SQD result fields

The following 40 names match the sqd.result.v1 contract. JSON preserves these names and uses null for Python None. Every absent top-level value requires a null_reasons entry. Required metadata is not omitted. Nested objects retain their own units and reasons. A consumer must keep the method, tier, downgrade reason and warnings beside the reference energy.

Field	Unit	Meaning and absence rule
schema_version	metadata	Required, sqd.result.v1
status	metadata	Required, completed or reference_only
sqd_energy	Ha	SQD energy. Absent in reference-only mode
hf_energy	Ha	Required same-Hamiltonian determinant expectation
hf_reference_kind	metadata	Required canonical_rhf or fixed_frame_determinant
baseline_energy	Ha	Required selected reference energy
iso_active_space_ccsd_energy	Ha	Same-space CCSD. May be absent if not run in reference-only mode
iso_ndet_sci_energy	Ha	Matched-spin-dimension SCI. Absent in reference-only mode
iso_ndet_random_energy	Ha	Matched random comparison. Absent in reference-only mode or with an explicit unavailable/budget reason
baseline_tier	metadata	Required T0/T1/T1+/T2. Never infer from a legacy alias
baseline_method	metadata	Required actual method. CASCI stays exact_casci
baseline_uncertainty_mHa	mHa	T0 is zero. Unknown approximate uncertainty is absent with reason
baseline_uncertainty_kind	metadata	Required exact_active_space, solver_estimate or unknown
baseline_downgrade_reason	metadata	Absent for T0. Required nonempty text for every lower tier
baseline_untrustworthy	boolean	Required trust flag. Does not turn an approximation into T0
baseline_t1_residual	structured metadata	T1 cutoff/energy record. Absent when inapplicable. Energies are Ha, loose residual is mHa, and cannot bound the tight energy error
t1_diagnostic	dimensionless	T2 CCSD amplitude diagnostic. Absent when T2 is not used
t2_diagnostics	structured metadata	T2 flags, CCSD convergence, energies in Ha and dimensionless ratios. Absent when inapplicable
reference_attempts	structured metadata	Required ordered attempt records, including reasons, wall seconds and decimal MB peak where known
delta_mHa	mHa	SQD minus baseline. Absent in reference-only mode
delta_vs_sci_mHa	mHa	SQD minus same-size SCI. Absent in reference-only mode
ratio_sqd_over_sci	dimensionless	T0-relative error ratio. Absent for nonexact baseline, invalid denominator or reference-only mode, with reason
unique_dets_vs_shots	counts	Cumulative (shots, unique sampled pairs) curve. Absent in reference-only mode
active_space	counts	Required (electrons, spatial orbitals)
n_reps	count	Executed LUCJ repetitions. Absent in reference-only mode
shots	count	Executed sampling shots. Absent in reference-only mode
seed	integer	Required actual random seed, including reference-only runs
subspace_dim	count	Product of alpha/beta dimensions. Absent in reference-only mode
subspace_dims	counts	(d_alpha, d_beta). Absent in reference-only mode
full_ci_dim	count	Required full fixed-particle-number space dimension
embedding_mode	metadata	Required actual embedding mode
two_electron_tensor_fixed	boolean	Required fixed-tensor assumption
fixed_mo	boolean	Required orbital-frame assumption
backend	metadata	Executed sampling backend. Absent in reference-only mode
versions	mapping	Required exact dependency version snapshot
diagnostics	mapping	Required additional diagnostics. Retain embedded flags/reasons
provenance	mapping	Required immutable input/frame/Hamiltonian/seed source snapshot
timings_s	s	Required geometry/integrals/ccsd/prepare/sample/diagonalize/reference/comparison/total keys. Unexecuted stages are absent with reasons, not fabricated zero timings
null_reasons	mapping	Required reasons for missing values, including reference_only, not_applicable or the actual failure-to-define reason
warnings	metadata	Required warning collection. Every non-T0 baseline has a visible warning