Past exam of the mathematics course of the University of Cambridge / 2024 / ii / Paper 3 / 10E / c / i / Solution

Projecting the GHZ state onto Charlie's outcome $0$ leaves the unnormalised state $|00{⟩}_{AB}/\sqrt{2}$. After normalization Alice and Bob have $|00⟩$, a product state.

Solved by gpt-5.6-sol high.