System Model H2 (H2-1, H2-2)
System Model H2 (H2-1, H2-2)
Register profile — the machine's variant of its architecture
qubit type: hyperfine clock qubit
gate mechanism: laser Molmer-Sorensen; arbitrary-angle RZZ + SU(4)
connectivity: all-to-all by transport around the racetrack
control: room-temperature electronics + free-space laser beams (gate beam pairs, 'sheet' cooling beams); ~4.8 control signals per qubit
control placement: room-temp + optics
readout: fluorescence with mid-circuit measurement and reset
gate evidence: a number stated by the vendor, protocol unstated
decoder mode: feed-forward — the decoder's result acts inside the run (closed loop)
codes: 4d_surface, carbon, generalized_shor, iceberg, lr_enhanced_surface, quantum_double, qubit_golay, stab_15_1_3, stab_16_6_4, steane, surface
flags: code id missing in the register
Technologies by layer — the machine's cell per layer
| 1 Qubit carrier | Trapped atomic ion · primary ▣ Fig. 1 (racetrack surface-electrode trap, Yb-Ba crystals); §II ✅ 56 ¹⁷¹Yb⁺ hyperfine clock qubits on two connected linear sections of one racetrack (32 q Jun 2023 → 56 q Jun 2024) |
| 2 Encoding | Hyperfine / clock-state qubit · primary ▤ §II (The H2 quantum computer) ✅ ¹⁷¹Yb⁺ ground-state hyperfine clock qubit |
| 3 Gate mechanism | Mølmer–Sørensen / light-shift laser gate · primary ▣ §II (native U_ZZ(θ), crystal merge); App. A1.C + Fig. A2 (2Q RB, 4 gate zones) ✅ laser Mølmer–Sørensen; arbitrary-angle RZZ + SU(4); 2Q infidelity <1×10⁻³ |
| 4 Connectivity / transport | Ion shuttling (QCCD, junctions, grid traps) · primary ▣ Fig. 1 (racetrack trap); §II (transport, split/combine, swap) ✅ QCCD racetrack, all-to-all by transport; degree 55 (56 qubits) |
| 5 Control | Free-space laser addressing of ions (AOM/AOD beams) · primary ▨ 🔎 room-temperature electronics; free-space gate beam pairs and sheet cooling beams (no integrated photonics) |
| 6 Readout | Fluorescence state detection (ions, defects) · primary ▤ App. A (The H2 quantum processor) 🔎 fluorescence with mid-circuit measurement and reset (MCMR) |
| 7 Code | High-rate concatenated codes with transversal gates · primary ▤ ✅ [[16,4,2,4]] tesseract and [[12,2,4]] carbon codes with Microsoft; 11×–800× logical-over-physical improvement (Jun 2026) Colour code (transversal Cliffords) · alternate ▣ Fig. 3 (transversal teleport), Fig. 4 (lattice surgery), Fig. 7 (Steane code) ✅ Steane [[7,1,3]] logical teleportation: transversal 0.975(2) vs lattice surgery 0.851(9), with real-time decoding Magic-state factory (cultivation / distillation / code switching) · alternate ▤ ✅ [[15,1,3]] quantum Reed–Muller → [[7,1,3]] code switching; magic-state infidelity ≤5.1(2.7)×10⁻⁴ at 82.58% acceptance |
| 8 Decoder | |
| 9 Interconnect | — none — nothing in this layer ▣ Fig. 1 (single racetrack trap) ✅ monolithic single module, no interconnect |
| 10 Manufacturing | Ion-trap fabrication (surface-electrode chips; machined 3D blade traps) · primary ▤ §II (surface-electrode trap); Acknowledgments (trap fabricated by Honeywell) 🔎 surface-electrode racetrack trap chip; no H2-specific fab source in the note Optical / mechanical assembly (lasers, vacuum, objectives) · alternate ◌ 🔎 room-temperature optics and vacuum assembly around the surface trap; no H2-specific source |
Standard records
control lines per qubit → 4.8 lines/qubit · typical
2025 · source
evidence: ✅ 9 / 13
Pictures
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