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Cepheus-1-36Q

Name: Cepheus-1-36Q specifications
Creator: QPU137

Cepheus-1-36Q is a superconducting gate-based processor by Rigetti with 36 qubits (2025). 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 device Compare

Measurement records6 disclosed · 2 not disclosed · 2 sources

Select a figure to open its record

Qubit count (qubit_count_physical)36 qubitsvendor claim

Vendor claim

Source: Rigetti Q2 2025 press release and rigetti.com/what-we-build ('Qubits 36') · published 2025-08-12
Method: VENDOR_UNSPECIFIED
Notes: Four 9-qubit chiplets.
Citation key: [rigetti/cepheus-1-36q:qubit-count-physical:2026-08-19]

Two-qubit gate quality (two_qubit_gate_fidelity)99.5 %vendor claim

Vendor claim

Source: Rigetti Q2 2025 press release (2025-08-12) and rigetti.com/what-we-build spec table (fetched 2026-08-19 session) · published 2025-08-12
Method: not stated ('achieving a median two-qubit gate fidelity of 99.5%'); what-we-build table: 'Median Fidelity (per op.) — Two-qubit gates (CZ) 99.5%'
Aggregation: median
Notes: PR frames this as a '2x reduction in two-qubit gate error rate from its previous Ankaa-3 system'. Rigetti's Jan 9, 2026 press release later reported '99.6% on our 36-qubit system' (median 2Q); the current what-we-build snapshot still shows 99.5%. Values are from different dates, so recorded as an update note rather than CONFLICTING.
Citation key: [rigetti/cepheus-1-36q:two-qubit-gate-fidelity:2026-08-19]

Single-qubit gate quality (one_qubit_gate_fidelity)99.9 %vendor claim

Vendor claim

Source: rigetti.com/what-we-build QPU table
Method: VENDOR_UNSPECIFIED
Aggregation: median (per op.)
Citation key: [rigetti/cepheus-1-36q:one-qubit-gate-fidelity:2026-08-19]

Coherence (T1)32 µsvendor claim

Vendor claim

Source: rigetti.com/what-we-build QPU table
Method: VENDOR_UNSPECIFIED
Aggregation: median ('Median Time Duration (µs)')
Citation key: [rigetti/cepheus-1-36q:t1:2026-08-19]

Coherence (T2)18 µsvendor claim

Vendor claim

Source: rigetti.com/what-we-build QPU table
Method: VENDOR_UNSPECIFIED
Aggregation: median ('Median Time Duration (µs)')
Citation key: [rigetti/cepheus-1-36q:t2:2026-08-19]

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: Q2 2025 GA press release (fetched in full), rigetti.com/what-we-build, Jan 2026 and Apr 2026 press releases
Notes: No device-specific 2Q gate time published. Company-level statement in Jan 9, 2026 PR: 'Current Rigetti quantum computing systems achieve gate speeds of 50-70ns.'

Readout (readout_fidelity)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: Q2 2025 GA press release, rigetti.com/what-we-build, qcs.rigetti.com/qpus (JavaScript SPA, no static content)

Deployment date (deployment_date)2025-08-12 ('Cepheus-1-36Q was deployed on August 12, 2025', matching GA announcement date)vendor claim

Vendor claim

Source: rigetti.com/what-we-build
Method: VENDOR_UNSPECIFIED
Citation key: [rigetti/cepheus-1-36q:deployment-date:2026-08-19]

Topology

square-lattice — Four 9-qubit chiplets tiled together (multi-chip / chiplet architecture with intermodule couplers); chiplets use Rigetti's square lattice of qubits with tunable couplers. Vendor: 'with four chips, contains the largest number of chiplets in a quantum computer' (at Aug 2025).

SOURCE: Rigetti Q2 2025 results press release — 'Announces General Availability of its 36-Qubit Multi-Chip Quantum Computer'

Native gate set

1q —
2q CZ

SOURCE: rigetti.com/what-we-build QPU table labels the two-qubit fidelity entry 'Two-qubit gates (CZ)'; 1-qubit native set not published for this device

Cloud access

Rigetti Quantum Cloud Services (QCS) — GA announced 2025-08-12
Microsoft Azure Quantum — vendor PR said 'available on Microsoft Azure thereafter'; not present in Azure's Rigetti target table as of page updated 2026-04-10 (only Cepheus-1-108Q listed)

Corrections

Found an error in this data? Report it — every report is logged publicly, whether or not it turns out to be right.

QPU137 is independent and is not affiliated with, endorsed by, or sponsored by Rigetti. Figures above are public disclosures recorded with their sources on 2026-08-19; vendor claims are labeled as such and may not be directly comparable across measurement methods — see methodology.