Experiment 7

In this experiment you will examine the strange phenomenon of quantum interference, and you will also further examine the affect of measurement on the quantum state of a particle. In this experiment the electrons coming out of the Electron Gun are all in the z-up state (i.e. they will all have spin up if measured along the z-axis). The beam is first sent through an x-analyzer. Both of the beams emerging form the x-analyzer are then recombined and sent into the same z-analyzer.

Click the green arrow next to Experiment 7 in the navigation menu to run the simulation. Note that there is a new control in this simulation. This control is called the Watch Button and it determines whether or not you have some way of determining which path the electron followed after leaving the x-analyzer. If the Watch Button is "on" (it says "Watch"), then you are able to extract this "which-path" information from the experiment. If the Watch Button is "off" (the word "Watch" is marked out) then you have set up the experiment so that there is no way to extract this "which-path" information. Click the Watch Button to see how you can change it from "off" to "on", and vice versa.