Semesterside for FYS4480 - H?st 2025

Dear all, this is our last week of lectures and the plan is to

Thursday:

Repetition from last week and wrapping up discussion of the CCD approach

Introducing a diagrammatic approach

How to write your own coupled-cluster theory code, pairing model example (follow-up from second midterm)

Coupled cluster theory, singles and doubles excitations, diagrammatic expansion

Friday:

Coupled cluster theory for singles and doubles excitations using a diagrammatic derivation

Summary of course and discussion of final oral exam

Lecture material: Lecture notes and Shavitt and Bartlett chapters 9 and 10. See also slides at?https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/pub/week48/pdf/cc.pdf and this week's slides at https://github.com/ManyBodyPhysics/FYS4480/blob/master/doc/pub/week48/ipynb/week48.ipynb

Best wishes to you all,

Morten

Dear all, here are our plans for week 47, November 17-21

Thursday:

a. Derivation of coupled cluster equations for doubles only

Friday:

a. Derivation of doubles excitation equation with diagrammatic expansion

b. Applications to the pairing model from the second midterm

c. Discussion and work on the second midterm

Lecture material: Lecture notes (these notes at https://github.com/ManyBodyPhysics/FYS4480/tree/master/doc/pub/week47) and chapter 9 of Shavitt and Bartlett, in particular sections 9-1-9.3

Best wishes to you all and good luck with the second midterm

Morten

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, 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...

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, 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. 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 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.

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, 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...