Quantum/Machines/Rigetti Cepheus-1-108Q
USA · operational · Superconducting circuits
Rigetti Cepheus-1-108Q
Rigetti Cepheus-1-108Q is a superconducting circuits quantum computer operated by Rigetti Computing in USA. It has 108 physical qubits. It ranks 18 of 43 superconducting machines in this table by physical qubit count. 12 sourced specs are in the spec sheet. 2 published benchmark or milestone records are listed below, each marked by who measured it.
Also known as 108-qubit multi-chip system
Rigetti's largest system, generally available from April 2026 through Rigetti's cloud and Amazon Braket. Rigetti reports 99.1 percent median two-qubit fidelity and expects 99.5 percent later in 2026; that target is not yet demonstrated. It was delayed from an earlier end-2025 plan.
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 | Cepheus-1-108Q: twelve interconnected 9-qubit chiplets | Vendor reported | Rigetti general availability release of 7 April 2026; the second source restates the same release. | thequantuminsider.comquantumcomputingreport.com |
| Qubit type | All-tunable superconducting qubits with tunable couplers | Independent | AWS describes Rigetti processors as all-tunable superconducting qubits (family-wide); Rigetti says it refined its tunable coupler design for this system. | docs.aws.amazon.comthequantuminsider.com |
| Topology | Square lattice tiled from twelve 9-qubit chiplets | Independent | qBraid renders Rigetti devices from a square-lattice config; the chiplet count comes from Rigetti, so the exact inter-chiplet layout is not stated. | docs.qbraid.comthequantuminsider.com |
| Couplers | 193 | Independent | Calibrated two-qubit edges in qBraid live coupling map, which lists 107 qubits for this 108-qubit system; the count can change with each calibration. | docs.qbraid.com |
| Native gates | RX (angles +/- pi/2 and +/- pi only), RZ, CZ | Independent | qBraid documents the device ISA (RX, RZ, CZ, I, MEASURE); Rigetti says it uses an adiabatic CZ scheme on this system. | docs.qbraid.comthequantuminsider.com |
| Two-qubit gate time | 60 ns | Vendor reported | Rigetti states a gate speed of about 60 ns at general availability; a 28 ns adiabatic CZ at 99.9 percent fidelity was shown only on a prototype system. | thequantuminsider.comquantumcomputingreport.com |
| Fabrication | Rigetti, using Alternating-Bias Assisted Annealing for qubit frequency targeting | Vendor reported | The release credits Rigetti advanced fabrication process and does not name the fab site. | thequantuminsider.com |
| Software | Quil via pyQuil and quilc (Quil-T for pulse level), QIR, Amazon Braket SDK | Independent | Azure Quantum accepts Quil and QIR jobs for this target; Braket documents pulse-level control on Rigetti devices. | learn.microsoft.comdocs.aws.amazon.com |
| Cloud platforms | Amazon Braket; Microsoft Azure Quantum | Independent | Both AWS and Microsoft list Cepheus-1-108Q as an available target; Rigetti Quantum Cloud Services also offers it directly. | docs.aws.amazon.comlearn.microsoft.com |
| Access and pricing | Cloud queue or reservation; Braket price $0.30 per task + $0.000425 per shot, $4,100 per hour reserved | Independent | Braket price is listed for the Rigetti Cepheus family in us-west-1 as of October 2026; qBraid bills direct QCS access per minute of execution. | aws.amazon.comthequantuminsider.com |
| Predecessor | Rigetti Cepheus-1-36Q | Vendor reported | Release says the system triples the qubits and chiplets of the 36-qubit Cepheus-1-36Q. | thequantuminsider.comquantumcomputingreport.com |
| Roadmap | Expects 99.5% median two-qubit fidelity later in 2026 and a roadmap update; quantum advantage targeted in about three years | Vendor reported | Stated by Rigetti on 7 April 2026; the 99.5 percent target is not yet demonstrated on this system. | thequantuminsider.comquantumcomputingreport.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 |
|---|---|---|---|---|---|
| Single-qubit gate fidelity | 99.9% | 2026-04 | Vendor reported | Median single-qubit gate fidelity at general availability | globenewswire.comthequantuminsider.com |
| Two-qubit gate fidelity | 99.1% | 2026-04 | Vendor reported | Median two-qubit gate fidelity at general availability; Rigetti expects 99.5% later in 2026 | globenewswire.comthequantuminsider.com |
Timeline
- 2026-04-07: Announced
- 2026-04: First operational
- 2026-10: Status checked: operational
More from Rigetti Computing
- Rigetti Ankaa-3 (operational, 84 qubits)
- Rigetti Cepheus-1-36Q (operational, 36 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 |
|---|---|---|---|
| Zuchongzhi 3.2 | USTC | 107 | operational |
| Google Willow | Alphabet | 105 | operational |
| Zuchongzhi 3.0 | USTC | 105 | operational |
| IBM Nighthawk | IBM | 120 | operational |
| IBM Eagle | IBM | 127 | decommissioned |
| University of Tokyo IBM Quantum System One | University of Tokyo | 127 | operational |