Angular momentum state of the form |ψ⟩ = |ℓ,0>.
Use this state in determining the expectation values of Lx, Lx^2, and determine σLx for this state. Discuss your result, especially the ℓ=0 case.
Hint: Use Lx = (L+ + L-)/2 and Ly = -i(L+ - L-)/2.
Remember also that L±L∓ = L^2 - Lz^2 ± ħLz.