Distributed Quantum Computing (DQC) enables scalability by interconnecting multiple QPUs. Among various DQC implementations, quantum data centers (QDCs), which utilize reconfigurable optical switch networks to link QPUs across different racks, are becoming feasible in the near term. However, the latency of cross-rack communications and dynamic reconfigurations poses unique challenges to quantum communication, significantly increasing the overall latency and exacerbating qubit decoherence. In this paper, we introduce a new optimization space to parallelize cross-rack communications and avoid frequent reconfigurations, which incurs additional in-rack communications that can be further minimized. Based on this, we propose a flexible scheduler that improves communication efficiency while preventing deadlocks and congestion caused by the flexibility. Through a comprehensive evaluation, we show that our approach reduces the overall latency by a factor of 8.02, thereby mitigating qubit decoherence, with a small overhead.
@article{arxiv.2412.04837,
title = {Optimizing Quantum Communication for Quantum Data Centers with Reconfigurable Networks},
author = {Hezi Zhang and Yiran Xu and Haotian Hu and Keyi Yin and Hassan Shapourian and Jiapeng Zhao and Ramana Rao Kompella and Reza Nejabati and Yufei Ding},
journal= {arXiv preprint arXiv:2412.04837},
year = {2024}
}