 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2024/ii/paper-3/33b/a/ii/solution

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

Taking a matrix element of

[O, J_{3}] = 0

gives

ℏ (m^{'} - m) ⟨ j, m ∣ O ∣ j^{'}, m^{'} ⟩ = 0.

Thus the matrix element vanishes unless $m = m^{'}$ .

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