1. Bell 态：|Φ⁺⟩ = (|00⟩+|11⟩)/√2（三行代码的制备目标）
2. 演化链：|00⟩ →(H⊗I) (|00⟩+|10⟩)/√2 →(CNOT) |Φ⁺⟩
3. 测量概率：P(00) = P(11) = 1/2，P(01) = P(10) = 0
4. 期望与涨落：E[n_x] = Np，σ = √(Np(1−p))；N = 1024、p = 1/2 → σ = 16
5. 频率估计：p̂(x) = n_x/N（counts → probabilities 的换算式）
6. 键换算：整数 k = Σᵢ bᵢ·2ⁱ ↔ 二进制串