Below are some notes I wrote on various subjects, mostly when I was learning or teaching them. They are not tied to any active research subjects.
Notes on an informal proof of the prime number theorem
Notes (in collaboration with ChatGPT!) on a combinatorics identity and relation to the quantum cluster expansion for an ideal quantum gas
Notes (handwritten) on Poisson brackets nad Wess-Zumino-Witten term in path integral
Notes (handwritten) on 2+1d TQFT, solvable models for topological order, and SPT's (resolving a minor error in the literature)
Notes (handwritten) on Dijkgraaf -Witten gauge theory
Notes on superfluid density, Goldstones and Ward identity
Notes on Wannierizable bands supporting gapless edge states
Notes on poor-man's scaling in Kondo problem
Notes on the Luttinger theorem
Notes on photons as Goldstone modes of a spontaneous broken 1-form U(1) symmetry
Notes on fermionic operators in the toric code
Notes on a neat relation between the spectral function and density of states in superconductors from quantum-critical fluctuation
Notes on T-duality and bosonization
Notes on minimal models in CFT
Notes on Legendre transform in classical mechanics and in thermodynamics
Notes (handwritten) on spin glass