The foundational natural science: matter, energy, space, time, and their interactions, from the subatomic to the cosmological. Sister library to Chemistry/, Biology/, MaterialsScience/, and ClimateScience/; sits beneath the mathematics of Math-and-Compute/Math/ and above the applied treatments in Engineering-and-Robotics/Engineering/. This library carries the physics foundations; where a topic also has an engineering or chemistry home, the foundational physics lives here and the applied treatment is cross-linked, not duplicated.
Status: Tier 1 complete across all major disciplines (18 notes, authored 2026-06-01).
Units: SI primary; natural units (\hbar = c = 1) noted where conventional in QFT/particle physics; astronomical units (M_\odot, pc, eV) where idiomatic.
Math conventions: equations in KaTeX ($...$ / $$...$$); LaTeX commands throughout (no raw Unicode inside math).
numerical methods, Monte Carlo, molecular dynamics, DFT, lattice QCD, HPC
Coverage notes
Acoustics is folded into waves-optics-and-acoustics; optics/photonics foundations live there too, with the device/engineering treatment in photonics.
Mathematical physics (the methods themselves — group theory, differential geometry, functional analysis, PDE theory) is covered in the Math-and-Compute/Math/ library and cross-linked from the relevant notes rather than duplicated here.
Medical physics, econophysics, atmospheric physics are applied/interdisciplinary and live with their host domains (nuclear-engineering, Society/, ClimateScience); pointers appear from the relevant Tier-1 notes.
Adjacent libraries
physical-chemistry — thermodynamics & quantum chemistry from the substance angle