Quantum/Machines/IBM Loon
USA · operational · Superconducting circuits
IBM Loon
IBM Loon is a superconducting circuits quantum computer operated by IBM in USA. Its physical qubit count has not been published. 5 sourced specs are in the spec sheet. 1 published benchmark or milestone record are listed below, each marked by who measured it.
Also known as IBM Quantum Loon
Experimental IBM processor announced 12 November 2025 as a testbed for qLDPC error-correction components, including long-range on-chip connections and qubit reset. IBM says it was announced with real-time qLDPC decoding in under 480 nanoseconds on classical hardware. The sources consulted do not give a qubit count for Loon, and it is not offered on the IBM cloud. It is a stepping stone toward IBM's planned Kookaburra (2026) and Starling (2029) systems.
Spec sheet
Technical details as the builder or a paper states them, each with its own source. A blank is a fact we could not source, not a zero. Fidelity and coherence figures are in the benchmark table below.
| Spec | Value | Basis | Note | Source |
|---|---|---|---|---|
| Processor | Loon, experimental processor for qLDPC error correction | Vendor reported | IBM says Loon shows the key processor components for fault-tolerant computing; no qubit count was given in the sources consulted. | newsroom.ibm.comquantumcomputingreport.com |
| Topology | Multiple low-loss routing layers giving c-couplers: long-range on-chip links beyond nearest neighbours | Vendor reported | IBM says c-couplers physically link distant qubits on the same chip and the chip includes qubit reset between computations. | newsroom.ibm.comnextplatform.com |
| Fabrication | IBM wafers at NY Creates Albany NanoTech Complex, 300 mm fab, New York | Vendor reported | Company-wide statement that primary quantum wafer fabrication is at Albany; the release does not name Loon specifically. | newsroom.ibm.comquantumcomputingreport.com |
| Successor | Kookaburra | Vendor reported | IBM roadmap places Kookaburra (2026) after Loon (2025), then Cockatoo (2027) and Starling (2029). | ibm.comspectrum.ieee.org |
| Roadmap | Kookaburra in 2026, Cockatoo in 2027, Starling fault-tolerant system in 2029 | Vendor reported | IBM roadmap blog of June 2025; the November 2025 release confirms Loon and the 2029 fault-tolerant target. | ibm.comthequantuminsider.com |
Milestone claims
- IBM, announcing Loon, claimed real-time qLDPC decoding in under 480 ns on classical hardware, a 10x speedup over leading approaches. (2025-11-12, vendor reported) quantumcomputingreport.comnextplatform.com
Timeline
- 2025-11-12: Announced
- 2025-11-12: Status checked: operational
More from IBM
- IBM Eagle (decommissioned, 127 qubits)
- IBM Osprey (decommissioned, 433 qubits)
- IBM Condor (operational, 1,121 qubits)
- IBM Heron (operational, 156 qubits)
- IBM Nighthawk (operational, 120 qubits)
- IBM Quantum System Two (Yorktown Heights) (operational)
- IBM Quantum Starling (planned)
- IBM Quantum System Two (Chicago) (under construction, 156 qubits)
Comparable superconducting machines
Closest in physical qubit count within the same technology. Counts of different qubit types are not interchangeable across technologies.
| Machine | Operator | Qubits | Status |
|---|---|---|---|
| Euro-Q-Exa | LRZ | 54 | operational |
| ORNL Pathfinder | Oak Ridge National Laboratory | 20 | operational |
| Rigetti Cepheus-1-108Q | Rigetti Computing | 108 | operational |
| Origin Wukong-180 | Origin Quantum | 180 | operational |
| IQM Radiance NOX at CINECA | CINECA | 54 | operational |
| IQM Radiance at Poznan University of Technology | Poznan University of Technology | - | operational |