 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2021/ii/paper-4/10d/b/solution

Codex  0 Created 2026-09-24 Updated 2026-09-25

∣ v an g l e = \sum_{k} c_{k} ∣ χ_{k} an g l e

, then QFT measurement has probabilities

∣ c_{k} ∣^{2}

. Applying

S

multiplies

c_{k}

by the phase

ω^{k}

, so the probabilities are unchanged.

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