witzvo comments on Ask an experimental physicist - Less Wrong

35 Post author: RolfAndreassen 08 June 2012 11:43PM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (294)

You are viewing a single comment's thread. Show more comments above.

Comment author: witzvo 10 June 2012 08:31:55PM *  1 point [-]

describe the process in two sentences.

Well, that's helpful, but of course, I don't know how you know that the electrons have such and such spin or what superposition has to do with anything. Neither could I reproduce the experiment (someone competent could, I'm sure). Maybe there was a first experiment where they did this and spin was discovered?

EDIT: anyway, I'm tapping out of here and will check out the sequences. Thanks All

Comment author: Dreaded_Anomaly 10 June 2012 10:27:03PM 4 points [-]

I don't know how you know that the electrons have such and such spin

Electrons have both electric charge and spin (which is a form of angular momentum), and in combination, these two properties create an intrinsic magnetic moment. A magnetic field exerts torque on anything with a magnetic moment, which causes the electron to precess if it is subjected to such a field. Because spin is quantized and has only two possible values for electrons (+1/2 or -1/2), they will only precess in two discrete ways. This can be used to separate the electrons by their spin values. The first experiment to do this was the Stern-Gerlach experiment, a classic in the early development of QM, and often considered to be the discovery of spin.

Comment author: witzvo 10 June 2012 10:58:58PM 1 point [-]

Thanks.