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MIPRE.Background.Repetition.CommutingRepetition.OTQCS.Assembly

Transport along a tracial extension #

theorem CommutingRepetition.TracialExtension.tracialPairLaw_map {N : StdTracialAlgebra} (ext : TracialExtension N) {S T A B : Type} (u : S → T → N.H) (E : S → A → N.A) (F : T → B → N.A) (s : S) (t : T) (a : A) (b : B) :
tracialPairLaw ext.N' (fun (s : S) (t : T) => ext.U (u s t)) (fun (s : S) (a : A) => ext.emb (E s a)) (fun (t : T) (b : B) => ext.emb (F t b)) s t a b = tracialPairLaw N u E F s t a b

The pair law is invariant under the spatial extension: U intertwines the left and right actions and preserves inner products.

theorem CommutingRepetition.TracialExtension.piAlignment_map {N : StdTracialAlgebra} (ext : TracialExtension N) {S T : Type} [Fintype S] [Fintype T] (π : S → T → ℝ) (u : S → T → N.H) (xv : S → N.H) (yv : T → N.H) :
(piAlignment π (fun (s : S) (t : T) => ext.U (u s t)) (fun (s : S) => ext.U (xv s)) fun (t : T) => ext.U (yv t)) = piAlignment π u xv yv

The alignment defect is invariant under the isometry U.

theorem CommutingRepetition.TracialExtension.emb_sum_eq_one {N : StdTracialAlgebra} (ext : TracialExtension N) {A : Type u_1} [Fintype A] (E : A → N.A) (hE : ∑ a : A, E a = 1) :
∑ a : A, ext.emb (E a) = 1

ℓ¹ toolkit #

theorem CommutingRepetition.l1_le_two {A : Type u_1} {B : Type u_2} [Fintype A] [Fintype B] (p q : A → B → ℝ) (hp : ∀ (a : A) (b : B), 0 ≤ p a b) (hq : ∀ (a : A) (b : B), 0 ≤ q a b) (hpsum : ∑ a : A, ∑ b : B, p a b = 1) (hqsum : ∑ a : A, ∑ b : B, q a b = 1) :
∑ a : A, ∑ b : B, |p a b - q a b| ≤ 2

Two probability laws on a finite product are at unhalved ℓ¹ distance at most 2.

theorem CommutingRepetition.l1_le_of_decomposition {A : Type u_1} {B : Type u_2} [Fintype A] [Fintype B] (qhat qz q r : A → B → ℝ) (cm : ℝ) (hcm0 : 0 ≤ cm) (hr : ∀ (a : A) (b : B), 0 ≤ r a b) (hrsum : ∑ a : A, ∑ b : B, r a b = 1 - cm) (hq : ∀ (a : A) (b : B), 0 ≤ q a b) (hqsum : ∑ a : A, ∑ b : B, q a b = 1) (hdec : ∀ (a : A) (b : B), qhat a b = cm * qz a b + r a b) :
∑ a : A, ∑ b : B, |qhat a b - q a b| ≤ ∑ a : A, ∑ b : B, |qz a b - q a b| + 2 * (1 - cm)

ℓ¹ conversion of a branch decomposition q̂ = cm · q_z + r with nonnegative remainder of mass 1 − cm against a probability law q: ‖q̂ − q‖₁ ≤ ‖q_z − q‖₁ + 2(1 − cm) (06_otqcs.tex, the display deriving eq otqcs-main: "on a bad branch the unhalved ℓ¹ cost is at most 2").

theorem CommutingRepetition.sum_abs_tracialPairLaw_sub_le (N : StdTracialAlgebra) {S T A B : Type} [Fintype A] [Fintype B] (E : S → A → N.A) (F : T → B → N.A) (hE : ∀ (s : S) (a : A), IsPosElem (E s a)) (hF : ∀ (t : T) (b : B), IsPosElem (F t b)) (hEs : ∀ (s : S), ∑ a : A, E s a = 1) (hFs : ∀ (t : T), ∑ b : B, F t b = 1) (s : S) (t : T) {z w : N.H} (hz : ‖z‖ = 1) (hw : ‖w‖ = 1) :
∑ a : A, ∑ b : B, |tracialPairLaw N (fun (x : S) (x_1 : T) => z) E F s t a b - tracialPairLaw N (fun (x : S) (x_1 : T) => w) E F s t a b| ≤ 2 * ‖z - w‖

