phy-4600/solutions/chap2/prob2
2016-04-28 16:51:34 -04:00

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S𝓍 ≐ ħ͟⎛0 1⎞
2⎝1 0⎠
Diagonalize the matrix...
First, find the characteristic equation and solve for the eigenvalues.
S𝓍 ≐ ħ͟⎛0 1⎞
2⎝1 0⎠
ħ͟ ⎛-λ 1⎞
2 ⎝ 1 -λ⎠
λ² - ħ²/4 = 0
λ² = ħ²/4
λ = ±ħ/2
So the eigenvalues are those expected for the measurement of a spin-1/2 component.
The eigenvalue equations are
S𝓍❙Ψ❭ = λ❙Ψ❭
which is represented by
ħ͟⎛0 1⎞⎛a⎞ = λ⎛a⎞
2⎝1 0⎠⎝b⎠ ⎝b⎠