Quantum/Machines/Quantinuum H2
USA · upgraded · Trapped ions
Quantinuum H2
Quantinuum H2 is a trapped ions quantum computer operated by Quantinuum in USA. It has 56 physical qubits. It ranks 4 of 15 trapped ion machines in this table by physical qubit count. 10 sourced specs are in the spec sheet. 6 published benchmark or milestone records are listed below, each marked by who measured it.
Deep dive: Quantinuum Helios: what the claims support
Also known as System Model H2, H2-1
Launched in May 2023 with 32 qubits and upgraded to 56 qubits in June 2024. Holds the highest quantum volume reported by Quantinuum (2^25, September 2025) and was the machine used for the 2025 certified randomness experiment. Available by subscription, Azure Quantum and the ORNL Quantum Computing User Program. The physical site of the cloud-accessed unit is not stated in the pages consulted.
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 | System Model H2 racetrack QCCD ion trap, 56 qubits | Peer reviewed | Racetrack trap with periodic boundary conditions, described in the 2023 Physical Review X paper and the Quantinuum user guide. | arxiv.orgdocs.quantinuum.com |
| Qubit type | 171Yb+ hyperfine qubits with 138Ba+ sympathetic coolant ions | Vendor reported | Data sheet states qubits are hyperfine states of 171Yb+; user guide adds 138Ba+ as the coolant ion. | docs.quantinuum.comdocs.quantinuum.com |
| Topology | Racetrack QCCD trap, all-to-all connectivity by ion transport, 4 parallel two-qubit operations | Vendor reported | Data sheet lists all-to-all connectivity and 4 parallel two-qubit operations; the user guide describes 8 gate zones, with state preparation and measurement in 4. | docs.quantinuum.comdocs.quantinuum.com |
| Native gates | Rxy rotations, virtual Rz, fully entangling ZZ, parameterized-angle Rzz, optional general SU(4) entangler | Vendor reported | Circuits are rebased to ZZ and Rzz by default; the SU(4) entangler is used only when requested at job submission. | docs.quantinuum.comdocs.quantinuum.com |
| Cooling and environment | Laser cooling of 138Ba+ coolant ions (Doppler sheet beams and sideband cooling) in a vacuum chamber | Peer reviewed | Coolant ions are cooled during transport and before two-qubit gates; no cryogenic stage is described. | arxiv.orgdocs.quantinuum.com |
| Software | pytket, qnexus, QIR, OpenQASM 2.0, Qiskit and Q# via Azure Quantum | Vendor reported | Quantinuum docs name QIR and OpenQASM 2.0 endpoints with pytket and qnexus examples; the Azure page documents Q# and Qiskit providers. | docs.quantinuum.comlearn.microsoft.com |
| Cloud platforms | Quantinuum direct access; Microsoft Azure Quantum; ORNL Quantum Computing User Program | Vendor reported | Product page lists the three routes; Azure lists H2-1 and H2-2 targets. | quantinuum.comlearn.microsoft.com |
| Access and pricing | Cloud subscription, direct or through Azure Quantum; US researchers can apply for QCUP credits | Vendor reported | Subscription and credit-grant routes per the product page; no price is published there. | quantinuum.comlearn.microsoft.com |
| Predecessor | Quantinuum H1 | Peer reviewed | H2 paper presents the racetrack trap as the first major trap design advance after the H-series linear trap. | arxiv.orgdocs.quantinuum.com |
| Successor | Quantinuum Helios | Vendor reported | Helios is described as building on H2 with nearly double the qubits and higher fidelity. | docs.quantinuum.comquantinuum.com |
Published benchmark figures
These are numbers the builder or a paper reports for this machine, not results from a common test. The basis column says who measured them. What the metrics mean and why they are not comparable across technologies.
| Metric | Value | Measured | Basis | Note | Source |
|---|---|---|---|---|---|
| Quantum volume | 33,554,432 | 2025-09-18 | Vendor reported | QV 2^25 on System Model H2, 4x the 8 million QV reported in May 2025 | quantumcomputingreport.comquantinuum.com |
| Single-qubit gate fidelity | 99.99% | 2026-10 | Vendor reported | Product page states greater than 99.99 percent; value is a lower bound | quantinuum.com |
| Two-qubit gate fidelity | 99.9% | 2026-10 | Vendor reported | Product page states greater than 99.9 percent; value is a lower bound | quantinuum.com |
Milestone claims
- Nature paper with Microsoft: logical error cut 11x to 800x versus physical baselines on H2, up to 12 logical qubits; some results use post-selection and no real-time decoding (2026-06, peer reviewed) quantum.microsoft.comnand-research.com
- Nature paper: certified randomness on H2-1 (56 qubits), 71,313 bits of entropy certified under restricted adversary assumptions (2025-03-26, peer reviewed) pmc.ncbi.nlm.nih.gov
- Quantinuum claimed random circuit sampling on 56-qubit H2-1 with XEB around 0.35, over 100x Google 2019 result (2024-06-05, vendor reported) prnewswire.com
Timeline
- 2023-05-09: Announced
- 2023-05: First operational
- 2026-10: Status checked: upgraded
More from Quantinuum
- Quantinuum H1 (upgraded, 20 qubits)
- Quantinuum Helios (operational, 98 qubits)
- Quantinuum Apollo (planned)
Comparable trapped ion machines
Closest in physical qubit count within the same technology. Counts of different qubit types are not interchangeable across technologies.
| Machine | Operator | Qubits | Status |
|---|---|---|---|
| IonQ Forte | IonQ | 36 | operational |
| IonQ Forte Enterprise at EPB | EPB | 36 | operational |
| IonQ Forte Enterprise at QuantumBasel | QuantumBasel | 36 | operational |
| Quantinuum Helios | Quantinuum | 98 | operational |
| IonQ Tempo | IonQ | 100 | operational |
| IonQ Aria | IonQ | 25 | decommissioned |