Vector-to-ℓ¹ for pair laws (06_otqcs.tex, eq vector-to-l1): two unit vectors' pair laws under one pair of full POVMs differ in unhalved ℓ¹ by at most 2‖z − w‖₂ — the ℓ¹-POVM estimate sum_abs_re_inner_effect_sub_le applied to the commuting product effects L(A_s^a) R(B_t^b).

The finite bad bound at the chosen trial count #

theorem CommutingRepetition.commonMass_nonneg (a b c Z : ℝ) (R : ℕ) (hZ : 0 < Z) (hc : 0 ≤ c) (hle : a + b - c ≤ Z) :
0 ≤ commonMass a b c Z R
theorem CommutingRepetition.two_exp_ceil_le (Z ξ : ℝ) (hZ : 0 < Z) (hξ : 0 < ξ) :
2 * Real.exp (-↑⌈2 * Z * Real.log (2 / ξ ^ 2)⌉₊ / (2 * Z)) ≤ ξ ^ 2

The trial count R = ⌈2 Z log(2/ξ²)⌉ makes the exhaustion tail 2 e^{−R/(2Z)} ≤ ξ² (06_otqcs.tex, eq R-choice).

theorem CommutingRepetition.one_sub_commonMass_le (a b c Z ξ : ℝ) (hZ : 0 < Z) (hξ : 0 < ξ) (ha : 1 / 2 ≤ a) (hb : 1 / 2 ≤ b) (hc : 0 ≤ c) (hca : c ≤ a) (hcb : c ≤ b) (hle : a + b - c ≤ Z) :
1 - commonMass a b c Z ⌈2 * Z * Real.log (2 / ξ ^ 2)⌉₊ ≤ 2 * (a + b - 2 * c) + ξ ^ 2

1 − cm ≤ 2Γ + ξ² at R = ⌈2 Z log(2/ξ²)⌉ (eq finite-bad + eq R-choice).

The selected-state chain (eq selected-state-preopt) #

theorem CommutingRepetition.selSharp_normSq {N : StdTracialAlgebra} {y : N.H} (dB : SpectralData N y) {m : ℕ} (B : Fin m → Set ℝ) (t : Fin m → ℝ) (hB : IsBandFamily B t) :
‖N.ι (selSharp dB B t)‖ ^ 2 = pairMassB dB B t

‖k♯‖₂² = b (06_otqcs.tex, eq rounded-y: the normalization of ỹ).

theorem CommutingRepetition.selSharp_norm {N : StdTracialAlgebra} {y : N.H} (dB : SpectralData N y) {m : ℕ} (B : Fin m → Set ℝ) (t : Fin m → ℝ) (hB : IsBandFamily B t) :
‖N.ι (selSharp dB B t)‖ = √(pairMassB dB B t)
theorem CommutingRepetition.selYTilde_sub_le {N : StdTracialAlgebra} {y : N.H} (dB : SpectralData N y) {m : ℕ} (B : Fin m → Set ℝ) (t : Fin m → ℝ) (hB : IsBandFamily B t) (hy : ‖y‖ = 1) (hb : 0 < pairMassB dB B t) :
‖selYTilde dB B t - y‖ ≤ 2 * ‖N.ι (selSharp dB B t) - dB.hvec‖

The normalization inequality for the rounded polar vector: ‖ỹ_t − y_t‖₂ ≤ 2 ‖k_t^♯ − k_t‖₂ (06_otqcs.tex, eq normalization-inequality applied to ỹ = b^{−1/2} k♯ v, y = k v, with v a right isometry on the relevant vectors — Rop_v_norm).

