are the periodic boundary conditions for the crystal

is an approximation to first order for light-matter interaction

is related to the separation of nuclei and electrons motions

is the birthday of von Kármán

optical spectroscopy

photo-emission spectroscopy

inelastic X-ray scattering

electron energy loss spectroscopy

Because it efficiently accelerates particles.

Because it emits high-energy X-rays

Because it works at high energy

Because it produces high-energy electron beam

a tough but solvable problem (in the non relativistic case)

is a polinomially difficult problem (hard to solve)

is an exponentially difficult problem (almost impossible to solve)

ok

f(x) = x²

∫ f(x) dx

Area = ∫ₐ^b h(x) dx

whatever non linear function

illustrates the energy of the electrons

gives insights about the symmetry of the system

comes from the single-particle wavefunctions of the system

gives the optical spectrum

is an approximation to separate nuclei and electrons

is a way to write the periodic boundary conditions

is an exact condition for electron and nuclei

formula solves in principle the many-body problem

more complicate arguments

advanced physics (not suitable for dummies)

relativistic, quantistic, etc.

we do research (real stuff) with it.

a swearing word in english

World War I Marshal Ferdinand Fock

Vladimir Fock, developer of the antisymmetric part in the one-particle Hartree equations.

Carin Fock, the first wife of Hermann Göring