 Solution

ID: past-exam-of-the-computer-science-course-of-the-university-of-oxford/2020/quantum-information/1/b/i/solution

Choose $∣ ψ ⟩ = ∣0 ⟩$ . Since

∣0 ⟩ = (∣ ϕ_{0} ⟩ + ∣ ϕ_{2} ⟩) / 2

(1/ 2, 0, 1/ 2)

. Their squared moduli give

(1/2, 0, 1/2)

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