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mtd
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Homework Statement
A spin-1/2 system in the state [itex] \left|ψ\right\rangle = \left|0.5, z\right\rangle[/itex] of the [itex]S_{z}[/itex] spin operator has eigenvalue [itex]s = +\hbar/2[/itex]. Find the expectation values of the [itex]S_{z}[/itex] and [itex]S_{x}[/itex] operators.
Homework Equations
[itex]\left\langle S_{x,z}\right\rangle = \left\langle ψ \right| S_{x,z}\left|ψ\right\rangle[/itex]
The Attempt at a Solution
Multiplied out above equations to find [itex]\hbar z/2[/itex] and [itex]\hbar (0.25 - z^{2})/2[/itex] for the x and z directions, respectively. I assume [itex]z[/itex] is just "some variable" - is it safe to normalize the eigenstate and set z equal to root 0.75?
Homework Statement
Find the probability of measuring [itex]\hbar /2[/itex] in a measurement of [itex]S_{x}[/itex] in the same system.
Homework Equations
The probability of measuring the eigenvalue [itex]a_{n}[/itex] in a measurement of the observable [itex]A[/itex] is [itex]P \left( a_{n} \right) = \left| \left\langle b_{n} |ψ \right\rangle \right| ^{2}[/itex] where [itex]\left|b_{n}\right\rangle[/itex] is the normalised eigenvector of [itex]A[/itex] corresponding the the eigenvalue
The Attempt at a Solution
I believe this should just be the eigenvalue squared i.e. [itex]\hbar ^{2}/4[/itex], but I'm not sure if or why this is the case.
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