Physics 181 explanations, files, and animations

Here we have the explanation and animation files (movies) for the PHYS181 course I taught in the spring of 2012.

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 phys181qmREADME.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).

A Gaussian wave packet bouncing around in an infinite well (particle in a box)
A Gaussian wave packet in a finite well bouncing around
A Gaussian wave packet in a harmonic potential bouncing around. Shows perfect recurrence after one period.
A Gaussian wave packet with a relatively wide initial width evolves in time (shows weak dispersion)
A Gaussian wave packet with a relatively narrow initial width evolves in time (shows strong dispersion)
A Gaussian wave packet is launched at a rectangular barrier and suffers reflection and transmission (shows tunneling).

Matlab codes generating these animations: infinite_well.m , finite_well.m ,  qho.mfree_particle.mtunneling.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 recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).”