Yasunari Suzuki

To demonstrate quantum protocols on a global scale, a quantum repeater is a vital technology to improve the efficiency of entanglement distribution. Entanglement distribution consists of two steps; share entanglements between neighboring quantum repeaters, and perform entanglement distillation and swapping. In this paper, we propose a framework for the first step, efficient Bell measurement between adjacent quantum repeaters, using quantum memories based on cavity quantum electrodynamics (QED) systems. Our framework maximizes a distillable entanglement rate of the protocol by optimizing the parameters of a cavity QED system and pulse length of photons according to the number of available memories at repeater nodes. We demonstrate our theory with a nanofiber cavity QED system with trapped atoms, which is one of the most promising quantum devices for the quantum network. We show that with practical parameters, Bell measurements with quantum memories can outperform those without memories, and we show several trade-off relations between accessible parameters in experiments. Our results extend the limits of entanglement distribution with quantum repeaters using available technology, and reveal that the multiplexing of the cavity QED systems is effective for improving the performance of entanglement distribution.