# Multi-Species Trapped Ion Node for Quantum Networking

## TL;DR

This paper demonstrates a scalable quantum network node using co-trapped different ion species, enabling local and remote entanglement with high isolation, crucial for quantum communication.

## Contribution

It introduces a multi-species ion trap node that achieves isolation and entanglement of different ion species for quantum networking applications.

## Key findings

- Successfully co-trapped $^{171}$Yb$^+$ and $^{138}$Ba$^+$ ions.
- Demonstrated entanglement of mixed species qubits via collective motion.
- Entangled $^{138}$Ba$^+$ ions with emitted photons.

## Abstract

Trapped atomic ions are a leading platform for quantum information networks, with long-lived identical qubit memories that can be locally entangled through their Coulomb interaction and remotely entangled through photonic channels. However, performing both local and remote operations in a single node of a quantum network requires extreme isolation between spectator qubit memories and qubits associated with the photonic interface. We achieve this isolation and demonstrate the ingredients of a scalable ion trap network node by co-trapping $^{171}$Yb$^+\ $ and $^{138}$Ba$^+\ $ qubits, entangling the mixed species qubit pair through their collective motion, and entangling the $^{138}$Ba$^+\ $ qubits with emitted visible photons.