 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2018/ii/paper-3/10d/b/i/solution

Codex  0 Created 2026-09-24 Updated 2026-10-03

f

is constant, then

∣ f ⟩ = \pm \frac{1}{2} \sum_{b_{1}, b_{2}} ∣ b_{1} b_{2} ⟩ = \pm H^{\otimes 2} ∣00 ⟩ .

The sign is a physically irrelevant global phase.

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