# Student Colloquium, Jeppe Thøis Madsen: Schrödinger’s path from optics to an equation with an imaginary unit

*Supervisor: Brian Julsgaard*

In 1913, the Bohr model was introduced: The first quantized model of the atom. In 1924, de Broglie associated a wavelength to all particles. At the time, some physicists e.g. Bohr found the description of the world as quantized contradictory to it as waves. Waves were a theory of continuum. How could they account for phenomena that are discrete?

Schrödinger was searching for an answer to this question. Could waves account for discrete phenomena? He looked to the field of optics where the geometrical ray description of light had long been known to be incomplete - incapable of describing phenomena as diffraction and refraction without considering waves. Was this concept more general? Could the wave behavior of particles result in quantization? The answers to these questions were given in his 1926 publication Quantisierung als Eigenwertproblem (Quantization as an Eigenvalue Problem).

This colloquium will retrace the steps of Schrödinger from optics to his time-independent wave equation.