Generating Greenberger-Horne-Zeilinger States in Remote Trapped Ions

Quantum networks promise ultra-secure lines of communications that are both tamper proof and tamper evident. Remote entanglement, the required first-step towards a quantum network, has been demonstrated in a number of systems. Here we describe a protocol to extend two-qubit remote entanglement to generate a Greenberger-Horne-Zeilinger (GHZ) state comprising three remote trapped-ion qubits. Two-particle remote entanglement combined with local operations and communication of classical bits can generate large-scale, network-sized, multi-particle entanglement for distributing quantum information. Quantum communication channels are desirable as they may enable secure links that could reveal the presence of eavesdroppers and protect critical information.