Rigetti's 84-qubit Ankaa-3 system

Ankaa-3 is Rigetti's newest flagship quantum computer featuring an extensive hardware redesign that enables superior performance. Enhancements across the technology stack include a new cryogenic hardware design, an overhaul of the qubit circuit layout, precise qubit frequency targeting with Alternating-Bias Assisted Annealing, and flexible gate architecture with precise controls. Photo Credit: Drew Bird Photography

Ankaa-3 features a broad hardware redesign enabling superior performance. Enhancements across the technology stack include a new cryogenic hardware design, an overhaul of the qubit circuit layout, precise qubit frequency targeting with Alternating-Bias Assisted Annealing, and flexible gate architecture with precise controls. Ankaa-3 has achieved a 99.5% median two-qubit gate fidelity.

BERKELEY, Calif., Dec.  23, 2024  (GLOBE NEWSWIRE) -- Rigetti Computing, Inc. (Nasdaq: RGTI) ("Rigetti" or the "Company"), a pioneer in full-stack quantum-classical computing, announced today the public launch of its 84-qubit Ankaa-3 system. Ankaa-3 is Rigetti's newest flagship quantum computer featuring an extensive hardware redesign that enables superior performance. Rigetti also celebrates major two-qubit gate fidelity milestones with Ankaa-3: successfully halving error rates in 2024 to achieve a median 99.0% iSWAP gate fidelity, as well as demonstrating 99.5% median fidelity fSim gates.

Ankaa-3 is now available to its partners via the Rigetti Quantum Cloud Services platform (QCS) and will be coming to Amazon Braket and Microsoft Azure in the first quarter of 2025. Users will be able to operate these higher fidelity and universal iSWAP gates for a wide range of algorithmic research, with a median gate time of 72 nanoseconds. The faster (median 56 nanoseconds), more specialized fSim gates are useful for specific algorithms such as random circuit sampling, as recently demonstrated on Google's Willow system.

The Ankaa-3 system continues to feature Rigetti's scalable, industry-leading chip architecture with 3D signal delivery while incorporating major enhancements to key technologies. Leveraging the Company's full-stack expertise and in-house quantum foundry capabilities, Ankaa-3 demonstrates Rigetti's ability to deliver increasingly higher performance quantum computers.

The Company's focus on improving qubit fidelity has resulted in enhancements across the technology stack:

• All new cryogenic hardware design - Reducing the amount of metal at the refrigerator's coldest stage increases efficiency and reduces the cost per qubit. Superior thermalization and magnetic/environmental shielding also improves system performance. This new design enables scaling up to thousands of qubits.

• Improved qubit chip - Rigetti overhauled its qubit chip, leading to improved coherence. Through its collaboration with the Superconducting Quantum Materials & Systems Center (SQMS) led by Fermilab, Rigetti implemented a metal deposition method for qubit circuitry with a higher T1 baseline -- which indicates the lifetime of a qubit. Additionally, the circuit layout was optimized to minimize qubit losses and take advantage of the new higher-coherence process.

• Josephson junction fabrication with Alternating-Bias Assisted Annealing (ABAA) - The Ankaa-3 chip features the hallmarks of Rigetti's Ankaa-class chip architecture with a square lattice of qubits and tunable couplers. The 84-qubit chip's Josephson junctions are manufactured using Rigetti's novel ABAA technique. ABAA allows for precise qubit frequency targeting, which enables better execution of two-qubit gates and increases in yield, both of which contribute to higher fidelity.

• Precise control and flexible gate architecture - Rigetti has invested heavily in the control technologies underpinning its QPUs. Chip-wide optimization of qubit and tunable coupler frequencies produces fewer unwanted qubit-qubit interactions, and real-time, in-hardware pulse pre-compensation produces gates with lower incoherent errors. Rigetti has also developed a robust calibration process for highly expressive square-root-iSWAP-like gates while solving some of the compilation challenges associated with their practical usage, resulting in an nQA-oriented gate set with significantly lower error rates.

"With approximately $225 million of cash, cash equivalents and available for sale investments and no debt, we are extremely confident in our ability to deliver on our roadmap and performance goals. The remarkable performance of Ankaa-3 reinforces our leadership in the superconducting quantum computing field -- which we believe is the winning modality for high-performance quantum computers due to their many advantages, including fast gate speeds and well-established manufacturing processes," says Dr. Subodh Kulkarni, Rigetti CEO.

"Our teams, across the technology stack, work incredibly hard to introduce new, innovative ways to increase our system's performance. As we continue the journey towards fault tolerance, we are constructing computing systems with capabilities that have not been seen before," says David Rivas, Rigetti CTO. "At Rigetti, working closely with our partners, we are committed to finding ways to put those systems to practical use."

Rigetti plans to introduce the next generation of its modular system architecture, while continuing to increase fidelities, in 2025. By mid-year 2025, the Company expects to release a 36-qubit system based on four 9-qubit chips tiled together, with a targeted 2x reduction in error rates from the current level. By the end of 2025, the Company expects to release a system with over 100 qubits with a targeted 2x reduction in error rates from the current level.

About Rigetti
Rigetti is a pioneer in full-stack quantum computing. The Company has operated quantum computers over the cloud since 2017 and serves global enterprise, government, and research clients through its Rigetti Quantum Cloud Services platform. In 2021, Rigetti began selling on-premises quantum computing systems with qubit counts between 24 and 84 qubits, supporting national laboratories and quantum computing centers. Rigetti's 9-qubit Novera QPU was introduced in 2023 supporting a broader R&D community with a high-performance, on-premises QPU designed to plug into a customer's existing cryogenic and control systems. The Company's proprietary quantum-classical infrastructure provides high-performance integration with public and private clouds for practical quantum computing. Rigetti has developed the industry's first multi-chip quantum processor for scalable quantum computing systems. The Company designs and manufactures its chips in-house at Fab-1, the industry's first dedicated and integrated quantum device manufacturing facility.