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| classes:2009:fall:phys4101.001:q_a_1120 [2009/11/20 11:01] – johnson | classes:2009:fall:phys4101.001:q_a_1120 [2009/12/19 17:15] (current) – x500_sohnx020 | ||
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| ====Daniel Faraday 11/20 1030am==== | ====Daniel Faraday 11/20 1030am==== | ||
| I am still confused about all the different, equivalent(? | I am still confused about all the different, equivalent(? | ||
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| + | ===Devlin=== | ||
| + | I'm confused by this as well. | ||
| ===David Hilbert' | ===David Hilbert' | ||
| Do you mean the spinors or the | s m> , | s (m +1)> business? Because I was pretty lost when writing things like S | s m > on what the ket means, but if you go back to chapter 3 it says that any ket is a vector in Hilbert (!) space, so it must correspond to a particle having a generic spin s and associated m. When you operate on it with the different S operators, the eigenvalues are your observable spin states. If you look in the book Griffiths never actually writes down explicitly what any operator or state is for spin, because you can use commutation relations to find eigenvalues instead of solving a more difficult problem involving operators and states. | Do you mean the spinors or the | s m> , | s (m +1)> business? Because I was pretty lost when writing things like S | s m > on what the ket means, but if you go back to chapter 3 it says that any ket is a vector in Hilbert (!) space, so it must correspond to a particle having a generic spin s and associated m. When you operate on it with the different S operators, the eigenvalues are your observable spin states. If you look in the book Griffiths never actually writes down explicitly what any operator or state is for spin, because you can use commutation relations to find eigenvalues instead of solving a more difficult problem involving operators and states. | ||
| + | ==Pluto 4ever 11/20 6:30PM== | ||
| + | I was also confused about this as well. Thanks for the input. Now maybe I'll be able to do problem 18 in the homework. | ||
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| + | ====Jake22 11/22 8:10pm==== | ||
| + | We have seen examples of the nature of coupling between spin and electromagnetic interactions (Stern-Gerlach). For example we know that any charged particle with spin also has a magnetic moment. What can we say about the nature of coupling between spin and strong or weak interactions? | ||
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| + | ====Blackbox 11/23 11am ==== | ||
| + | Can you explain the meaning of (1) and (2) of < | ||
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| + | ===Jake22 11/23 3:50pm === | ||
| + | They are referring to particles 1 and 2, respectively. | ||
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| + | ====ice IX 11/23 18:44==== | ||
| + | On page 182 Griffiths discusses the Stern-Gerlach experiment, and uses the specific case of the silver atom to show that the net spin is s=1/2. This net spin comes from the unpaired valence electron. What happens when the valence contains a pair (or pairs) of electrons, but no unpaired electrons? Will there be no beam splitting in such a situation? | ||
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| + | ====Jake22 11/30 18:34==== | ||
| + | In the Stern-Gerlach experiment, why must we have a beam of relatively heavy atoms in order to construct localized wave packets and treat the motion in terms of classical particle trajectories? | ||
| + | === Blackbox 19:10 === | ||
| + | The experiment can be used to demonstrate that electrons and atoms have intrinsically quantum properties, and how measurement in quantum mechanics affects the system being measured. I think that the purpose of relatively heavy atoms are to prevent the gross deflection of the orbit of a charged particle in a magnetic field and bring out the spin-dependent effect. | ||
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