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Circuit-cutting product boundary (BL-76)

scpn_quantum_control.circuit_cutting_product freezes and governs the existing circuit-cutting planner and partition-local simulator. It is a local, no-submit product surface; it does not claim general circuit reconstruction or large-N hardware execution.

Resource certificate

from scpn_quantum_control.bridge.knm_hamiltonian import build_knm_paper27
from scpn_quantum_control.circuit_cutting_product import (
    build_cutting_resource_certificate,
)

certificate = build_cutting_resource_certificate(
    build_knm_paper27(L=4),
    max_partition_size=4,
    shots_per_fragment=256,
)
assert certificate.feasible
assert certificate.fragment_evaluations == 1
assert certificate.estimated_total_shots == 256

The planner uses the ambient cut count and computes fragment_evaluations = 4**n_cuts and estimated_total_shots = fragment_evaluations * shots_per_fragment. The selected BL-47 policy supplies the per-fragment and total-shot ceilings. A non-finite 4**n_cuts estimate, an over-budget plan, an oversized partition, or a would-submit request is refused.

Synthetic reconstruction certificate

from scpn_quantum_control.circuit_cutting_product import (
    certify_synthetic_reconstruction,
)

evidence = certify_synthetic_reconstruction(
    observable_id="R_global",
    exact_value=0.8,
    reconstructed_value=0.79,
    declared_error_bound=0.02,
)
assert evidence.within_bound
assert evidence.synthetic_only
assert not evidence.hardware_result

The caller supplies the synthetic exact and reconstructed observables plus the bound. The certificate computes and checks the absolute error; it does not manufacture a reconstruction or convert simulation data into hardware evidence.

Fail-closed boundaries

  • The existing runner evolves partitions independently. With multiple partitions, its energy is partition_local_sum, and omitted cross-partition coupling is reported. It is not full-system energy.
  • Partition-local energy requires explicit caller acceptance.
  • Dense large-N all-to-all plans usually have prohibitive or non-finite 4**n_cuts overhead and are refused, not promoted as feasible.
  • BL-32 large-N family registration remains optional and is not implied by this product.
  • No product path submits a provider job or claims hardware advantage.