theorem CommutingRepetition.hvec_sub_selCutVec_le {N : StdTracialAlgebra} {y : N.H} (dB : SpectralData N y) {m : ℕ} (B : Fin m → Set ℝ) (t : Fin m → ℝ) (hB : IsBandFamily B t) (hy : ‖y‖ = 1) {L H ρ : ℝ} (hL : 0 < L) (hLH : L < H) (hU : ⋃ (j : Fin m), B j = Set.Icc L H) (htail : ∫ (b : ℝ) in Set.Ioi H, b ^ 2 ∂dB.μ ≤ ρ) :
‖dB.hvec - selCutVec dB B‖ ≤ √(ρ + L ^ 2)

‖k − k^{cut}‖₂ ≤ √(ρ + L²) when the bands cover [L, H] and the high tail beyond H is at most ρ (06_otqcs.tex, eq rounding-tails).

theorem CommutingRepetition.selState_sub_le {N : StdTracialAlgebra} {x y : N.H} (dA : SpectralData N x) (dB : SpectralData N y) (Jd : JointSpectralData dA dB) {m : ℕ} (B : Fin m → Set ℝ) (t : Fin m → ℝ) (hB : IsBandFamily B t) (hy : ‖y‖ = 1) (ha : 1 / 2 ≤ pairMassA dA B t) (hb : 1 / 2 ≤ pairMassB dB B t) (r : ℝ) (hr : 1 ≤ r) (hband : ∀ (j : Fin m), B j ⊆ Set.Icc (t j / r) (t j)) (κ : ℝ) (hcut : ‖dB.hvec - selCutVec dB B‖ ≤ κ) (u : N.H) :
‖selState dA dB Jd B t - u‖ ≤ 2 * √(pairMassA dA B t + pairMassB dB B t - 2 * pairCross dA dB Jd B t) + 2 * (r - 1 + κ) + ‖y - u‖

The selected-state chain (06_otqcs.tex, eq selected-state-preopt): ‖z_{st} − u_{st}‖₂ ≤ 2√Γ_{st} + 2((r − 1) + κ) + ‖y_t − u_{st}‖₂, where r − 1 = α bounds the rounding ‖k♯ − k^{cut}‖ and κ the cut ‖k^{cut} − k‖.

Hypotheses of the grid slab read off a joint spectral package #

theorem CommutingRepetition.JointSpectralData.ae_nonneg {N : StdTracialAlgebra} {x y : N.H} {dA : SpectralData N x} {dB : SpectralData N y} (Jd : JointSpectralData dA dB) :
∀ᵐ (p : ℝ × ℝ) ∂Jd.ν, 0 ≤ p.1 ∧ 0 ≤ p.2
theorem CommutingRepetition.JointSpectralData.setIntegral_fst_sq_tail {N : StdTracialAlgebra} {x y : N.H} {dA : SpectralData N x} {dB : SpectralData N y} (Jd : JointSpectralData dA dB) (H : ℝ) :
∫ (p : ℝ × ℝ) in {q : ℝ × ℝ | H < q.1}, p.1 ^ 2 ∂Jd.ν = ∫ (b : ℝ) in Set.Ioi H, b ^ 2 ∂dA.μ
theorem CommutingRepetition.JointSpectralData.setIntegral_snd_sq_tail {N : StdTracialAlgebra} {x y : N.H} {dA : SpectralData N x} {dB : SpectralData N y} (Jd : JointSpectralData dA dB) (H : ℝ) :
∫ (p : ℝ × ℝ) in {q : ℝ × ℝ | H < q.2}, p.2 ^ 2 ∂Jd.ν = ∫ (b : ℝ) in Set.Ioi H, b ^ 2 ∂dB.μ

Averaging and the parameter arithmetic #

theorem CommutingRepetition.sum_mul_sqrt_le_sqrt {ι : Type u_1} [Fintype ι] (π g : ι → ℝ) (hπ : ∀ (i : ι), 0 ≤ π i) (hπ1 : ∑ i : ι, π i = 1) (hg : ∀ (i : ι), 0 ≤ g i) :
∑ i : ι, π i * √(g i) ≤ √(∑ i : ι, π i * g i)

Jensen for the square root under a probability weight: ∑ πᵢ √gᵢ ≤ √(∑ πᵢ gᵢ) ("this is the sole square-root conversion in the proof").

