Rare earth quantum memories for applications in quantum communication

Rare-earth ions embedded in crystals carry great prospect in developing quantum memories due to their good coherence properties for both optical and hyperfine transitions and their engineering feasibility as solid. In recent years, various quantum storage protocols have been exploited based on these systems and remarkable achievement in memory performance have been realized. In this talk, I will first briefly review the status quo in the experimental research on rare-earth-based quantum memories and analyze the current technological challenges. Then I will talk about our work on the preservation of quantum coherence over a few hours. This result opens the possibility to realize entanglement distribution over a global scale by physically transporting the memory crystals. Finally, I would also talk about our work on improving the storage efficiency and on exploring new materials and applications