Quantum antennas for distributed neutral atom quantum networks

Recently, the reconfigurable neutral-atom array has attracted significant attention due to its full connectivity. While the single atom is excellent for high-fidelity quantum computing at local nodes, it poses a significant challenge for creating distributed entanglement in a quantum network due to its inherently weak atom-light coupling. In contrast, the atomic ensemble, which has a strong atom-light interaction due to the collective enhancement, is a good candidate for connecting the remote node. But their coherence time is short, and there are no practical local logical gates between ensembles so far, which excludes their use as local computing nodes. In this talk, we present a distributed quantum network architecture in which cold atomic ensembles with strong atom-light interactions serve as quantum antennas, interfacing single-atom qubits with flying photons to enable high-efficiency atom-photon entanglement generation — analogous to the role of antennas in classical communication. The leveraging of advantages of single atom and atomic ensemble results in an efficiency of $\eta \simeq 0.548$ for generating atom-photon entanglement, a probability of $P_{E} \simeq 6 \%$ for generating atom-atom entanglement, and a remote entanglement generation rate of $16.6 $ kHz, which can be further improved through system optimization. This performance not only surpasses that of state-of-the-art cavity-based or high-numerical-aperture-lens-based architectures but also offers notable advantages in simplicity, tunability, and experimental accessibility. Moreover, our scheme also integrates a long-lived quantum memory, providing a storage advantage for quantum repeater design.