R Allan Barker          science | technology | history | philosophy + curiosity
Last update December 5, 2013 Contact me

What do electrons do, really?

Perhaps one of the best clues to how electrons might behave at the quantum level comes from the following video. The video shows a single continuous simulation using wave equations that describe electrons and electromagnetic waves of light. Everything shown in the video is output directly from the simulation and nothing has been drawn or illustrated. The music is Tchaikovsky's Waltz from Serenade for Strings and describes the electron's motions amazingly well. Please listen. The horizontal scale for light waves is compressed to show the individual waves. The frequency is correct. In order, the video shows:
  1. A ground state electron promoted to an excited state by adsorbing a quantum of green light with an energy of 2.05 eV.
  2. An excited state electron promoted to a higher excited state by adsorbing a quantum of red light with 1.82 eV energy.
  3. A ground state electron cannot be promoted to the first excited state using red light.
  4. Spontaneous emission of energy from an excited state electron that  modulates the EM field at the frequency of green light. 
  5. Green light stimulated emission of  a quantum of green light from an excited state electron, the process responsible for lasers.
  6. At the end, the nuclear electrostatic potential is turned off in the simulation and the electron begins to dissipate.

The equation used for the simulation couples the time dependent Schrodinger equation with a scalar electromagnetic potential function A(r,t) from Maxwell's equations. The Cd time derivative term is responsible for spontaneous emission.
High speed replay

Atomic electrons can move incredibly fast. This high speed playback gives a slightly different sense of movement.


After reading many descriptions of mysterious electrons, quantum jumps and photons, it's surprising to learn the concepts have always been controversial. Here's what Heisenberg said about Schrodinger's work.

The more I think about the physical part of the Schrödinger theory, the more detestable I find it. What Schrödinger writes about visualization makes scarcely any sense, in other words I think it is shit. The greatest result of his theory is the calculation of matrix elements. Heisenberg to Pauli, 1926.

Comments are welcome. Please send me an email here, and I will post your comments below.

Letter from Heisenberg to Pauli, 8 June 1926, quoted in Walter Moore, Schrödinger: Life and Thought
(Cambridge University Press, Cambridge, UK, 1989) page 221.