Logbook — 2026-04-13 — Architect-stance note: WP-E renaming before v0.4

[Stance: Architect] — the design question Guardian raised twice and the v0.3 framing cannot carry unchanged into v0.4.

The question

Should WP-E, currently titled "Forward Map and Observability: Phase and Contrast Maps of the Stroboscopic Analysis Pulse", be renamed before v0.4 lands?

Guardian noted in the R2 review:

"The original 'Forward Map and Observability' framing presumed a three-axis forward map with nontrivial structure in each axis. The actual finding is that the map factorises (|C| is one-dimensional in δ₀; arg C carries all the (|α|, φ_α) information on the unit circle via a closed-form identity) and that the R2 'alternative forward map' is a theoretical sideline."

And in the S2 falsification review:

"There is a version of v0.4 in which WP-E is no longer 'Forward Map and Observability' but rather 'The Position-Phase Channel of Stroboscopic Analysis' — a tighter, more specific object."

The question has been deferred twice. It must be resolved before v0.4 drafting, not after.

Architect reading

Four things have happened since v0.3:

1. Preflight. Closed motivation 3 at the data-artefact level (HDF5 synthetic, JSON legacy = engine). No physics residual.
2. S1 + R1. Confirmed |C|(δ_0) is α-independent at the carrier and showed position-phase (arg C) tracks k_eff · ⟨x⟩ linearly in R1.
3. S2 falsification + expansion. Matrix-element-magnitude theorem: |C|(δ_0, |α|, φ_α) is φ_α-independent to machine precision. arg C(δ_0 = 0, |α|, φ_α) = 90° + 2η|α|·cos φ_α exactly (10⁻¹¹ deg residual) in both engines.
4. H1 + R2. Lock tolerance is |α|-dependent (FWHM 3.3 % in ε at |α| = 3). R2 reveals a frame-convention choice; Δt decomposition is not well-posed in the original v0.3 sense.

The three nouns in the v0.3 title — "Forward Map", "Observability", "Phase and Contrast Maps" — have fared differently:

• "Forward Map": the map exists, but it factorises. It is one-dimensional in the contrast direction and one-dimensional (with a trivial 2D embedding onto the unit circle) in the phase direction. Calling it a "map" overclaims its structure.
• "Observability": operationalised cleanly by H1 (lock tolerance) and the S2 confirmation that arg C is the measurable signal. Still meaningful.
• "Phase and Contrast Maps": accurate but generic. The contrast "map" is trivial (flat in α, φ_α); the phase "map" is a closed-form cosine. A single figure suffices for each — calling them "maps" sets up an expectation of rich 2D structure that the data do not match.

The three motivations originally listed have collapsed:

What remains, concretely, is one closed-form result about the spin response — arg C(δ_0 = 0) = 90° + 2η|α| · cos φ_α — and two supporting-cast observations (Magnus bias at η · 518 kHz, lock FWHM 3.3 % at |α| = 3). That is a narrower object than "forward map".

Renaming options

Three candidates, in descending order of scope reduction:

Option A — "The Position-Phase Channel of Stroboscopic Analysis"

Guardian's proposed name. Describes exactly what the WP delivered: a closed-form identity for the measurement phase in terms of motional amplitude and phase. Drops "forward map" entirely.

• Pros: Reflects the actual result. Reader arrives with the right expectation. The injectivity question (v0.3 §4 deliverable 5) becomes natural: "is arg C(|α|, φ_α) injective on the unit circle?"
• Cons: Reads as if Doppler-channel work was out of scope from the start, whereas in fact it was attempted and failed. Loses the historical narrative that the scope reduction was earned.
• Mitigation: the v0.4 text narrates the 3 → 1 reduction explicitly in the introduction, crediting the preflight and S2 falsification. The title reflects the final object; the body reflects the history.

Option B — "Forward Map of Phase and Contrast; Position-Phase Channel"

Compound title retaining both framings. Acknowledges that the WP began as a forward-map exercise and ended as a position-phase characterisation.

