小结、作业与预告

① y_pred = ⟨0|U†(x,θ)·M·U(x,θ)|0⟩(QNN 前馈)

② ∂⟨M⟩/∂θ_k = ½(⟨M⟩₊ − ⟨M⟩₋),采样点 θ_k ± π/2(参数平移)

③ Pr(0ⁿ) = |⟨φ(x)|φ(x′)⟩|²(碰撞测量);采样 O(log(1/δ)/ε²)

④ f_θ(x) = ⟨φ′(x)|·M·|φ′(x)⟩,|φ′(x)⟩ = U_φ(x)·W|0⟩(QNN = 核模型)

⑤ Var[∂C/∂θⱼ] ∼ 2⁻ⁿ(高原定义);2-设计界 Var ≲ poly(n)/4ⁿ

⑥ C_L ≤ C_G ≤ n·C_L;Var[∂C_L] ∼ 1/poly(n)(局部代价)

⑦ Var ≲ η^(2L)·Var₀ + O((1−η^L)²/2ⁿ),η = e^(−ε)(噪声高原)

⑧ E[|⟨ψ|φ⟩|²] = 2⁻ⁿ(集中测度统一式)

类型summary-homework(公式清单)