- #1
JeremyEbert
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I can't seem to reconcile a part of the vector model of spin and some of its operators.
to quote wiki just above the "Bohr model" section:
http://en.wikipedia.org/wiki/Vector_model_of_the_atom#Mathematical_background_of_angular_momenta
"2.The magnitude of the vectors must be constant (for a specified state corresponding to the quantum number),
so the two indeterminate components of each of the vectors must be confined to a circle,
in such a way that the measurable and un-measurable components (at an instant of time)
allow the magnitudes to be constructed correctly, for all possible indeterminate components."
I would assume pythagorean theorem holds true and "the two indeterminate components (S_x & S_y)
of each of the vectors must be confined to a circle" of radius r:
magnitude = sqrt(s(s+1))
r = sqrt(s(s+1) - m^2)
however the operators are defined as:
S+ = sqrt(s(s+1) - m(m+1))
S- = sqrt(s(s+1) - m(m-1))
http://en.wikipedia.org/wiki/Spin_(physics)#Spin_operator
http://en.wikipedia.org/wiki/Anti-symmetric_operator#Spin
I must be missing something obvious. Please help.
A visual of spin 5/2 with some notes:
http://dl.dropbox.com/u/13155084/SPIN/SPIN-5-2-ladder-crop.png
to quote wiki just above the "Bohr model" section:
http://en.wikipedia.org/wiki/Vector_model_of_the_atom#Mathematical_background_of_angular_momenta
"2.The magnitude of the vectors must be constant (for a specified state corresponding to the quantum number),
so the two indeterminate components of each of the vectors must be confined to a circle,
in such a way that the measurable and un-measurable components (at an instant of time)
allow the magnitudes to be constructed correctly, for all possible indeterminate components."
I would assume pythagorean theorem holds true and "the two indeterminate components (S_x & S_y)
of each of the vectors must be confined to a circle" of radius r:
magnitude = sqrt(s(s+1))
r = sqrt(s(s+1) - m^2)
however the operators are defined as:
S+ = sqrt(s(s+1) - m(m+1))
S- = sqrt(s(s+1) - m(m-1))
http://en.wikipedia.org/wiki/Spin_(physics)#Spin_operator
http://en.wikipedia.org/wiki/Anti-symmetric_operator#Spin
I must be missing something obvious. Please help.
A visual of spin 5/2 with some notes:
http://dl.dropbox.com/u/13155084/SPIN/SPIN-5-2-ladder-crop.png
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