High-Fidelity Universal Gate Set for ^{9}Be^{+} Ion Qubits.

Area of Science:

• Quantum Information Science
• Atomic Physics
• Quantum Computing

Background:

• Achieving high-fidelity quantum operations is crucial for building scalable quantum computers.
• Developing robust qubits that are less susceptible to environmental noise is a key challenge.

Purpose of the Study:

• To demonstrate high-fidelity laser-induced quantum logic gates on magnetic-field-insensitive qubits.
• To characterize the performance of single- and two-qubit gates and assess their potential for fault-tolerant quantum computation.

Main Methods:

• Utilized hyperfine states in beryllium-9 (Be+) ions as qubits.
• Employed laser-beam-induced operations for implementing quantum logic gates.
• Measured qubit coherence times and gate fidelities using established quantum information protocols.

Main Results:

• Achieved a memory coherence time exceeding 1 second for the beryllium ion qubits.
• Demonstrated single-qubit gates with an error rate of 3.8(1)×10⁻⁵.
• Deduced a two-qubit gate error of 8(4)×10⁻⁴ by creating a Bell state.

Conclusions:

• The implemented quantum logic gates exhibit high fidelity, suitable for advanced quantum information processing.
• The results indicate a viable pathway towards fault-tolerant quantum computation using trapped ion qubits.
• Further error characterization and mitigation strategies are discussed for improved performance.