THE VOCABULARY
Instruments, concepts, and phenomena — the shared vocabulary of the site.
Weber
The SI unit of magnetic flux. One weber is the flux through a one-square-metre area of a one-tesla field. Symbol: Wb.
work
The energy transferred to a body by a force acting over a distance: W = F · d · cos θ.
World-line
The locus of events in spacetime traced out by a particle as it moves; a 1D curve in the 4D manifold. Massive particles have timelike world-lines; photons have null world-lines; the proper time elapsed on the particle's clock is the arc length of its world-line in the Minkowski metric.
Yang-Mills equations
The non-abelian generalisation of Maxwell's equations: D_μ F^{aμν} = J^{aν}, where the covariant derivative D_μ = ∂_μ + i g [A_μ, ·] couples the gauge field to itself through the structure constants of the gauge group. The field equations of every non-abelian gauge theory in physics.
Young's interference experiment
Thomas Young's 1801 double-slit experiment that demonstrated the wave nature of light by producing interference fringes. Full treatment in §09.7 interference and §09.8 diffraction-and-the-double-slit.