IQM Star 24

Raveh Neeman

doi:10.5281/zenodo.22674814

IQM Quantum Computers · superconducting circuits · DEPLOYED (Sep 2025 (first 24-qubit Star delivered as VLQ at IT4I; on IQM Resonance as IQM Star 24 by Sep 2026)) · 24 physical qubits · access: cloud (IQM Resonance)

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

Register profile — the machine's variant of its architecture

qubit type: tunable transmon

gate mechanism: tunable couplers to a central computational resonator

connectivity: central bus resonator giving all-to-all within the cell

control: room-temperature RF

control placement: room-temp

readout: dispersive

gate evidence: no published figure

Technologies by layer — the machine's cell per layer

1 Qubit carrier	Transmon · primary ▣ Fig. 1a (QPU schematic: 4 data + 2 ancilla qubits around central resonator); App. G (qubit specifications) ✅ tunable transmon; 24-qubit Star on IQM Resonance cloud
2 Encoding	Bare physical qubit (no encoding) · primary ◌ 🔎 bare transmon two-level subspace; no encoding beyond the physical qubit
3 Gate mechanism	Tunable-coupler CZ / iSWAP · primary ▣ Fig. 1a (tunable couplers, green, to central resonator); Fig. 1b (resonator-qubit CZ and MOVE gates) ✅ tunable couplers to a central computational resonator
4 Connectivity / transport	— (Atlas gap: ∅G-bus) · primary ▣ Fig. 1a (star topology: all qubits coupled only to the central resonator Res.) ✅ Star topology: central computational resonator bus giving all-to-all within the cell (degree 23); neither cx_nn nor cx_lr
5 Control	Room-temperature electronics + per-qubit coax/flex · primary ▥ 🔎 room-temperature RF control
6 Readout	Dispersive microwave readout (+TWPA, Purcell) · primary ▤ App. G (Qubit specifications); Fig. 1b (ancilla measurements, final data-qubit readout) 🔎 multiplexed dispersive readout (IQM)
7 Code	— none — nothing in this layer ▣ §V (Repeated error detection); Fig. 2 (stabilizer expectation values); App. A ([[4,2,2]] codewords) ✅ no QEC code run on IQM hardware; NISQ device (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
10 Manufacturing	Superconducting-qubit lithography (Al/AlOx/Al junctions, Nb wiring, 300 mm) · primary ◌ 🔎 superconducting-qubit lithography (IQM); no machine-specific fab source

evidence: ✅ 4 / 10