Multispecies Trapped-Ion Node for Quantum Networking.

Area of Science:

• Quantum Information Science
• Atomic Physics
• Quantum Networking

Background:

• Trapped atomic ions are a promising platform for quantum information networks.
• Existing architectures require isolation between spectator qubits and photonic interface qubits for local and remote operations.
• Scalable quantum network nodes necessitate efficient methods for qubit isolation.

Purpose of the Study:

• To demonstrate a method for achieving isolation between different qubit types within a single ion trap node.
• To showcase the essential components for a scalable ion trap quantum network node.
• To enable simultaneous local and remote entanglement operations within a quantum network.

Main Methods:

• Co-trapping of ytterbium-171 (¹⁷¹Yb⁺) and barium-138 (¹³⁸Ba⁺) atomic ions in a single ion trap.
• Utilizing the collective motion of the co-trapped ions for entanglement.
• Entangling a ¹³⁸Ba⁺ qubit with an emitted visible photon.

Main Results:

• Successfully isolated spectator qubit memories (¹⁷¹Yb⁺) from photonic interface qubits (¹³⁸Ba⁺).
• Demonstrated entanglement of a mixed-species qubit pair via their collective motion.
• Achieved entanglement between a ¹³⁸Ba⁺ qubit and a photon.

Conclusions:

• Co-trapping different atomic ion species provides the required isolation for scalable quantum network nodes.
• This approach facilitates the integration of local and remote entanglement operations within a single quantum network node.
• The demonstrated techniques are key ingredients for building advanced ion trap quantum networks.