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Logical DLA Parity Roadmap

This note is a post-NISQ planning artefact. It estimates resources for logical-level DLA parity work and keeps the survival claim blocked until the theory and simulation prerequisites are closed.

Boundary

roadmap and resource estimate only; no claim that DLA parity survives logical encoding and no hardware submission

Resource Table

N d Flat surface-code qubits Repetition scaffold qubits QEC rounds Wall-clock us/step p_L/round Step fidelity Status
16 3 272 80 3 3.000 9.000e-03 0.649209377 theory_required_before_simulation_or_hardware_promotion
16 5 784 144 5 5.000 2.700e-03 0.805735302 theory_required_before_simulation_or_hardware_promotion
16 7 1552 208 7 7.000 8.100e-04 0.913273392 theory_required_before_simulation_or_hardware_promotion

Multiscale QEC Cross-Check

  • Flat d=7 surface-code qubits: 1552
  • Flat d=7 logical error rate: 8.100e-04
  • MS-QEC qubits for distances [3, 3, 3, 3, 3]: 1360
  • MS-QEC effective logical rate: 1.000e+00
  • Overhead ratio MS-QEC/flat: 0.876289
  • Conclusion: hierarchical_lower_qubit_overhead_but_logical_rate_not_viable

Prerequisites

  • representation-theory review of XY Hamiltonian generators under the stabiliser group
  • logical observable definition for DLA parity before Monte Carlo promotion
  • noise-channel calibration separated from hardware-execution claims
  • negative-result framing if the logical code destroys the physical parity signal

Gate

Regenerate and compare this roadmap with:

scpn-bench s7-logical-dla-roadmap