Physics Study Notes & Write-ups
Informal study notes, derivations, and course write-ups from my undergraduate studies at Tsinghua. Shared for personal reference and discussion; they may contain typos or inaccuracies.
The "What is" Series
What is Electric Charge?
June 2026An intuitive look at electric charge, Coulomb's law, and gauge invariance. Available in English and Chinese.
Course Write-ups & Topic Summaries
Canonical vs Path Integral Quantization
Spring 2024Derivations comparing canonical operator quantization with Feynman's path integral formulation in non-relativistic quantum mechanics.
Black Hole Thermodynamics
Autumn 2024A brief survey of the four laws of black hole mechanics, Bekenstein–Hawking entropy, and Hawking radiation.
Quantum Harmonic Ensemble
Spring 2025Deriving the partition function for a canonical ensemble of quantum harmonic oscillators across energy, coordinate, and momentum representations.
Neutrino Mass & Oscillations
Spring 2025Review of experimental evidence for neutrino flavour oscillations (Super-K, SNO), mass mechanisms, and PMNS mixing.
Action Principle in Electrodynamics
Summer 2025Deriving Maxwell’s equations in vacuum from the relativistic Lagrangian density, gauge invariance, and Noether currents.
Polarised Deuteron Breakup
Summer 2025Report on polarised deuteron scattering observables and polarimeter design for probing nuclear symmetry energy (undergraduate research training).
Complex Scalar Klein-Gordon Field
Summer 2025Derivation of canonical momenta, quantization commutation relations, and global U(1) Noether symmetry for a complex Klein–Gordon field.