IBM Quantum Blue Jay

Raveh Neeman

doi:10.5281/zenodo.22674814

IBM

IBM Quantum Blue Jay

IBM · superconducting circuits · PLANNED (2033+) · qubits not published · access: n/a

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

Register profile — the machine's variant of its architecture

qubit type: fixed-frequency transmon

gate mechanism: tunable coupler + l-couplers

connectivity: distributed across sites

control: room-temperature RF + cryo-CMOS

control placement: room-temp + cryo-CMOS

readout: dispersive

gate evidence: no published figure

decoder mode: planned — named in a roadmap only

codes: qcga

flags: cryogenic details missing

Technologies by layer — the machine's cell per layer

1 Qubit carrier	Transmon · primary ▦ 🔎 fixed-frequency transmon; 2,000 logical qubits, 10⁹ logical gates (PLANNED 2033+)
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 ▦ 🔎 tunable coupler + l-couplers (same technologies as Starling)
4 Connectivity / transport	Long-range on-chip couplers (c-couplers, mm-scale) · primary ▤ §1 Introduction (intra-module couplers tens of sites long; long-range inter-module couplers) ✅ l-coupled modules distributed across sites; 2,000 logical qubits, 10⁹ logical gates (PLANNED 2033+)
5 Control	Room-temperature electronics + per-qubit coax/flex · primary ▦ 🔎 room-temperature RF + cryo-CMOS (register; same technologies as Starling) Cryo-CMOS controller (4 K / mK) · alternate ▦ 🔎 cryo-CMOS alongside room-temperature RF (register; same technologies as Starling)
6 Readout	Dispersive microwave readout (+TWPA, Purcell) · primary ◌ 🔎 dispersive readout
7 Code	Non-local qLDPC codes (bivariate bicycle, 'gross') · primary ▣ Fig. 2 (module components: code c, LPU u, adapters); §2.1 Review of bivariate bicycle codes ✅ gross / bivariate-bicycle qLDPC memory blocks + LPUs (bicycle architecture); register codes gross;qcga Magic-state factory (cultivation / distillation / code switching) · alternate ▣ Fig. 2 (factory f, code-factory adapter a'); §2.5 T injections ✅ magic-state technology as in Starling technologies (code_qldpc + code_magic); register codes gross;qcga
8 Decoder	Relay-BP for qLDPC (FPGA) · primary ▣ Fig. 2 (Relay-BP FPGA decoder architecture); §4 Realization; §5 Resource utilization ✅ Relay-BP on FPGA/ASIC, intended in-loop; FPGA demo 24 ns/BP iteration, <1 µs avg per cycle on stored [[144,12,12]] syndromes
9 Interconnect	Multi-chip modules / l-couplers (same cryostat) · primary ▣ Fig. 2 (module connectivity: linear / triangular arrangements); §2.4 Inter-module measurements ✅ l-coupled cryogenic modules (same technologies as Starling); Blue Jay stated as distributed across sites
10 Manufacturing	Superconducting-qubit lithography (Al/AlOx/Al junctions, Nb wiring, 300 mm) · primary ◌ 🔎 Superconducting-qubit lithography (Nb/Al JJ, 300 mm) — IBM Albany 300 mm / Anderon foundry; Google Santa Barbara; Rigetti ABAA trimming (97.4% frequency-targeting success); OQC 500-qubit wafer-scale… 300 mm CMOS foundry (spins, cryo-CMOS, superconducting wiring) · alternate ◌ 🔎 fab_cmos as in Starling technologies (cryo-CMOS control); no Blue Jay-specific fab source

evidence: ✅ 5 / 13