System Model H1 (H1-1)
System Model H1 (H1-1)
Register profile — the machine's variant of its architecture
qubit type: hyperfine clock qubit
gate mechanism: laser Molmer-Sorensen; native RZZ(theta) arbitrary-angle ZZ, general SU(4)
connectivity: linear QCCD racetrack, all-to-all by transport
control: room-temperature electronics + free-space laser beams focused into gate zones, propagating parallel to the trap surface; ~10 control signals per qubit
control placement: room-temp + optics
readout: fluorescence, destructive per ion; 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: css_4_1_2, dfs_qec_10_1_4, iceberg, stab_16_6_4, stab_4_2_2, stab_5_1_3, stab_6_2_2, stab_8_3_2, steane, toric
flags: emulator numbers, source not confirmed, status unresolved
Technologies by layer — the machine's cell per layer
| 1 Qubit carrier | Trapped atomic ion · primary ▣ Fig. 2 (trap loaded with 10 Yb-171 + 10 Ba-138 ions) ✅ 20 ¹⁷¹Yb⁺ qubit ions, hyperfine clock qubit; ¹³⁸Ba⁺ co-trapped for sympathetic cooling (20-qubit upgrade, v5.20 data sheet Feb 2023) |
| 2 Encoding | |
| 3 Gate mechanism | Mølmer–Sørensen / light-shift laser gate · primary ▤ §Background (hardware: stimulated-Raman 1Q/2Q gates) ✅ laser Mølmer–Sørensen; native arbitrary-angle RZZ(θ), general SU(4); Azure emulator parameters p1 = 4×10⁻⁵, p2 = 3×10⁻³ |
| 4 Connectivity / transport | Ion shuttling (QCCD, junctions, grid traps) · primary ▣ Fig. 2 (QCCD surface trap); §Background (transport primitives) 🔎 linear QCCD racetrack, all-to-all by transport; degree n−1 = 19 within the chain after transport |
| 5 Control | Free-space laser addressing of ions (AOM/AOD beams) · primary ▨ 🔎 room-temperature electronics; free-space laser beams focused into the gate zones, propagating parallel to the trap surface (no integrated photonics) |
| 6 Readout | Fluorescence state detection (ions, defects) · primary ▤ §Background (state-dependent fluorescence) ✅ fluorescence, destructive per ion; mid-circuit measurement and reset; Azure emulator p_meas = 3×10⁻³, measurement crosstalk 1×10⁻⁵ |
| 7 Code | High-rate concatenated codes with transversal gates · primary ▤ 🔎 [[6,2,2]] code (2 logical in 6 physical) run on H1-1; register codes steane;stab_6_2_2 Colour code (transversal Cliffords) · alternate ▣ Fig. 1 ([[7,1,3]] color code); Fig. 3 (logical fidelities) ✅ Steane [[7,1,3]]: logical QAOA and HHL on encoded data with JPMorganChase (Mar 2026, across H1/H2/Helios) Error-detection codes ([[4,2,2]], d=2 surface, iceberg, spacetime) · alternate ▤ main text (experiments on Quantinuum H1-2) ✅ iceberg [[k+2,k,2]] code: 8 logical qubits in all 12 qubits of H1-2, mid-circuit syndrome measurement, shots with a detected error discarded (Sep–Oct 2022) Magic-state factory (cultivation / distillation / code switching) · alternate ▤ 🔎 [[6,2,2]] logical non-Clifford controlled-H past break-even: 2.3×10⁻⁴ vs 1.0×10⁻³ physical (2.9×), Jun 2025, H1-1 |
| 8 Decoder | — (Atlas gap: ∅G-lut) · primary ▣ Fig. 8 (decoder procedure); §Experiments: Decoder ✅ real-time lookup-table decoding of Steane [[7,1,3]] in-loop since 2021; no LUT node among the Atlas's dec_* nodes |
| 9 Interconnect | |
| 10 Manufacturing | Ion-trap fabrication (surface-electrode chips; machined 3D blade traps) · primary ◌ 🔎 in-house surface-electrode trap microfabrication; cryogenic surface trap (~10 K) Optical / mechanical assembly (lasers, vacuum, objectives) · alternate ◌ 🔎 room-temperature optics around the cryogenic surface trap; free-space/integrated laser delivery |
Standard records
control lines per qubit → 10 lines/qubit · typical
the highest of the H-series · 2025 · source
SPAM error → 3.00e-3 · typical (Azure emulator parameter, not a device median)
Feb 2026 · source
evidence: ✅ 6 / 14