Fluxonium: An Alternative Qubit Platform for High-Fidelity Operations.

Area of Science:

• Quantum Computing
• Superconducting Circuits
• Quantum Information Science

Background:

• Transmon qubits are the leading platform for superconducting quantum computers but require lower error rates for fault tolerance.
• Alternative superconducting qubits with improved error protection are gaining interest.
• Fluxonium qubits show promise due to large anharmonicity and long coherence times.

Purpose of the Study:

• To engineer a fluxonium-based quantum processor.
• To evaluate the performance of fluxonium qubits for quantum computation.
• To demonstrate a competitive alternative to the transmon qubit platform.

Main Methods:

• Engineering a fluxonium quantum processor with integrated qubit coherence, tunable frequency, and individual addressability.
• Implementing simple and fast gate schemes for single- and two-qubit operations.
• Characterizing qubit performance through gate fidelity measurements.

Main Results:

• Achieved average single-qubit gate fidelity of 99.97%.
• Reached two-qubit gate fidelity of up to 99.72%.
• Demonstrated high qubit coherence, fast tunability, and individual qubit control.

Conclusions:

• The engineered fluxonium quantum processor demonstrates performance competitive with state-of-the-art superconducting circuits.
• Fluxonium qubits represent a viable alternative platform for building large-scale, fault-tolerant quantum computers.
• This work highlights the potential of fluxonium qubits beyond the transmon system.