PHYS 181

Here we have the explanation and animation files (movies) for the PHYS181 course I taught spring 2009.

First is a simple computation of the single-slit diffraction pattern. The point is to see under what limits the usual diffraction formula holds and how the pattern evolves from diffraction (far-field, narrow slit, etc.) to a geometrical ``shadow'' for a wide slit where diffraction effects are washed out. A PDF file single_slit.pdf has the explanations and figures and the matlab code that does the computations is single_slit.m.

The remainder of this page has the animations for time evolution of wave functions in one dimensions for a few simple cases. See the phys181README.pdf file for details. The actual matlab code I used to generate the movie frames are also provided for your perusal and/or experimentation (the ".m" files).

• phys181README.pdf : PDF file with explanations of movies, physical setup, and what to note.
• infinite_well.mp4 : A Gaussian wave packet bouncing around in an infinite well (particle in a box).
• finite_well.mp4 : A Gaussian wave packet in a finite well bouncing around.
• qho.mp4 : A Gaussian wave packet in a harmonic potential bouncing around; shows perfect recurrence after one period.
• free_particle_sig20.mp4 and free_particle_sig5.mp4 : Two free Gaussian wave packet with different initial widths but same momentum evolving in time (shows dispersion).
• tunneling.mp4 : A Gaussian wave packet is launched at a rectangular barrier and suffers reflection and transmission (tunneling).

Matlab codes generating these animations

• infinite_well.m
• finite_well.m
• qho.m
• free_particle.m
• tunneling.m

This material is based upon work supported by the National Science Foundation under Grants MRSEC DMR-0520495 and DMR-0808665. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).