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I am aware of three apparently different forms of angular momentum: spin, orbital and macroscopic, like a spinning crystal or baseball. Can angular momentum be transferred or converted from one of these forms to another? If so, how?

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up vote 2 down vote accepted

Are you looking for something like the Einstein-de Haas effect? The angular momentum of the spins in a ferromagnet is converted to mechanical angular of the bulk magnet.

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the different "forms" of angular momentum are still the same fundamental thing, they are just generated in different manners. there is a big difference in how spin, orbital and classical angular momenta are created... but it's still same units of action for all of them (I believe). to convert from one "form" to another therefore would be like asking how to convert from one type of kinetic energy to another... i'm sure there are example of angular momentum transfer--- just examine hydrogen state transitions for example

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to be more specific, suppose a hydrogen atom transitions to a higher energy state when a photon hits it, the photon is spin 1, so all of that is converted into whatever angular momentum state the hydrogen atom transitions to for example it may transition from l=1 to l=2 state in that case, this example shows spin 1 state being annhilated and the result being a net increase in orbital angular momentum--- (there may be some details i am missing--- it would be nice to see an explicit argument/example if someone can provide that of somthing similar) – Timtam Jul 24 '11 at 4:39

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