Random access quantum information processors using multimode circuit quantum electrodynamics.

Area of Science:

• Quantum Computing
• Superconducting Circuits
• Quantum Information Processing

Background:

• Qubit connectivity is crucial for quantum processor efficiency, with ideal processors allowing random access for arbitrary qubit interactions.
• Current superconducting quantum processor architectures are limited by nearest-neighbor coupling, hindering direct interaction between non-adjacent qubits.

Purpose of the Study:

• To implement a superconducting quantum information processor with random access capabilities.
• To demonstrate universal quantum operations and multi-qubit entanglement using this novel architecture.

Main Methods:

• Utilized a Josephson junction transmon circuit as the central processor for a nine-qubit memory based on coupled superconducting resonators.
• Stimulated vacuum Rabi oscillations between the transmon and individual resonator eigenmodes via parametric flux modulation.
• Performed universal quantum gates and prepared entangled states using only two control lines.

Main Results:

• Successfully demonstrated universal quantum operations on a nine-qubit memory.
• Achieved direct interaction and performed quantum gates on 38 arbitrary pairs of modes.
• Prepared multimode entangled states, showcasing hardware-efficient random access multi-qubit control.

Conclusions:

• The implemented random access superconducting quantum information processor overcomes the nearest-neighbor coupling limitation.
• This architecture is compatible with long-lived microwave cavity-based quantum memories.
• Achieved efficient multi-qubit control, advancing the development of scalable quantum computing hardware.