Past exam of the mathematics course of the University of Cambridge 2022 ii Paper 2 15D b iii Solution Created 2026-09-24 Updated 2026-09-25
There are uncountably many physically distinct one-qubit unitaries. Part (ii) would require an orthogonal program state for every one, whereas a -qubit register has dimension only . This contradiction is the no-programming theorem, so no deterministic gate satisfying (PROG) exists.