IBM Quantum Egret

IBM · superconducting circuits · RETIRED (launched 2022) · 33 physical qubits · access: lab/cloud (historical)

qubit type: fixed-frequency transmon

gate mechanism: first IBM flux-tunable couplers, native CZ

connectivity: heavy-hex

control: room-temperature RF

control placement: room-temp

readout: multiplexed dispersive

gate evidence: no published figure

flags: source not confirmed

1 Qubit carrier	Transmon · primary ▦ 🔎 fixed-frequency transmon + flux-tunable couplers; 33 q (DEPLOYED 2022, now RETIRED)
2 Encoding	Bare physical qubit (no encoding) · primary ◌ 🔎 Bare two-level subspace — Computational subspace of an anharmonic oscillator; leakage to \|2⟩ is the price.
3 Gate mechanism	Tunable-coupler CZ / iSWAP · primary ▥ §Heron ('Heron is an Eagle-sized upgrade to Egret'; Osprey signal-delivery innovations) ✅ first IBM flux-tunable couplers, native CZ; coupler bridge from CR to Heron
4 Connectivity / transport	Static nearest-neighbour lattice · primary ▦ 🔎 heavy-hex, degree ≤3; 33 q
5 Control	Room-temperature electronics + per-qubit coax/flex · primary ▦ 🔎 room-temperature RF
6 Readout	Dispersive microwave readout (+TWPA, Purcell) · primary ◌ 🔎 multiplexed dispersive
7 Code	— none — nothing in this layer ▦ 🔎 no QEC code run; NISQ device
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 (Nb/Al JJ)

evidence: ✅ 1 / 10