IBM Quantum Heron r1

Raveh Neeman

doi:10.5281/zenodo.22674814

IBM · superconducting circuits · RETIRED (ibm_torino retired 1 Apr 2026, IBM retired-QPU list) (Dec 2023) · 133 physical qubits · access: cloud service

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

Register profile — the machine's variant of its architecture

qubit type: fixed-frequency transmon + flux-tunable coupler

gate mechanism: native CZ, ZZ-free idling

connectivity: heavy-hex, mean degree 2.3

control: room-temperature RF, high-density flex

control placement: room-temp

readout: multiplexed dispersive

gate evidence: the vendor's datasheet or dashboard

codes: bacon_shor, google_dynamic_surface

flags: conflicting claims

Technologies by layer — the machine's cell per layer

1 Qubit carrier	Transmon · primary ▤ §III.7 (Heron) ✅ fixed-frequency transmon + flux-tunable coupler; 133 q monolithic (DEPLOYED Dec 2023)
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 ▤ §III.7; Table 5 (ibm_torino metrics) ✅ native CZ via flux-tunable coupler, ZZ-free idling; median CZ error 2.46×10⁻³ (r1, 2023)
4 Connectivity / transport	Static nearest-neighbour lattice · primary ▤ 🔎 heavy-hex, degree ≤3, mean 2.3; 133 q
5 Control	Room-temperature electronics + per-qubit coax/flex · primary ▤ §III.7 (Heron) ✅ room-temperature RF with high-density flex cabling
6 Readout	Dispersive microwave readout (+TWPA, Purcell) · primary ◌ 🔎 multiplexed dispersive; median readout error 4.81×10⁻² (r1)
7 Code	Rotated surface code (+ yoked variants) · primary ▤ abstract; results ✅ 3CX surface code d=2–4 up to 5 rounds interleaved with a Bacon–Shor patch; logical Bell state by lattice surgery (sweep 7 Oct 2026, source read)
8 Decoder	— none — nothing in this layer ▨ 🔎 no decoder; no QEC run
9 Interconnect	— none — nothing in this layer ◌ 🔎 monolithic single 133-q die; no interconnect in production
10 Manufacturing	Superconducting-qubit lithography (Al/AlOx/Al junctions, Nb wiring, 300 mm) · primary ◌ 🔎 IBM 300 mm Albany superconducting-qubit lithography; flip-chip + TSV + multi-level wiring

evidence: ✅ 4 / 10

Pictures

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

File:Keynote - Entering the Era of Quantum Utility (IBM Research) 06.png — A frame from a keynote video: a slide titled 'Tunable Coupler architecture – Performance' with a small render of an IBM Quantum processor, a line drawing of a heavy-hex qubit layout, and text comparing Eagle R3 with Heron R1. It comes from IBM Research's keynote 'Entering the Era of Quantum Utility' (IBM Quantum Summit 2023). It contrasts fixed-frequency cross-resonance (ECR) gates with tunable-coupler CZ gates on superconducting processors: notice Heron's 96 ns CZ versus Eagle's 537 ns ECR, allowing more gates despite a shorter mean T1. “Keynote - Entering the Era of Quantum Utility (IBM Research) 06” by IBM Research, commons.wikimedia.org/wiki/File:Keynote_-_Entering_the_Era_o…, CC BY 3.0 (creativecommons.org/licenses/by/3.0/)

File:Keynote - Entering the Era of Quantum Utility (IBM Research) 02.png — A frame from a stage video: a gloved hand holds a gold-coloured plate edged in silver, with screws, rows of holes and a small grey square die at its centre. It comes from IBM Research's keynote 'Entering the Era of Quantum Utility', dated 2023-12-05 and posted on Wikimedia Commons; the register links it to IBM Heron r1. It shows a processor package, the holder that carries the chip into the cryostat; notice how small the die is compared with the package and its many signal connections. “Keynote - Entering the Era of Quantum Utility (IBM Research) 02” by IBM Research, commons.wikimedia.org/wiki/File:Keynote_-_Entering_the_Era_o…, CC BY 3.0 (creativecommons.org/licenses/by/3.0/)

A photograph of a lit glass-walled cube in a dark industrial hall, with tall frosted-glass and silver housings inside and dark cabinets along one side. Taken by Christopher Tirrell for IBM and uploaded to Flickr on 23 February 2024, it is recorded as the first IBM Quantum System Two at IBM Research, Yorktown Heights, New York, holding three Heron processors plus control electronics. Notice that no quantum chip is visible: the tall housings enclose the dilution refrigerators and the cabinets hold electronics. “IBM Quantum System Two (photo 3)” by Christopher Tirrell for IBM, www.flickr.com/photos/ibm_research_zurich/53548205110/, CC BY ND 2.0 (creativecommons.org/licenses/by-nd/2.0/deed.en)