IBM Quantum System Two, Donostia-San Sebastian

Raveh Neeman

doi:10.5281/zenodo.22674814

Basque Government (BasQ) - IBM-Euskadi Quantum Computational Center

IBM Quantum System Two, Donostia-San Sebastian

Basque Government (BasQ) - IBM-Euskadi Quantum Computational Center · superconducting circuits · DEPLOYED (Oct 2025) · 156 physical qubits · access: members of the IBM-Euskadi Quantum Computational Center; since Jul 2026 also open to industry and public-sector entities (requests to access@basquequantum.eus; access agreement with Ikerbasque, which manages the infrastructure)

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

Register profile — the machine's variant of its architecture

flags: no published error rates

Technologies by layer — the machine's cell per layer

1 Qubit carrier	Transmon · primary ▨ 🔎 156-qubit IBM Quantum Heron processor in a System Two; transmon not stated in the opened source
2 Encoding	Bare physical qubit (no encoding) · primary ◌ 🔎 bare transmon two-level subspace
3 Gate mechanism	Tunable-coupler CZ / iSWAP · primary ◌ 🔎 Heron generation: tunable-coupler gates (family-determined; not stated in the opened source)
4 Connectivity / transport	Static nearest-neighbour lattice · primary ◌ 🔎 static nearest-neighbour lattice (Heron; not stated in the opened source)
5 Control	Room-temperature electronics + per-qubit coax/flex · primary ◌ 🔎 room-temperature electronics (family-determined)
6 Readout	Dispersive microwave readout (+TWPA, Purcell) · primary ◌ 🔎 dispersive readout (family-determined)
7 Code	— none — nothing in this layer ◌ 🔎 no QEC code run on this machine located
8 Decoder	— none — nothing in this layer ◌ 🔎 no decoder; no QEC run
9 Interconnect	— none — nothing in this layer ▨ 🔎 one Heron processor; multi-processor integration only planned
10 Manufacturing	Superconducting-qubit lithography (Al/AlOx/Al junctions, Nb wiring, 300 mm) · primary ◌ 🔎 IBM superconducting-qubit fabrication (family-determined)

evidence: ✅ 0 / 10