Quantum Computing, Superposition, Entanglement, Wave Function, Artificial Intelligence.
|ψ2⟩ (written as |q1⟩, the target qubit, in the code) using a controlled NOT (CNOT) gate. If the control qubit |ψ1⟩ is in |0⟩ (i.e., |ψ1⟩ = |q0⟩ = |0⟩), by definition, the target qubit remains unchanged. Therefore, the output would simply be |ψ2⟩ = b(α2|0⟩ + β2|1⟩), in the single-qubit expression.