Nord Quantique Tesseract
Nord Quantique Tesseract
Register profile — the machine's variant of its architecture
qubit type: multimode GKP
gate mechanism: autonomous stabilisation; mid-circuit-measurement confidence score for real-time leakage suppression
connectivity: single cavity
control: room-temperature control
control placement: room-temp
readout: auxiliary-transmon readout
gate evidence: no published figure
codes: multimodegkp, tesseract_gkp
flags: post-selection dominates the result
Technologies by layer — the machine's cell per layer
| 1 Qubit carrier | Bosonic cavity mode · primary ▣ Fig. 1a (device schematic: double-post Al cavity, storage mode, auxiliary transmon chip) ✅ multimode GKP: two bosonic modes at different frequencies in one cavity form one logical qubit (announced 29 May 2025) |
| 2 Encoding | GKP grid encoding · primary ▣ Fig. 1b-d (characteristic-function tomography of grid states, Δ=0.38); §II.2 Grid-state encoding ✅ multimode GKP grid encoding; detects bit flips, phase flips, control errors and leakage |
| 3 Gate mechanism | Ancilla-mediated bosonic gates (cat CX, dual-rail CZ, beamsplitter) · primary ▣ Fig. 1e (sBs conditional displacements + auxiliary rotations); App. A.5 ECD gate ✅ autonomous stabilisation; mid-circuit-measurement confidence score for real-time leakage suppression; no logical 2Q data |
| 4 Connectivity / transport | Static nearest-neighbour lattice · primary ▣ Fig. 1a (single storage mode, one auxiliary transmon) ✅ single cavity, one logical qubit; no qubit–qubit connectivity (degree 0) |
| 5 Control | Room-temperature electronics + per-qubit coax/flex · primary ▤ App. A.1 Experimental device 🔎 room-temperature control; room-temp |
| 6 Readout | Dispersive microwave readout (+TWPA, Purcell) · primary ▣ Fig. 1a (on-chip readout resonator + Purcell filter); App. A.4 Mid-circuit measurements calibration ✅ auxiliary-transmon readout; mid-circuit measurement with confidence score |
| 7 Code | Bosonic concatenation (repetition-cat, LDPC-cat, GKP+qLDPC) · primary ▥ results ✅ tesseract (hypercubic two-mode) GKP code, 32 autonomous QEC rounds (sweep 7 Oct 2026, source read) |
| 8 Decoder | — (Atlas gap: ∅G-auton) · primary ▤ §II.2.2 Autonomous implementation via auxiliary reset; Fig. 2a (all-agree postselection) ✅ no classical decoder: autonomous stabilisation with heralded discard; no real-time decoder |
| 9 Interconnect | — none — nothing in this layer ▣ Fig. 1a (single cavity module) ✅ monolithic single cavity module, no interconnect |
| 10 Manufacturing | 3D machined superconducting cavities · primary ▤ §II.1 Experimental setup / App. A.1 Experimental device ✅ 3-D superconducting cavity hosting two modes; no fab process published Superconducting-qubit lithography (Al/AlOx/Al junctions, Nb wiring, 300 mm) · alternate ▤ §II.1 Experimental setup / App. A.1 Experimental device ✅ Josephson-junction lithography for the auxiliary transmon; no fab process published |
Standard records
acceptance fraction → 0.874 · per round (12.6% discard, Tesseract)
Oct 2025 · source
2Q layers per syndrome round → 32 cycles · best (consecutive QEC cycles with no measurable decay)
12.6% of runs discarded per round · May 2025 · source
evidence: ✅ 10 / 11