Rigetti

Rigetti Computing builds and deploys integrated quantum computing systems leveraging superconducting qubit technology. These systems enable organizations to augment existing computational workflows with quantum processors. Rigetti serves customers in finance, insurance, pharmaceuticals, defense, and energy with custom software and full-stack solutions focused on simulation, optimization, and machine learning applications. The company is headquartered in California, with offices in Australia and the UK.

“Providing AWS customers access to Rigetti QPUs is an important part of accelerating the commercialization of quantum computing. Our AWS collaboration enables end users to develop quantum algorithms using our state-of-the-art quantum hardware, enabling a wide range of application and research progress that will guide the industry forward.”

Dr. Subodh Kulkarni, CEO of Rigetti Computing

Rigetti quantum processors are universal, gate-model machines based on tunable superconducting qubits. Universal, gate-based quantum computers can have applications in areas including chemical simulation, combinatorial optimization, and machine learning. Because coherent superconducting qubits operate on the same quantum mechanical principles that govern nature, they can be used to efficiently simulate and understand the behavior of biochemical mechanisms, for example photosynthesis and protein folding. In addition, quantum computers can be used to navigate exponentially more state space to find more optimal solutions among an incalculable set of possibilities, for example in global logistics management.

Rigetti processors consist of three principal subsystems. First, user programs are optimized into machine-native instructions through a compiler tool chain. Then, a low-latency hardware controller sequences these instructions as calibrated electrical signals. Finally, the qubits, made from coherent superconducting circuit elements, transduce these electrical signals logically as digital quantum gates and measurement instructions. 

Cepheus™-1-108Q is Rigetti's largest quantum processing unit (QPU) to-date. Based on Rigetti's proprietary multi-chip architecture, Cepheus™-1-108Q consists of a 3x4 array of twelve 9-qubit chiplets tiled together, each containing a square lattice of qubits with tunable couplers and intermodule couplers (IMCs) between chiplets.

Beginning with Cepheus, the qubits on Rigetti QPUs are optimized for CZ (controlled phase) gates. In contrast to previously used iSWAP gates on previous Rigetti QPUs, CZ gates are more resilient to phase error, common in superconducting systems, resulting in increased fidelity. Further, Rigetti qubits specifically implement adiabatic CZ, a technique that increases resilience to leakage errors and improves gate fidelity. Performance metrics for current Rigetti systems, including gate fidelities and coherence times, can be found on Rigetti's QPU page.