Teaching

It is to share the structure and the beauty of this academic discipline, physics. One can see the connection and the development of topics from basic to advanced courses in the curriculum. Newtonian mechanics (point particles and rigid bodies),  electromagnetic theory (classical fields), quantum mechanics (quantum particle & field), thermodynamics and statistical mechanics (classical/quantum many body particle & field), and advanced courses such as quantum computation, solid state physics, particle physics, relativity, plasma physics etc. They together constitute the minimum knowledge placing you upfront to the latest academic research.

2025 Spring: Quantum computer and technology (undergraduate course)

• The course covered the Lecture notes by Prof. J. Preskill. Physics 219 Course Information (caltech.edu) 

• We were able to cover more quantum algorithms this year. After covering quantum Fourier transformation, phase estimation, the periodicity finding, Grover search algorithms (they were taught last year as well), the Harrow–Hassidim–Lloyd (HHL) algorithm (to solve a number of coupled linear equation (Ref), variational quantum eigensolver (Hybrid classical-quantum computation), Kitaev toric code (Ref) were discussed in details. 

2024 Spring: Topological quantum matter (graduate course)

• The course will cover the book by D. Vanderbilt "Berry phases in electronic structure theory". Section 2.1.3 is our starting point.

• Later parts of the textbook, there are the introduction of Weyl semimetal and associated physics such as chiral anomaly and chiral magnetic effect. The phenomena are discussed based on the semiclassical equation of motion. It provides an intuitive physical picture, but in terms of formulation it leaves some unfilled rooms in mathematical derivations, since it is semiclassical. This year I adopted a review paper by Dr. Sekine and Dr. Nomura (Ref.) for our lecture on Weyl semimetal and the microscopic derivation of the topological term yielding the magneto-electric effect on the surface of 3D topological insulator. 

2024 Autumn: Statistical Physics (graduate course)

• It was my third time teaching the course at CAU. We used the textbook by Kardar, the field one, and covered up to Ch6, the real space RG. The conceptual transition from many body particle to iteracting fields is learned. Using the classical field theory, the perturbative RG is practiced, from which critical exponents are computed. Various critical exponents are bound to be related from the homogeneity assumption of free energy. 

• It will good to expand the concents of this course to out-of-equilibrium systems such as the KPZ and non-Hermitian systems. 

2024 Autumn: Statistical Physics (undergraduate course)

• It was my second time teaching the course, which covers the second half of the textbook by Schroeder from the liquid-gas phase transition (chapter 5) to the para- to ferro-magnetic phase transition (chapter 8). In between, examples of quantum particles are discussed: Fermi gas, blackbody radiation, the spontaneous emission, Bose-Einstein condensation, Deby theory of solids, Magnon and Mermin-Wagner theorem, van der Waals equation of state. 

2024 Autumn: General Physics II (undergraduate course)

• I taught the course for students from chemical engineering department. 

• Faraday and Maxwell showed the induction of magnetic field from electric field, and the vice versa. 

• Einstein showed that magnetic field in one inertia frame is electric field in another inertia frame. 

2024 Spring: Quantum computer and technology (undergraduate course)

• The course will cover the Lecture notes by Prof. J. Preskill. Physics 219 Course Information (caltech.edu) 

• Some students in the class teamed up and participated the national quantum information competition. They won the second place among undergraduate teams (link). 

2024 Spring: Topological quantum matter (graduate course)

• The course will cover the book by D. Vanderbilt "Berry phases in electronic structure theory". Section 2.1.3 is our starting point.

2023 Autumn: Statistical Physics (graduate course)

• It was my second time teaching the course at CAU. We used the textbook by Kardar, the field one, and covered up to Ch5, the perturbative RG. From the electromagnetic theory, the concept of fields is already familiar to us. We extend the usage of classical field to many body systems in condensed matter by coarse-graining.  Once a system Hamiltonian is written in terms of classical fields according to the locality, symmetry, and stability, universal features of many body system begin to appear that can be explicitly checked with the Landau-Ginzburg Hamiltonian. 

• The classical field theory is useful. It provides you how to think of many body system effectively and systematically. It teaches you how the concept of universality appears in nature. Without extra complication by quantum, you can understand how the RG works in practice. 

