Universal Global Gates for a Fine-Structure Qubit in Strontium-88

Area of Science:

• Quantum Information Science
• Atomic Physics
• Quantum Computing

Background:

• Metastable atomic qubits offer scalability and error conversion advantages for quantum computers.
• Strontium-88's metastable fine-structure qubit is encoded between the 3P0 and 3P2 states.

Purpose of the Study:

• To demonstrate and characterize a high-fidelity quantum gate set for the strontium-88 metastable fine-structure qubit.
• To develop a novel state-resolved detection scheme for high-fidelity qubit loss detection.
• To leverage a stable ground state for midcircuit erasure conversion.

Main Methods:

• Implementation and characterization of single- and two-qubit gates.
• Development of a state-resolved detection scheme for fine-structure states.
• Utilizing fast destructive imaging for midcircuit erasure conversion.

Main Results:

• Achieved single-qubit gate fidelities of 0.993(1).
• Achieved two-qubit gate fidelities of 0.9945(6) after loss correction.
• Demonstrated high-fidelity qubit loss detection and midcircuit erasure conversion.

Conclusions:

• The strontium fine-structure qubit is a promising platform for near-term error-corrected quantum computers.
• The demonstrated gate set and detection scheme enhance qubit control and error management.
• This work provides unique scaling perspectives for quantum computing architectures.