Rigetti Ships 108 Qubit Device.

Rigetti Computing has made its 108-qubit quantum computer, Cepheus-1-108Q, generally available to customers and partners through its Quantum Cloud Services platform and Amazon Braket. This new system represents the largest modular quantum computer to date, utilizing Rigetti’s chiplet-based architecture and tripling the qubit count of its previous generation. Cepheus-1-108Q currently achieves a 99.1% median two-qubit gate fidelity with a gate speed of approximately 60 nanoseconds, alongside a 99.9% median single-gate fidelity. “Cepheus-1-108Q is a milestone that validates our approach to scaling quantum computers,” said Dr. Subodh Kulkarni, Rigetti CEO, adding that the company’s architecture is enabling higher fidelity and higher qubit systems that will ultimately enable fault-tolerant quantum computing. Cepheus-1-108Q: 108-Qubit System & Modular Architecture Rigetti Computing’s unveiling of the Cepheus-1-108Q system marks a significant leap in quantum processor scale, boasting 108 qubits, the highest count currently available in a modular architecture. Unlike many approaches relying on monolithic silicon, Rigetti has constructed Cepheus-1-108Q from twelve interconnected 9-qubit chiplets, effectively tripling the qubit count and chiplet number from its prior 36-qubit system. This modular design is not simply about increasing qubit numbers; it’s a deliberate strategy to address the escalating challenges of maintaining fidelity as systems grow more complex. Rigetti is also releasing the hardware, making Cepheus-1-108Q accessible to researchers and developers through both the Rigetti Quantum Cloud Services platform and Amazon Braket, broadening access to this advanced quantum computing capability. Subodh Kulkarni, Rigetti CEO, emphasized the importance of this architectural validation. Several key engineering improvements underpin the system’s performance. Rigetti has focused on enhanced qubit and coupler design to accelerate two-qubit gates and improve fidelity, while also incorporating CZ gates, essential for error correction and the development of fault-tolerant quantum computers. The company achieved a two-qubit gate fidelity as high as 99.9% at 28 nanoseconds on a prototype system utilizing an adiabatic CZ gate scheme, and these advancements are already integrated into Cepheus-1-108Q. Upgraded control electronics deliver a superior signal-to-noise ratio for qubit readout, and an advanced fabrication process, utilizing Alternating-Bias Assisted Annealing, improves qubit frequency targeting and reduces defects. Rigetti refined its architecture to mitigate coupling interactions between tunable couplers, shifting the primary performance limitation from coupler behavior to coherence time, a factor the company continues to address through materials and fabrication innovations. 1% Fidelity with 60ns Gate Speed Performance The pursuit of stable, high-performing qubits remains central to realizing practical quantum computation, and recent advances demonstrate incremental but vital progress in overcoming inherent limitations. While numerous approaches to qubit design exist, superconducting qubits currently lead in gate speed, a critical metric for executing complex algorithms before quantum information is lost to decoherence. This performance is not simply about raw speed; maintaining high fidelity, the accuracy of quantum operations, as qubit counts increase is a substantial engineering challenge. The 108-qubit system’s architecture relies on twelve interconnected 9-qubit chiplets, a modular design intended to facilitate scaling without sacrificing performance. Rigetti has implemented several key improvements to maintain fidelity as qubit numbers grow, including enhanced qubit and coupler design optimized for fast gates and high accuracy. Subodh Kulkarni, Rigetti CEO, anticipates further improvements, aiming for a median 99.5% two-qubit gate fidelity later this year, and plans to unveil an updated technology roadmap incorporating these results. Maintaining these gate speeds, roughly 1,000 to 10,000 times faster than those of trapped-ion or neutral-atom systems, is considered vital for complex quantum computations. 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.Eric Kessler, General Manager, Amazon Braket Enhanced Chiplet Design & CZ Gate Implementation Rigetti Computing’s recent unveiling of the Cepheus-1-108Q system is not solely about increasing qubit count; it signals a deliberate shift in quantum computer architecture, prioritizing modularity and fidelity alongside scale. This approach allows for more manageable fabrication and testing, crucial as systems grow in complexity, and provides a pathway toward building even larger, more powerful quantum processors. Central to the performance gains of Cepheus-1-108Q are advancements in gate technology, specifically the implementation of CZ gates. The company’s commitment to improving fidelity extends beyond gate design, encompassing enhanced qubit and coupler design, upgraded control electronics, and an advanced fabrication process. 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.Eric Kessler, General Manager, Amazon Braket Rigetti’s Roadmap to 99.5% Fidelity & Quantum Advantage Rigetti’s ambitions extend beyond simply demonstrating a larger system; the company is actively focused on improving the reliability of quantum operations. A key focus for Rigetti is achieving higher fidelity, a measure of how accurately a quantum computer can perform calculations, and the company is targeting a median two-qubit gate fidelity of 99.5% later this year. This improvement is not merely incremental; it’s crucial for enabling more complex quantum algorithms and ultimately, fault-tolerant quantum computing. Beyond fidelity, Rigetti is also prioritizing maintaining gate speeds that are significantly faster than competing technologies. “We are proud of the progress we have made in delivering a system at this scale,” Kulkarni added, “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.” Rigetti anticipates releasing an updated technology roadmap later in the year, detailing how these advancements will contribute to achieving quantum advantage, the point at which a quantum computer can solve problems that are intractable for classical computers, within approximately three years. Cepheus-1-108Q is a milestone that validates our ambitious approach to scaling quantum computers.Dr. Subodh Kulkarni, Rigetti CEO Source: https://www.globenewswire.com/news-release/2026/04/07/3269628/0/en/Rigetti-Announces-General-Availability-of-108-Qubit-System.html Tags: