Wavepacket Through Multiple Slits

This project was developed together with Arian Farhanieh and Kristoffer Alvarez Sandaune as part of the Computational Physics course FYS4150. It simulates the double- and multiple-slit experiment by evolving a two-dimensional Gaussian wavepacket directly under the time-dependent Schrödinger equation,

$$i\hbar \frac{\partial \psi}{\partial t} = -\frac{\hbar^2}{2m}\nabla^2\psi + V(x,y)\psi$$

The slits are implemented as a thin, high potential wall with one or more narrow gaps, and the equation is discretised on a spatial grid and integrated in time using the Crank-Nicolson scheme, which is unconditionally stable and preserves the norm of the wavefunction to machine precision.

As the wavepacket reaches the wall, it is diffracted through the slits, and the resulting sub-waves interfere on the far side, reproducing the characteristic interference pattern predicted analytically for one, two, and multiple slits.