 Solution

ID: past-exam-of-the-computer-science-course-of-the-university-of-oxford/2020/quantum-information/2/b/i/solution

∣ Ψ_{1} ⟩ = (\frac{∣0 ⟩ - ∣1 ⟩}{2}) \otimes (\frac{∣0 ⟩ - ∣1 ⟩}{2}) = ∣ - ⟩ \otimes ∣ - ⟩ .

Therefore the first state is a product state, not entangled. Both factors have unit norm, so this factorization also checks normalization.

 New to topics? Read the docs here!