IQM Garnet (IQM Crystal 20)

Raveh Neeman

doi:10.5281/zenodo.22674814

IQM Quantum Computers · superconducting circuits · DEPLOYED (2024) · 20 physical qubits · access: cloud (Amazon Braket, 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, native CZ

connectivity: Crystal square lattice, degree 4

control: room-temperature RF

control placement: room-temp

readout: dispersive

gate evidence: no published figure

codes: quantum_repetition

Technologies by layer — the machine's cell per layer

1 Qubit carrier	Transmon · primary ▣ Fig. 1b (20-qubit crystal QPU topology: computational qubits (blue) with tunable couplers (green)); §2 QPU Architecture ✅ tunable transmon; 20 qubits, deployed on Amazon Braket
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. 2 (circuit representation of the qubit-coupler-qubit unit); §2.2 Quantum gates; Fig. 8b (1QB/CZ error CDFs) ✅ tunable couplers, native CZ; native arbitrary X/Y 1Q rotations
4 Connectivity / transport	Static nearest-neighbour lattice · primary ▣ Fig. 1b (20-qubit square-lattice crystal topology); §2.1 Connectivity ✅ Crystal square lattice, degree 4
5 Control	Room-temperature electronics + per-qubit coax/flex · primary ▣ Fig. 4 (cryogenic components inside the host dilution refrigerator); Fig. 6 (subrack of IQM QCS electronics); §3.2 QPU control electronics; §2.5 Control routing ✅ room-temperature RF control
6 Readout	Dispersive microwave readout (+TWPA, Purcell) · primary ▣ Fig. 3 (designed readout circuit: S21 and impedance vs frequency, target modes); §2.3 Qubit readout; Fig. 8b (RO error CDF) ✅ dispersive readout; no Garnet-specific readout figure
7 Code	— none — nothing in this layer ▥ 🔎 no code run on IQM hardware (L0/L1); NISQ device
8 Decoder	— none — nothing in this layer ▥ 🔎 no decoder; no QEC run
9 Interconnect	— none — nothing in this layer ◌ 🔎 monolithic single 20-qubit module, no interconnect
10 Manufacturing	Superconducting-qubit lithography (Al/AlOx/Al junctions, Nb wiring, 300 mm) · primary ▤ §2.5 Control routing and fabrication ✅ superconducting-qubit fab (IQM); no machine-specific fab source

evidence: ✅ 6 / 10

Pictures

Every picture carries the story of what it shows and its credit line.

Fig. 3 — NL-based benchmarking using LR-QAOA for WMC problems; (a) QPU layouts used in each experiment — Three-panel paper figure made of drawings and data plots, from an arXiv paper by J. A. Montanez-Barrera, Kristel Michielsen and David E. Bernal Neira (2025-05-28) on benchmarking processors with linear-ramp QAOA. Panel (a) draws the qubit coupling graphs of 5-, 20-, 127-, 133- and 156-qubit processors, including IBM Heron devices; panels (b) and (c) plot approximation ratio against the number of QAOA layers. Notice the fixed nearest-neighbour lattices: the sparse heavy-hex patterns versus the denser square lattice limit which qubits can interact directly. “Fig. 3 — NL-based benchmarking using LR-QAOA for WMC problems; (a) QPU layouts used in each…” by J. A. Montanez-Barrera, Kristel Michielsen, David E. Bernal Neira, arxiv.org/abs/2502.06471, CC BY 4.0 (creativecommons.org/licenses/by/4.0/)

File:IQM Quantum Computer Espoo Finland.jpg — Photograph of an open dilution-refrigerator insert (the 'chandelier') with its shields and vacuum cans removed: gold-plated stage plates hanging from a large top flange, each carrying rows of semi-rigid coaxial lines with coiled strain-relief loops, and flexible coax cables dangling below. Taken by Ragsxl (2020) and captioned 'IQM Quantum Computer in Espoo Finland'. It shows how many separate coaxial lines run from room temperature down through ever colder stages to the quantum chip, a wiring load that grows with every added qubit. “IQM Quantum Computer Espoo Finland” by Ragsxl, commons.wikimedia.org/wiki/File:IQM_Quantum_Computer_Espoo_F…, CC BY SA 4.0 (creativecommons.org/licenses/by-sa/4.0/)

File:IQM Jeffrey Chan.jpg — Photograph of an open dilution-refrigerator insert (the 'chandelier', radiation shields removed) beside an engineer touching its bottom cables with a gloved hand. The caption names him as IQM quantum engineer Jeffrey Chan; the photo was taken by Ragsxl in 2020. Notice the stacked gold-plated temperature-stage plates and the dense curtain of coaxial lines running down through them: each superconducting qubit needs its own control and readout lines from room-temperature electronics, and this wiring fills much of the fridge. “IQM Jeffrey Chan” by Ragsxl, commons.wikimedia.org/wiki/File:IQM_Jeffrey_Chan.jpg, CC BY SA 4.0 (creativecommons.org/licenses/by-sa/4.0/)