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Symmetry- and Sector-Aware Mitigation Compiler

This page defines the bounded first contract for the mitigation compiler lane. The current implementation is a planner, not a circuit transformer. It decides whether existing primitives are eligible for a Kuramoto/XY experiment descriptor and returns explicit blockers when required evidence is missing.

Public API:

from scpn_quantum_control.mitigation import (
    SymmetrySectorProblem,
    plan_symmetry_sector_mitigation,
    replay_symmetry_sector_counts,
)

Inputs

SymmetrySectorProblem records:

  • n_qubits
  • symmetric finite coupling_matrix
  • finite omega
  • computational-basis initial_state
  • measurement basis: z, x, y, xyz, or counts
  • whether raw counts are available
  • whether noise-scaled symmetry observables are available for GUESS

Outputs

SymmetrySectorPlan records:

  • status: eligible or blocked
  • expected_parity
  • eligible primitives: parity_postselection, symmetry_expansion, guess_symmetry_decay
  • blockers
  • required evidence
  • benchmark gates
  • claim boundary

Failure modes

The planner blocks rather than guessing when:

  • the coupling matrix is not square, finite, and symmetric;
  • omega length or finiteness is invalid;
  • initial_state is not a computational-basis bitstring of length n_qubits;
  • raw counts are absent;
  • GUESS is requested without noise-scaled symmetry observables.

Benchmark gates

Before this planner is wired into execution paths, every integration must pass:

  • scpn-bench symmetry-sector-mitigation-gate
  • scpn-bench sync-benchmark-gate
  • hardware result-pack verifier for any raw-count replay claim
  • focused mitigation regression tests for the chosen primitive

Claim boundary

Planner output is an eligibility contract only. It does not mutate circuits, submit hardware jobs, prove improved hardware performance, or broaden DLA/GUESS claims without benchmark and raw-count evidence.

Raw-count replay adapter

replay_symmetry_sector_counts() is the first bounded execution adapter for the planner. It consumes an eligible SymmetrySectorProblem and offline raw computational-basis counts, then:

  • validates count keys, count values, bitstring length, and shot total;
  • applies parity postselection with explicit rejected-count accounting;
  • applies symmetry expansion while preserving the raw shot total;
  • reports GUESS as deferred until calibrated noise-scaled symmetry observable rows are wired into the replay contract.

The adapter does not mutate circuits, does not submit hardware jobs, and does not infer GUESS correction from raw counts alone.

The same scpn-bench symmetry-sector-mitigation-gate command now locks both planner fixtures and replay fixtures. Replay fixture rows cover the applied postselection/expansion path and the blocked missing-counts path.