High-Fidelity Distribution of Macroscopic Entanglement over Network of BEC Qubits

High-fidelity entanglement distribution is a crucial objective for various applications in quantum technologies, including quantum communication, distributed quantum computing, and quantum metrology. Current methods for that, mainly centered around quantum repeaters, focus on distributing only microscopic amounts of entanglement at a time. In this paper, we discuss a novel approach that was proposed for efficient distributing a macroscopic amount of entanglement across a chain of macroscopic Bose–Einstein condensates (BECs) or cold atomic ensembles. The framework employs BECs at each node, which are connected via a shared optical mode and enables the high-fidelity long-distance distribution of macroscopic entanglement while requiring only local measurements on the intermediate ensembles, the ensembles at the ends of the chain remain entangled, under ideal conditions without decoherence. We discuss that at specific “magic” interaction times the macroscopic entanglement can be distributed with perfect fidelity, regardless of the chain length. It paves a way for development of quantum repeaters for macroscopic entanglement distribution.