STAR-PHASER SOLAR

SOLAR encodes one decit as |ψ⟩ ∈ ℂ² ⊗ ℂ⁵ — a parity subspace (2 levels) times a symbol subspace (5 levels). Decimal digit d = 5p + s where p ∈ {0,1} selects sub-band and s ∈ {0,…,4} the tooth within it.

Sub-band p=0 (digits 0–4):  f_{0,s} = f_ref + s·Δf
Sub-band p=1 (digits 5–9):  f_{1,s} = f_ref + Δf_guard + s·Δf
Δf = 50 GHz · Δf_guard ≥ 100 GHz

An engineer with an OSA sees two clusters of five lines — left cluster reads 0–4, right reads 5–9. This is intentional symbolic transparency, unlike GF(64) NOVA where 64 teeth are an algebraic grid.

Critical honesty: ℂ¹⁰ ≅ ℂ² ⊗ ℂ⁵ as vector spaces, but ℤ₁₀ addition does not factorize — DADD must respect carry across the (p,s) boundary (e.g. 4+7 flips parity).

How we do it: Mask two 5-ring shaper banks on the shared SiN bus; firmware LUT maps DQFP |d⟩ ↔ physical (p,s) amplitudes; publish spectral legend card on bring-up.

SOLAR executes Spectral Decimal Computing (SDC) through the Decimal Quantum Frequency Processor ISA compiled to EOM+shaper QFP cascades:

• FAU — DADD, DSUB, DMUL, DDIV (mod-10 ring arithmetic)
• SPU — PHASE (Z₁₀), DFT10, IDFT10 on dual 5-ring shaper banks
• QFR — FSHIFT, FCYCLE, SWAP10, ENTANGLE10
• SDCLA — O(log₁₀ N) decimal carry via spectral Gᵢ/Pᵢ cells
• FMC — LOAD, STORE, COPY via SFWM comb memory

Primitives: X₁₀ (shift), Z₁₀ (phase), F₁₀ (decimal QFT). Identity F₁₀ X₁₀ F₁₀† = Z₁₀ is the algebraic backbone of Fourier-basis DMUL.

ℤ₁₀ limits: no GF(10) inverse (2⁻¹ mod 10 undefined); no char-2 XOR-add; no native RS/BCH — defer to GALAXY GF(16).

How we do it: Port G05–G11 ISA to 2×5 compiler backend; tensor ops emit band-local vs cross-band tags; OPC node after every 3–5 cascade stages bounds phase error.

A SOLAR decit begins as ten phase-coherent spectral lines from one pump via SFWM on a high-Q Si₃N₄ microring — same physics as Kues D=10 [demonstrated external].

Fab stack (B07): inserts into Steps 01–06 of manufacturing.html — SiN passives (comb ring, AWG, shaper rings), TFLN bond for EOMs, As₂S₃ OPC overlay post-bond (<210 °C golden rule). SOLAR is a subset mask of GALAXY/NOVA comb tiles, not a one-off chemistry experiment.

2×5 spectral shaping: pump detuning targets two five-line clusters rather than ten uniform adjacent lines — reduces adjacent-channel crosstalk during lock.

How we do it: Tape out comb ring + dual 5-ring shapers + AWG + microring bank; bond TFLN EOM via wafer-scale direct bond; deposit As₂S₃ OPC only at encoding-boundary sections; run T-B07 experiments 1–5 at d=10.

After DQFP compute, SOLAR resolves which decimal digit was stored via spectral routing:

• Parallel — 10-ch AWG or 10-ring demux → 10 SPADs (single-shot read)
• Staged 2×5 — parity discriminator + 5-ch demux per band (7 effective channels)
• Project-then-detect — QFP unitary → 1 demux → tomography / gate cert

B09 honesty: 10-ch demux crosstalk and SPAD calibration are the true gating risks for base-10 — explicitly not OPC bandwidth. Target F_read ≥ 0.98 on interior bins at ε ≤ 1% crosstalk.

How we do it: Place AWG + microring demux on mask (dual-variant strategy); calibrate confusion matrix C classically; implement 5+2 staged firmware aligned to S12 legend; wire 10 SPAD channels at package.

Wafer resonance scatter (5–15% of FSR) misplaces teeth off the 50 GHz grid. Comb lock makes frequency labels trustworthy — without it, the human-readable spectral map is fiction.

L0 Global TEC        → ±5 GHz coarse
L1 Band coarse (2×5) → align Δf_guard between parity clusters
L2 Per-tooth (10)     → |Δf_err| < 0.5 GHz via TED heaters

grid_valid BOOL gates DQFP issue logic — compute stalls if FALSE. SOLAR is the low-channel-count shakedown for NOVA's 64-tooth lock (G47 scaled down).

How we do it: Integrate 13 heater channels with thermal-isolation trenches; port G47 firmware to 10-tooth / 2-band instance; implement independent TED matrices per 5-ring bank; lock target < 30 s per die at room temp.

Region I SOLAR uses OPC as boundary correction, not distributed field computing. One broadband As₂S₃ FWM pass conjugates φ→−φ on all ten colors simultaneously — 12 THz ≫ 450 GHz (≈27× margin).

Boundary map: GEMINI→SOLAR transcode output; sub-band A↔B midpoint; post-QFP every 3–5 stages; pre-demux readout. Optional decit squeeze bridge (G25) narrows inter-bin Δφ between major QFP stages — CV-assisted DV, not GKP logical encoding.

Never-state: OPC corrects phase only (~3 dB/pass loss remains); it does not replace qudit QEC.

How we do it: Localized As₂S₃ patches post-TFLN bond; pump at band center of 450 GHz span; demonstrate single-photon OPC on dual-rail first (A104 §5), inherit to 10-bin; feed Z-bias metrics to qudit decoder co-model.

Investors routinely conflate "d=10 qudit" with "GF(10) field element." SOLAR explicitly breaks that conflation.

• Native decimal digits 0–9 — yes
• Addition / multiplication mod 10 — yes (ℤ₁₀ ring)
• Every nonzero element has inverse — no (zero divisors {2,5})
• Reed–Solomon over GF(10) — no (GF(10) does not exist)

QEC menu: Option A — ℤ₁₀ qudit codes (immature literature); Option B — prime-power engine + decimal I/O; Option C — OPC + embedded qubit surface code; Option D (recommended) — defer mature QEC to GALAXY; SOLAR = pre-QEC validation chip.

How we do it: Chip page banner states ℤ₁₀ not GF(10); software ABI exposes DMUL/DADD as mod-10 with zero-divisor documentation; no GFINV opcode; customer migration doc to GALAXY when field QEC needed.

SOLAR is intermediate decimal-native photonic control — the human-legible control plane between GEMINI qubits and field-native GALAXY/NOVA.

• T0 Bring-up — comb lock cert, confusion matrix, gate tomography
• T1 Control — decimal phase schedules, calibration tables
• T2 Arithmetic lab — SDCLA demo, native DADD/DMUL benchmarks
• T3 Symbolic hybrid — spectral register as visible state machine
• T4 AI / crypto — defer to NOVA (MATMUL10, RS coding)

Hybrid workflow: engineer reads digit 7 on OSA → firmware writes |7⟩ = |1⟩⊗|2⟩ → SDCLA DADD → OPC refresh → demux confirms ch7.

How we do it: Ship SOLAR SDK with decit_write(d), decit_read(), dadd(a,b); bundle calibration suite (C-matrix + PHASE sweep + SDCLA golden tests); publish migration guide to GALAXY for field inverse/DIV needs.