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Structure before circuit tricks

Preconditioned function preparation with an explicit envelope

Uniform-state postselection can have exponentially small filling fraction in dimension; a reference should match localization without hiding an equally hard preparation problem.

research target setting:coherent-envelope-ratio

\[\kappa_{\rm env}=\frac{C\|g\|_2}{\|f\|_2},\quad p_{\rm succ}=\kappa_{\rm env}^{-2},\quad C\ge\max_{g_j\ne0}|f_j/g_j|\]

Frozen target and input model

Construct g for one useful localized function class so that reference preparation, ratio implementation and amplification are all controlled.

Access model: A clean U_g and U_g-dagger with charged construction; coherent access to a bounded complex ratio; classical or certified scalar C.

  • support(f) subset support(g); define the ratio as zero off support(g)
  • f and g nonzero and C>0
  • A constructive domination certificate, not an empirical maximum on a few grid points

Desired result, not an achieved bound

For a selected class, prove kappa_env and reference/ratio costs polynomial in declared class parameters; add a model-matched obstruction or lower bound.

Coherent rejection and reweighting are prior art. Uniform g recovers kappa_env=1/F2 where F2=||f||2/(sqrt(M)||f||infinity). A small ratio on average does not imply a valid pointwise envelope.

Dependency-ready execution route

01

Formalize support-aware coherent reweighting and its exact success probability.

Acceptance: All amplitudes including zero-reference entries and complex phases agree; normalizer nonzero.

planned; no claimed closure

02

Build a certified reference for a restricted localized class.

Acceptance: A concrete supplier for g, a global domination proof and kappa bound.

planned; no claimed closure

03

Add robust ratio approximation and amplification.

Acceptance: State error and actual query/primitive costs, including U_g inversion and repeated calls.

planned; no claimed closure

Next bounded advance: First close the support-aware probability identity, then study anisotropic product envelopes and a controlled perturbation class.

Reusable mathematics

No local transport theorem is bound to this record. Do not infer formal truth from its position in the atlas.

Lower-bound comparison contract

source-audit-pending

Audit the quantum rejection-sampling query lower bound and prove whether its oracle assumptions match this structured envelope model before transferring it.

Same-model key: setting:coherent-envelope-ratio

Diagnostic examples, not proofs

  • Localized Gaussian profiles
  • Boundary-layer initial data
  • Piecewise payoff functions with declared phase convention

Primary-source ledger

Quantum Rejection Sampling

primary-metadata-checked Authors' publication page: quantum state generation, query characterization and matching lower bound

Prior art for coherent amplitude reweighting. Novelty must be in an explicit structured envelope, guarantees, implementation or model-matched bound, not in rejection sampling itself.

Quantum State Preparation without Coherent Arithmetic

primary-metadata-checked Abstract; Physical Review Letters 136, 240603, published 18 June 2026

QET-based function preparation with few ancillas. Approximation, normalization and success probability remain separate costs.

Download bounded agent / contributor packet

python3 website/scripts/research_atlas.py context --route spw-envelope