• Pros: Honest about the history. A reader skimming the title gets both the original and final framings.
• Cons: Clunky. Two-part titles rarely survive casual reference; the WP will be referred to as whichever half dominates. In practice it will become "the phase-contrast WP" or "the position-phase WP" within a week.

Option C — Keep v0.3 title, subtitle the scope reduction

Keep "Forward Map and Observability". Add a subtitle like "(position-phase channel closed; velocity channel demonstrated inapplicable for coherent states)".

• Pros: Zero cross-reference churn. The architecture doc, dossier, and preflight entries already name "WP-E — Forward Map and Observability"; renaming would require syncing all of them.
• Cons: The body of the v0.4 README will clearly say "this is about the position-phase channel", producing a title/body mismatch the reader has to translate each time.

Recommendation

Option A, committed now, before v0.4 drafting.

Reasoning:

1. The renaming cost is finite and bounded. Cross-references are in ../README.md (the WP itself), its logbook entries (historical, need not be changed — they logged what was true at their writing), and the commit history. The dossier and ARCHITECTURE.md have not yet been updated to reference WP-E; the v0.3 preflight-results entry noted this update as an outstanding action and it was never done. So the renaming is internal to WP-E's own folder.

2. The title-body mismatch cost is unbounded. Every future reader, reviewer, and derivative work sees a mismatch that needs explaining. The cumulative tax exceeds the one-time renaming cost within two or three reads.

3. Council meta-lesson ("one worked example beats three revision cycles") applies. Commit to the framing now so v0.4 is written against it, rather than drafted under one framing and re-drafted under another.

4. The historical narrative survives. The title reflects the terminal object; the introduction narrates the 3 → 1 reduction. This is how every published paper works — the abstract describes what was found, not the path to finding it. Nobody expects the title of a paper to encode its authors' previous hypotheses.

Commitments for v0.4 under Option A

If Option A is adopted:

• New title: WP-E — The Position-Phase Channel of Stroboscopic Analysis
• Numbering unchanged: still "WP-E" in the Breakwater architecture.
• Subtitle remains: "Work Program — v0.4 — 2026-XX-XX".
• Introduction narrates the history: 3 motivations in v0.3 → 1 motivation delivered in v0.4. The preflight and S2 findings are named as the scope-altering discoveries.
• §3 Purpose: "map the closed-form identity arg C(δ_0 = 0, |α|, φ_α) = 90° + 2η|α|·cos φ_α and its deviations at η ≠ 0; characterise the stroboscopic-lock tolerance |C|(ε); localise the Magnus carrier bias."
• §4 Deliverables: renumbered/trimmed. The 6-item v0.3 list reduces to: 1. Dataset (S1, S2 at α ∈ {1,3,5}, R1, R2 reference, H1, fine-grid confirmations). 2. Figures: S2_combined.png as headline; S1_carrier_summary.png, H1_lock_tolerance.png, R2_vs_full.png, S1_carrier_zoom.png, R2_fine_tooth.png as supporting. 3. Short note (≤ 2 pp) summarising the position-phase identity and three measured deviations. 4. Logbook (done).
• §8 Q-list: most questions now closed; remaining open items are the experimental-team correspondence (Flag 1) and the WP-C pointer to thermal states.

Veto assessment (Architect-internal)

Option A is the clean choice. No structural objection. Adopted with the commitments above pending user confirmation.

Action

Gate on user confirmation. Before drafting v0.4, the WP author (user) is asked to confirm Option A (rename to "The Position-Phase Channel of Stroboscopic Analysis") or prefer a different option.

If Option A is confirmed:

• v0.4 drafting proceeds under the new title.
• This entry is cited from v0.4 §1 as the record of the renaming decision.
• No README edit until v0.4 lands.

If Option B or C is preferred: revise this entry, no further action needed.

Guardian cadence still: no README edit until v0.4.