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Quantinuum System Model H1 (H1-1)

Quantinuum System Model H1 (H1-1) is a trapped ion gate-based processor by Quantinuum with 20 qubits (2020). Below: every publicly disclosed figure with its source, method, and vendor-claim status — plus what is not disclosed, recorded as findings.

Data as of 2026-08-19Compile a circuit for this class of deviceCompare
Measurement records10 disclosed · 2 not disclosed · 5 sources
Select a figure to open its record
Qubit count (qubit_count_physical)20 qubitsvendor claim
Vendor claim
Method
VENDOR_UNSPECIFIED
Notes
Launched Oct 2020 with 10 qubits, upgraded to 20 fully connected qubits. Data sheet Table 1: Qubits = 20; five parallel two-qubit operations.
Citation key
[quantinuum/quantinuum-system-model-h1:qubit-count-physical:2026-08-19]
Two-qubit gate quality (two_qubit_gate_infidelity_spec)1e-3 (Typical), 3e-3 (Max) infidelityvendor claim
Vendor claim
Method
Not stated in data sheet table (machine-specific data referenced to Performance Validation document and hardware specifications GitHub repository)
Aggregation
Typical = most representative infidelity during machine operation, averaged over all operational zones; Max = upper bound during operation
Notes
Equivalent to typical 2Q gate fidelity 99.9%.
Citation key
[quantinuum/quantinuum-system-model-h1:two-qubit-gate-infidelit:2026-08-19]
Two-qubit gate quality (two_qubit_gate_infidelity_measured)9.7e-4 (+/- 6.2e-5) infidelityvendor claim
Vendor claim
Method
Two-qubit randomized benchmarking with random Clifford gates on qubit pairs
Aggregation
average (system-level measurement reported on vendor performance page)
Notes
Vendor-published characterization data; underlying raw data published in the Quantinuum hardware-specifications GitHub repository (github.com/CQCL/quantinuum-hardware-specifications).
Citation key
[quantinuum/quantinuum-system-model-h1:two-qubit-gate-infidelit:2026-08-19]
Two-qubit gate quality (two_qubit_gate_fidelity_milestone)99.914(3)% fidelityvendor claim
Vendor claim
Method
randomized benchmarking, on the commercially available device
Aggregation
across all qubit pairs
Notes
The 'three 9s' milestone announcement for H1-1.
Citation key
[quantinuum/quantinuum-system-model-h1:two-qubit-gate-fidelity-:2026-08-19]
Single-qubit gate quality (one_qubit_gate_infidelity)2e-5 (Typical), 2e-4 (Max); measured 1.8e-5 (+/- 2.9e-6) infidelityvendor claim
Vendor claim
Method
One-qubit randomized benchmarking with Clifford gates (performance validation page)
Aggregation
Typical = average over all operational zones (data sheet); measured value from performance validation page
Citation key
[quantinuum/quantinuum-system-model-h1:one-qubit-gate-infidelit:2026-08-19]
Spam error (spam_error)2e-3 (Typical), 5e-3 (Max); measured 1.22e-3 (|0>) / 3.43e-3 (|1>) error probabilityvendor claim
Vendor claim
Method
State preparation and measurement (SPAM) error
Aggregation
Typical average over operational zones (data sheet); per-state averages (performance validation)
Notes
Quantinuum publishes SPAM (combined state-prep + readout) rather than a separate readout fidelity.
Citation key
[quantinuum/quantinuum-system-model-h1:spam-error:2026-08-19]
Memory error (memory_error)2e-4 (Typical), 1e-3 (Max) error per qubit at average depth-1 circuitvendor claim
Vendor claim
Method
Memory error per qubit at average depth-1 circuit
Aggregation
Typical / Max as defined in data sheet
Notes
Also mid-circuit measurement cross-talk error: 4e-5 (Typical), 2e-4 (Max).
Citation key
[quantinuum/quantinuum-system-model-h1:memory-error:2026-08-19]
Coherence (T1_T2_coherence)not publicly disclosed
Not publicly disclosed — checked 2026-08-19
Finding
No public disclosure found. This is a recorded, dated finding — we do not substitute an estimate or borrow a figure from a sibling device.
Sources queried
H1 Product Data Sheet v8.0.1 (full 3 pages), Performance Validation page on docs.quantinuum.com, web search for Quantinuum H1 coherence times
Notes
Quantinuum specifies memory error per qubit at average depth-1 circuit instead of T1/T2 for H1.
Gate duration (two_qubit_gate_duration)not publicly disclosed
Not publicly disclosed — checked 2026-08-19
Finding
No public disclosure found. This is a recorded, dated finding — we do not substitute an estimate or borrow a figure from a sibling device.
Sources queried
H1 Product Data Sheet v8.0.1, Performance Validation page, Azure Quantum Quantinuum provider page
Notes
In QCCD machines wall-clock time is dominated by ion transport; no per-gate duration published in the data sheet.
Quantum volume (quantum_volume)1,048,576 (2^20) quantum volumevendor claim
Vendor claim
Method
IBM Quantum Volume protocol (as run by Quantinuum; data in vendor GitHub repositories)
Notes
At launch (October 2020) H1 had a measured quantum volume of 128 with 10 qubits (Honeywell press release, honeywell.com, Oct 2020).
Citation key
[quantinuum/quantinuum-system-model-h1:quantum-volume:2026-08-19]
Availability (availability_status)Retired from commercial service on October 15, 2025vendor claim
Vendor claim
Method
VENDOR_UNSPECIFIED
Notes
PCN: 'the H1-1 QPU, emulator, and syntax checker will be retired from commercial service on October 15th, 2025'; H1 PAYG plan removed from Azure Quantum; reason: 'With the 2025 release of the Helios quantum computer we have made the decision to sunset H1-1'. PDF served from https://docs.quantinuum.com/systems/_static/assets/pcns/... path.
Citation key
[quantinuum/quantinuum-system-model-h1:availability-status:2026-08-19]
Pricing model (pricing_model_exists)Yes - HQC (Hardware Quantum Credit) usage credits via monthly subscription and PAYG plans (Quantinuum direct and Azure Quantum)vendor claim
Vendor claim
Method
VENDOR_UNSPECIFIED
Notes
HQC formula published: HQC = 5 + C(N1q + 10*N2q + 5*Nm)/5000. H1 PAYG plan existed on Azure until retirement (per retirement PCN).
Citation key
[quantinuum/quantinuum-system-model-h1:pricing-model-exists:2026-08-19]