Quantinuum H1

Quantinuum H1 is a trapped ions quantum computer operated by Quantinuum in USA. It has 20 physical qubits. It ranks 9 of 15 trapped ion machines in this table by physical qubit count. 7 sourced specs are in the spec sheet. 3 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 H1, H1-1, H1-2

First-generation Quantinuum system, launched by Honeywell in October 2020 with 10 qubits and later upgraded to 20 fully connected qubits. Reached a quantum volume of 1,048,576 in April 2024. Quantinuum's system reference lists the H1 generation as sunset for international users on 2025-10-15; the successors are H2 and Helios, and RIKEN's Reimei belongs to the H1 family. 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 H1 linear surface-electrode QCCD trap with 198 DC electrodes	Vendor reported	Helios paper Table I lists 198 electrodes and 198 signals for H1; the 2021 QCCD paper describes a linear trap with 198 independently controlled DC electrodes.	arxiv.org arxiv.org
Qubit type	171Yb+ hyperfine clock-state qubits with 138Ba+ coolant ions	Peer reviewed	The H1-1 and H1-2 systems use 171Yb+ qubits, each paired with a 138Ba+ ion for sympathetic cooling.	arxiv.org arxiv.org
Topology	Single linear QCCD trap, all-to-all connectivity via ion transport, up to five parallel gate zones	Vendor reported	Product page states a single linear architecture with all-to-all connectivity; the 2022 paper describes five gate zones on H1-1 and three on H1-2.	quantinuum.com arxiv.org
Cooling and environment	Laser cooling (Doppler and resolved sideband) with sympathetic cooling by 138Ba+ ions in a vacuum chamber	Peer reviewed	Cooling protocols as described in the 2021 QCCD paper; these papers describe the H1 trap design, not a specific cloud unit.	arxiv.org arxiv.org
Access and pricing	Cloud subscription; international cloud instances sunset 2025-10-15, Japan unit Reimei continues	Vendor reported	Quantinuum Systems Reference lists H1 as Sunset (International) with release 2020-10-30 and sunset 2025-10-15.	docs.quantinuum.com
Predecessor	Quantinuum System Model H0	Peer reviewed	The H2 paper describes H0 and H1 as the first-generation hardware built around the same linear trap design.	arxiv.org
Successor	Quantinuum H2	Vendor reported	Systems Reference lists H2 (56 qubits, racetrack, released 2023-05-09) as the next hardware generation.	docs.quantinuum.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	1,048,576	2024-04-16	Vendor reported	QV 2^20 on H1-1, commercially available production machine	quantinuum.com quantinuum.com
Single-qubit gate fidelity	99.998%	2026-10	Vendor reported	Single-qubit gate fidelity as stated on the Quantinuum H1 product page	quantinuum.com
Two-qubit gate fidelity	99.914%	2024-04-16	Vendor reported	99.914(3) percent, repeatable across all qubit pairs on H1-1	quantinuum.com

Timeline

2020-10: Announced
2020-10: First operational
2026-10: Status checked: upgraded

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
Reimei	RIKEN	20	operational
AQT LRZ Ion-Trap System	LRZ	20	operational
PIAST-Q	PSNC	20	operational
IonQ Aria	IonQ	25	decommissioned
AQT IBEX Q1	AQT	12	operational
IonQ Forte	IonQ	36	operational