 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2021/ii/paper-4/34b/a/solution

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

E_{0} (k) = ℏ^{2} k^{2} / (2 m)

k = 2 πn / L

⟨ k ∣ U ∣ k' ⟩ = U_{l}

when

k' - k = 2 π l / a

, and zero otherwise.

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