This week will expand on the concept of Quantum waves and the Schrödinger approach to wave solutions.
 Group and Phase Velocity
A single wave is easy to visualize as sinusoidal
function through space. Once the concept of superposition of waves is introduced
a few more visual concepts are needed. Specifically the introduction of
group and phase velocity. View this applet and read the explanation.

1. What is the effect of setting the group velocity to a value greater then one?
2. What is the effect of setting the group velocity to a value less then one?
3. In your own words what is the difference between the group and phase velocity?

Bound States
For
a particle trapped in a potential the Schrödinger equation only allows discrete
solutions. The first example is a particle trapped in an infinite well.
Like a string attached to two concrete walls only integer and half integer
wavelengths are stable. This applet allows you to look at the wave functions
for an infinite well and other non-infinite potentials. Read how to operate
the applet before trying to understand it.

1. For the infinite well what do you notice about the wave function as you increase the energy level.
2. Double click on an energy
level with the phasor circles on the bottom. Now add an additional energy
level by single clicking on a different energy level. What do you notice
about the total wave function? Is it static? Why is this true? (view
the website on superposition of waves from week 4 for help)
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