The quantum network is one of the ultimate goals of emerging quantum technologies. It enables sharing of entangled qubits over a far distance. The most prominent application being developed at the moment is quantum key distribution (QKD), where the quantum property of the information carrier allows for the exchange of provably secure key distribution. However, its usable distance is limited to only a few hundred kilometers due to an inevitable trade-off between distance and key rate.

Fortunately, the quantum repeater is known to be a great platform to overcome this challenge by extending the distance between nodes. Over the past decade, nitrogen-vacancy (NV) centers in diamonds have shown outstanding performance as quantum repeaters. However, when combined with nano-devices, their unstable nature presents an overwhelming challenge for practical deployment in real-life applications. As an alternative, the silicon-vacancy (SiV) color center is emerging as a potential solution. Thanks to its outstanding stability within nano-devices, it allows for near-deterministic single photon-spin interactions that pave the way to practical quantum repeaters.

In this seminar, I will discuss the technical problems related to quantum repeater engineering by comparing two outstanding platforms for quantum repeaters.