IBM Quantum Falcon r5.11
IBM Quantum Falcon r5.11
Register profile — the machine's variant of its architecture
qubit type: fixed-frequency transmon
gate mechanism: fixed capacitive bus, CR/CX
connectivity: heavy-hex
control: room-temperature RF, coax per qubit
control placement: room-temp
readout: multiplexed dispersive
gate evidence: no published figure
decoder mode: offline — syndromes decoded after the run
codes: css_4_1_2, floquet_color, heavy_hex, honeycomb_floquet, matching, quantum_repetition, stab_4_2_2, stab_8_3_2
Technologies by layer — the machine's cell per layer
| 1 Qubit carrier | |
| 2 Encoding | Bare physical qubit (no encoding) · primary ▣ Fig. 5 (leakage to |2⟩); Methods: Leakage in the system ✅ Bare two-level subspace — Computational subspace of an anharmonic oscillator; leakage to |2⟩ is the price. |
| 3 Gate mechanism | Cross-resonance (fixed-frequency, all-microwave) · primary ▤ Methods: Leakage in the system (cross-resonance frequency collisions) 🔎 fixed capacitive bus, cross-resonance CR/CX |
| 4 Connectivity / transport | Static nearest-neighbour lattice · primary ▣ Fig. 1 (distance-3 heavy-hexagon code on 23 qubits); Fig. 4a (Falcon numbering) ✅ heavy-hex, degree 3 max / 2.3 mean (2022) |
| 5 Control | |
| 6 Readout | Dispersive microwave readout (+TWPA, Purcell) · primary ▣ Fig. 5a (repeated measurement sequence); Methods: Leakage in the system ✅ multiplexed dispersive |
| 7 Code | Error-detection codes ([[4,2,2]], d=2 surface, iceberg, spacetime) · primary ▤ Nature 625, 259 (2024), main text and Methods ✅ [[4,2,2]] error-detecting code: magic state encoded with detection and post-selection on ibm_peekskill (27-q Falcon); logical infidelity (1.23±0.11)×10⁻² post-selected vs best physical two-qubit magic state (2.354±0.271)×10⁻² — beyond break-even Rotated surface code (+ yoked variants) · alternate ▣ Fig. 1 (heavy-hexagon code gauge operators) ✅ nearest technology to heavy_hex subsystem code (d=2 2017, d=3 2022–23); also stab_4_2_2 flag-FT state prep, honeycomb_floquet plaquette measurement |
| 8 Decoder | MWPM / Sparse Blossom (+ correlated matching) · primary ▣ Fig. 6 (four decoding methods); Methods: MWPM edge probabilities; Maximum likelihood ✅ matching and maximum-likelihood decoding of the heavy-hex code, offline — none — nothing in this layer ▤ §Results: Decoding algorithms ✅ offline decoding only; no real-time decoder in the loop |
| 9 Interconnect | |
| 10 Manufacturing | Superconducting-qubit lithography (Al/AlOx/Al junctions, Nb wiring, 300 mm) · primary ◌ 🔎 IBM 200 mm superconducting-qubit lithography; standard package |
Standard records
connectivity degree → 3 neighbours · max (2.3 heavy-hex mean)
heavy-hex lattice · 2022 · source
evidence: ✅ 8 / 12
Pictures
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