Hamiltonian mechanics Updated +Created
Equivalent to Lagrangian mechanics but formulated in a different way.
TODO understand original historical motivation, www.youtube.com/watch?v=SZXHoWwBcDc says it is from optics.
Intuitively, the Hamiltonian is the total energy of the system in terms of arbitrary parameters, a bit like Lagrangian mechanics.
Photonics Updated +Created
The science and engineering of photons!
A bit more photon-specific than optics.