A quantum-logic gate between distant quantum-network modules

The big challenge in quantum computing is to realize scalable multi-qubit systems with cross-talk-free addressability and efficient coupling of arbitrarily selected qubits. Quantum networks promise a solution by integrating smaller qubit modules to a larger computing cluster. Such a distributed architecture, however, requires the capability to execute quantum-logic gates between distant qubits. Here we experimentally realize such a gate over a distance of 60 meters. We employ an ancillary photon that we successively reflect from two remote qubit modules, followed by a heralding photon detection, which triggers a final qubit rotation. We use the gate for remote entanglement creation of all four Bell states, Our nonlocal quantum-logic gate could be extended both to multiple qubits and many modules for a tailor-made multi-qubit computing register.

Automated summary

The big challenge in quantum computing is to achieve scalable multi-qubit systems with cross-talk-free addressability and efficient coupling of arbitrarily selected qubits. Integrating smaller qubit modules to a larger computing cluster through quantum networks promises a solution. Researchers have successfully demonstrated a quantum-logic gate over a distance of 60 meters, allowing for remote entanglement creation and potential extension to multiple qubits and modules.