Rigetti Announces General Availability of 108-Qubit System

Insider Brief

• Rigetti announced general availability of its 108-qubit Cepheus-1 system, its largest modular quantum computer to date.
• The system uses a chiplet-based architecture and is accessible via Rigetti QCS and Amazon Braket for enterprise and research use.
• Cepheus-1-108Q delivers improved gate fidelities and performance, with further enhancements planned as part of Rigetti’s roadmap.

PRESS RELEASE — Rigetti Computing, Inc. (Nasdaq: RGTI) (“Rigetti” or the “Company”), a pioneer in full-stack quantum-classical computing, today announced the general availability of its 108-qubit quantum computing system, Cepheus-1-108Q, now accessible to customers and partners via the Rigetti Quantum Cloud Services (QCS^®) Platform and through Amazon Braket, the quantum computing service by AWS.

Cepheus-1-108Q is Rigetti’s highest qubit-count system to date and the industry’s largest modular quantum computing system, based on Rigetti’s proprietary chiplet-based architecture. The system comprises twelve interconnected 9-qubit chiplets, tripling the number of qubits and chiplets from Rigetti’s previous 36-qubit system, Cepheus-1-36Q.

The system is currently performing at a 99.1% median two-qubit gate fidelity with a gate speed of ~60 ns and a 99.9% median single-gate fidelity. Rigetti is releasing Cepheus-1-108Q now in response to growing customer interest, and will continue to improve the system performance throughout 2026 as the Company advances on its roadmap.

“Cepheus-1-108Q is a milestone that validates our ambitious approach to scaling quantum computers,” said Dr. Subodh Kulkarni, Rigetti CEO. “Our proprietary chiplet-based architecture is paving the way toward higher fidelity, higher qubit systems that will ultimately enable fault-tolerant quantum computing.”

“We are proud of the progress we have made in delivering a system at this scale. The innovations we’ve developed while designing this system give us confidence in our vision and approach to building the next generation of quantum computers. We will continue to improve fidelity as we scale to higher qubit counts and deploy new systems as we reach important performance milestones while maintaining gate speeds that are roughly 1,000-10,000 times faster than other modalities such as trapped-ion and neutral-atom systems.”

“The addition of Cepheus-1-108Q to Amazon Braket gives our global customers another choice as they research quantum computing applications in materials science, optimization, and quantum simulation. As the first gate-based device on Braket with over 100 qubits, Cepheus-1-108Q delivers improved fidelities that allow customers to push to wider and deeper circuits,” said Eric Kessler, General Manager, Amazon Braket. “Rigetti was a launch partner for Amazon Braket, and we’re excited to deepen that relationship with this launch. With Cepheus-1-108Q, we bring the third generation of Rigetti devices to our customers, following Aspen and Ankaa. We remain committed to providing researchers and enterprises around the world with access to the latest quantum hardware.”

Key Technical Advancements

The new system features several significant engineering improvements designed to maintain fidelity and performance as qubit counts grow:

• Enhanced qubit and coupler design: Optimized chip design enables fast two-qubit gates and higher fidelity.
• CZ gates for error correction: Supports high-fidelity native gates and efficient circuit compilation necessary for quantum error correction and future fault-tolerant architectures. Rigetti achieved a two-qubit gate fidelity as high as 99.9% at 28 nanoseconds on a prototype system using a proprietary implementation of an adiabatic CZ gate scheme. These gates are already in use on Cepheus-1-108Q and will continue to improve as Rigetti incorporates those prototype learnings into larger systems.
• Upgraded control electronics: A newly engineered control system delivers superior signal-to-noise ratio for qubit readout.
• Advanced fabrication process: Rigetti’s Alternating-Bias Assisted Annealing technique improves qubit frequency targeting and reduces defects, contributing to higher fidelities.

During system development, Rigetti refined its architecture to mitigate coupling interactions between tunable couplers that become more pronounced beyond 100 qubits. These design improvements shifted the primary performance limitation from coupler behavior to coherence time, a key factor the Company continues to address through innovations in materials and fabrication.

Roadmap

Rigetti plans to continue to improve the fidelity of its individual chiplets and expects Cepheus‑1‑108Q to reach a median 99.5% two‑qubit gate fidelity later this year. Rigetti intends to update its technology roadmap later this year, once it has incorporated the results of this work, including how the Company plans to reach quantum advantage in about three years.

For more information on Amazon Braket, please visit https://aws.amazon.com/braket/.