solution to the exercises from week 35 are at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/Exe...

Dear all, we hope this week started the best possible for all of you.

Here are some updates for this week (week 35).  On Thursday we plan to finalize the calculations of expectation values for fermionic systems. Parts of this material is covered by the lectures from last week, see for example the slides from last week at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/pub/week34/pdf/week34.pdf (from with Ground state energy as header).

Thereafter (Friday most likely), we move into our first encounter of second quantization. The material is covered by this week's slides at for example https://manybodyphysics.github.io/FYS4480/doc/pub/week35/html/week35-bs.html or as a pdf file at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/pub/week35/pdf/week35.pdf

Our second exercise set, to be discussed on Friday is available at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/Exercises/2025/ExercisesWeek35.pdf...