Quantum Spin (8) - Stern Gerlach, Measurement, & Entanglement

[Undergraduate Level] - In my final video in my series on quantum spin, I discuss how quantum measurement works, using the Stern Gerlach set up as my basic example. (This video builds heavily off of the last video, in which I discuss particle motion and the influence of magnetic fields.) I then zoom out a bit, and discuss how quantum measurement works in general, and how entanglement is related. It turns out that a quantum measurement will entangle the degree of freedom you are trying to measure with some other degree of freedom. I close out the video by discussing quantum measurement collapse and decoherence. Essentially, after a measurement is performed, the measurement device will become entangled with the surrounding environment, which will prevent you from "seeing" the superposition state of the final entangled measured state. (This is closely related to Schrodinger's cat paradox, which is why you don't see the cat in a superposition of an alive and dead state, just one or the other.)