Logical quantum processor based on reconfigurable atom arrays

Area of Science:

• Quantum Information Science
• Quantum Computing
• Quantum Error Correction

Background:

• Suppressing errors is critical for useful quantum computing, necessitating quantum error correction (QEC).
• The overhead of error-corrected logical qubits presents a major hurdle for large-scale quantum computation.
• Existing quantum processors face challenges in achieving high fidelities and scalability for QEC.

Purpose of the Study:

• To realize a programmable quantum processor utilizing encoded logical qubits.
• To demonstrate improved quantum error correction capabilities and algorithmic performance.
• To overcome the overhead challenges associated with logical qubit realization.

Main Methods:

• Development of a programmable quantum processor with up to 280 physical qubits using neutral-atom arrays.
• Implementation of logical-level control, zoned architecture, and arbitrary connectivity.
• Utilization of various encoding schemes, including surface codes and color codes, for error correction.

Main Results:

• Demonstrated improvement in two-qubit gate fidelity by scaling surface code distance.
• Achieved break-even fidelities for color-code qubits and fault-tolerant creation of logical GHZ states.
• Successfully executed complex sampling circuits with up to 48 logical qubits, outperforming physical qubit fidelities.

Conclusions:

• The developed logical quantum processor significantly enhances algorithmic performance with error detection.
• This work marks a significant step towards early error-corrected quantum computation.
• The findings provide a clear pathway for the development of large-scale logical quantum processors.