Key enhancements in the new system include a proprietary chiplet-based architecture that replaces monolithic chips. Credit: Below the Sky/Shutterstock.com.
Rigetti Computing, a US-based firm specialising in quantum technology, has announced the general availability of its 36-qubit multi-chip system, Cepheus-1-36Q.
The system is now accessible on Rigetti Quantum Cloud Services (QCS) and will soon be available on Microsoft Azure.
According to Rigetti, this machine features the largest number of chiplets ever integrated into a quantum computer, leveraging four separate chips.
The Cepheus-1-36Q system is claimed to deliver a 2x reduction in two-qubit gate error rate compared to its predecessor, the Ankaa-3 system. It achieves a median two-qubit gate fidelity of 99.5%.
Key enhancements in the new system include a proprietary chiplet-based architecture that replaces monolithic chips. This approach yields better chip uniformity and performance through reduced manufacturing complexity and improved fabrication yield.
Rigetti stated that optimised two-qubit gates contribute to faster gate times while reducing coherent errors, enhancing overall fidelity which is critical for executing quantum error correction. The company said that these technological improvements have facilitated its goal of introducing a 100+ qubit system by the end of 2025 with similar fidelity metrics.
Rigetti CEO Subodh Kulkarni said: “It’s our view that superconducting qubits are the leading modality for quantum computers due to their ability to scale, and their ability to achieve gate speeds more than 1,000 times faster than other modalities like ion traps and pure atoms.
“Rigetti’s superconducting qubits leverage technologies, like chiplets, that have been maturing in the semiconductor industry for decades, enabling Rigetti to use well-established methods to scale to higher performance and qubit counts.”
Last month, Rigetti announced it had reached its mid-year performance milestone of 99.5% median two-qubit gate fidelity with its modular 36-qubit system, doubling the error reduction seen in their previous single-chip Ankaa-3 system. This 36-qubit setup comprises four 9-qubit chiplets and represents an essential step towards the company’s larger objectives.
Financially, Rigetti reported a net loss of $39.7m for the second quarter ending 30 June 2025, with total revenues reaching $1.8m for the same period.
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