2023 Autumn: Statistical Physics (undergraduate course)

• How do physicists deal with classical/quantum many body systems? Borrowing the fundamental assumption of statistical mechanics, every micro-state is equally probable for an isolated system. Statistically the most probable macro-state  can be found from the counting of number of micro-states. This makes an explicit bridge between micro- and macro-scopic description of the world. The second half of the textbook by Schroeder is covered. 

• The course covers the black body radiation, the spontaneous emission, Bose-Einstein condensation, collective excitation in solids (phonon, magnon), 1D and 2D Ising model, etc. In my opinion, this course must be taken by every physics major. Currently, it is elective. Quantum thermodynamics, the thermodynamics of active-matter, and the information science are very closely related academic subjects. 

2023 Spring: Thermodynamics

• The first offline class without a face mask. The course is designed for junior physics major students.

• The course was taught up to the van der Waals equation to understand the phase transition between gas and liquid by searching a trajectory in phase space (Temperature  and pressure) minimizing the Gibbs free energy. Near the critical point, we computed a few critical exponents, characterizing the continous phase transition. I think students enjoyed the presentation of different cooling processes: cooling of gases, Helium3 and Helium4, laser cooling, and magnetic cooling. The invention of the cooling processes opened the era of quantum science in early 20th century. The concept of entropy was taught from the two ways: one is from the counting of microstates yielding one macrostates. The other is from the thermodynamic identity, where the first derivative of entropy is related to temperature, pressure, and chemical potential. It is important to understand the connection of microscopic information and macroscopic quantities by entropy as defined in thermodynamics. 

2022 Autumn: Modern physics

• This one semester course was taught based on Feynman lectures. We selected chapters of special relativity in Vol I and Vol II and the front part of the quantum physics in Vol II for the first half and the second of the semester, respectively.

• The volumes are available at https://www.feynmanlectures.caltech.edu, which is being very well managed. 

2022 Summer: quantum computer reading group (QCR)

• We are actively recuiting  readers for quantum computing. Contact me for more information. 

2022 Spring: Topological phases of matter (Graudaute course)

• The textbook written by J. Moore and R. Moessnere is chosen as the main reference of the course. The book itself is not pedagogically written and it is not for people who want to absorb the contents without missing steps in derivations. For the latter purpose and begginers, the book by D. Vanderbilt (2018) is recommended. 

• This course covered the first half of the main textbook which contains more wide range of topics associated with topology in condensed matter physics including topological field theories, disorder, out-of-equilibrium, and quantum computation. 

2022 Spring: Solid state physics

• The first offline course that I taught. 

• The class enjoyed (I believe) the random number generator based oral conversation on various topics including colloquium and course materials. 

2021 Autumn: General Physics II

• The course covered vibration, thermodynamics, electromagnetism, and special relativity. 

• The course began with a question of moving charge and a wire carrying electric current. In the frame of wire, there is a magnetic force acting on the moving charge, while in the frame of the charge there is seemingly no Lorentz force at all. The question is answered after the special relativity was taught. 

2021 Autumn: Statistical physics (Graduate course)

• The course covered the textbook by Kardar "Statistical physics of fields" from chapter1 to chapter8. 

• The central theme is to understand the thermal phase transition, the statistical field and fluctuation, the renormalization group method, the universality, associated critical exponents,  and various prototypical models in condensed matter. 

2021 Summer break: Quantum computation basics, study meeting

• We hold weekly online/offline meetings to follow up classical & quantum information theory and recent developments in quantum algorithms. 

• Contact me (kunx@cau.ac.kr) if you are interested in being a part of our meeting. 

2021 Spring: General Physics I

• The course is divided into three major themes: mechanics, waves, and thermodynamics

• The course was held for the first year chemistry majors. 

• Emphasis was to understand the motion of point masses, then rigid bodies, fluids, and gases. 

2021 Spring: Solid state physics

• I taught solid state physics for one term, using textbook by Steve H. Simon. We covered the book from the front page to the last. 

• Students were divided into 6 or 7 groups. Each group was responsible to hand in one (complete) solution.  Weekly homework covered most of exercises in the book.