theorem CommutingRepetition.norm_sub_sq_le_two_mul {E : Type u_1} [SeminormedAddCommGroup E] (x y u : E) :
‖x - y‖ ^ 2 ≤ 2 * ‖u - x‖ ^ 2 + 2 * ‖u - y‖ ^ 2

‖x − y‖² ≤ 2‖u − x‖² + 2‖u − y‖² (the step behind eq Dbar-Delta).

theorem CommutingRepetition.rpow_sixth_pow (Δ : ℝ) (hΔ : 0 ≤ Δ) :
(Δ ^ (1 / 6)) ^ 6 = Δ

(Δ^{1/6})^6 = Δ.

theorem CommutingRepetition.final_arith (C₀ δ ξ Γbar Ybar Dbar : ℝ) (hC₀ : 0 < C₀) (hδ : 0 ≤ δ) (hξ : 0 < ξ) (hα : δ + ξ ≤ 1 / 2) (hΓ : Γbar ≤ C₀ * (Dbar + √Dbar / (δ + ξ) + ξ ^ 2 / 32 + (ξ / 8) ^ 2)) (hD : Dbar ≤ 4 * δ ^ 6) (hY : Ybar ≤ δ ^ 6) :
4 * √Γbar + 4 * (δ + ξ) + 4 * √(ξ ^ 2 / 32 + (ξ / 8) ^ 2) + 2 * √Ybar + 4 * Γbar + 2 * ξ ^ 2 ≤ (4 * √(6 * C₀) + 24 * C₀ + 8) * (δ + ξ)

The final constant bookkeeping in the nontrivial range δ + ξ ≤ 1/2, with δ = Δ^{1/6}, ρ = ξ²/32, L = ξ/8, α = δ + ξ (06_otqcs.tex, eqs cutoff-choice, alpha-choice, alpha-optimization, Dbar-Delta): the averaged per-pair bound is at most a universal multiple of δ + ξ.

theorem CommutingRepetition.average_bound {ι : Type u_1} [Fintype ι] (π Γ Y ℓ : ι → ℝ) (C₀ δ ξ Dbar : ℝ) (hπ : ∀ (i : ι), 0 ≤ π i) (hπ1 : ∑ i : ι, π i = 1) (hΓ : ∀ (i : ι), 0 ≤ Γ i) (hY : ∀ (i : ι), 0 ≤ Y i) (hℓ : ∀ (i : ι), ℓ i ≤ 4 * √(Γ i) + 4 * (δ + ξ) + 4 * √(ξ ^ 2 / 32 + (ξ / 8) ^ 2) + 2 * √(Y i) + 4 * Γ i + 2 * ξ ^ 2) (hC₀ : 0 < C₀) (hδ : 0 ≤ δ) (hξ : 0 < ξ) (hα : δ + ξ ≤ 1 / 2) (hΓavg : ∑ i : ι, π i * Γ i ≤ C₀ * (Dbar + √Dbar / (δ + ξ) + ξ ^ 2 / 32 + (ξ / 8) ^ 2)) (hD : Dbar ≤ 4 * δ ^ 6) (hYavg : ∑ i : ι, π i * Y i ≤ δ ^ 6) :
∑ i : ι, π i * ℓ i ≤ (4 * √(6 * C₀) + 24 * C₀ + 8) * (δ + ξ)

Averaging the per-pair bound (06_otqcs.tex, the final display of the proof of thm otqcs): if every pair obeys the selected-state/bad-branch bound in terms of its grid disagreement Γᵢ and its alignment Yᵢ = ‖y − u‖², and the π-averages obey eqs common-shift and Dbar-Delta, then the π-average of the ℓ¹ errors is at most a universal multiple of δ + ξ, δ = Δ^{1/6}.

The trivial resource (degenerate range) #

noncomputable def CommutingRepetition.trivialResource (S T A B : Type) [Fintype A] [Fintype B] [Nonempty A] [Nonempty B] (N : StdTracialAlgebra) :

The trivial sampling resource of the degenerate range α₀ > 1/2 (06_otqcs.tex, proof of thm otqcs: "take explicitly N̂ = N, Ω = 1, Â_s^{a₀} = B̂_t^{b₀} = 1 and set all other output effects to zero").

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