OQC Toshiko

Raveh Neeman

doi:10.5281/zenodo.22674814

Oxford Quantum Circuits · superconducting circuits · DEPLOYED (2024) · 32 physical qubits · access: cloud service in colocation data centres (UK, Spain, Japan)

architecture: Transmon lattice with tunable couplers · Open on the map

Register profile — the machine's variant of its architecture

qubit type: Coaxmon - patented 3-D out-of-plane coaxial control architecture, no on-chip control wiring

gate mechanism: not published - no native 2Q gate name, gate time or degree anywhere in OQC's material

connectivity: not published

control: control and readout enter perpendicular to the chip plane

control placement: room-temp (out-of-plane)

readout: dispersive

gate evidence: no published figure

flags: no published error rates, specification absent

Technologies by layer — the machine's cell per layer

1 Qubit carrier	Transmon · primary ▣ Fig. 1D-F (four-qubit coaxmon circuit in enclosure; transmon + spiral resonator); §II Device architecture ✅ Coaxmon transmon: 3-D out-of-plane coaxial control, no on-chip control wiring; 32 qubits, third generation (after Lucy 8, Sophia 4)
2 Encoding	Bare physical qubit (no encoding) · primary ◌ 🔎 bare transmon two-level subspace; no encoding beyond the physical qubit
3 Gate mechanism	— undisclosed — exists, nothing published ▣ Fig. 5 (single-qubit RB only); §V Single qubit gate errors ✅ gate mechanism not published: no native 2Q gate name, gate time or connectivity degree; no 1Q/2Q fidelities published
4 Connectivity / transport	Static nearest-neighbour lattice · primary ▣ Fig. 1D (four qubits in a square lattice, 2 mm spacing); §II ✅ nearest-neighbour lattice assumed; connectivity not published
5 Control	Vertical (out-of-plane) signal delivery — VIO, coaxmon, 3D wiring · primary ▣ Fig. 2A (cross-section of out-of-plane wiring addressing a qubit); Fig. 1A-B (through-holes for out-of-plane wiring) ✅ Coaxmon out-of-plane I/O: control and readout enter perpendicular to the chip plane; no Atlas technology Room-temperature electronics + per-qubit coax/flex · alternate ▣ Fig. 4A (qubit control line selectivity); §IV.A 🔎 room-temperature control delivered out-of-plane (Coaxmon)
6 Readout	Dispersive microwave readout (+TWPA, Purcell) · primary ▤ §III Basic characterization / §IX Materials and Methods (heterodyne single-shot readout, 5 µs pulses) 🔎 dispersive readout, entering out-of-plane; no readout fidelity published
7 Code	— none — nothing in this layer ▦ 🔎 no QEC; operates entirely with physical qubits (L0)
8 Decoder	— none — nothing in this layer ▦ 🔎 no decoder; no QEC run
9 Interconnect	— none — nothing in this layer ◌ 🔎 monolithic single module, no interconnect; separate single-system sites (UK, CESGA Spain, Equinix TY11 Tokyo)
10 Manufacturing	Superconducting-qubit lithography (Al/AlOx/Al junctions, Nb wiring, 300 mm) · primary ▤ §IX Materials and Methods (enclosure CNC-machined 6061 Al; SPC UT47 coax out-of-plane wiring) ✅ superconducting-qubit lithography (OQC); no machine-specific fab source

evidence: ✅ 5 / 11