Past Events

Abstract
 

To build an unhackable communication network, one requires the transmission of quantum signals over long distances. Much like classical communications, the transmission of such signals is fundamentally limited by noises present in the channel. Quantum repeater is a device that creates a quantum entanglement between two distant locations in the presence of channel noises, which aims to transfer information with high rates. Such device is therefore indispensable to the realization of a quantum communication network.

This talk concerns the feasibility of a repeater model called the “all-photonic quantum repeater”, by addressing one of its major challenges---the difficulty in the generation of repeater graph states (RGS) used in the repeater. The RGSs created by today’s protocols are not encoded, which makes them highly vulnerable to fiber attenuation. In addition, a systematic estimation of the overhead and performance of these RGS generation protocols is currently missing. To address these two research gaps, I presented a protocol to create an encoded RGS, by considering symmetry features that are omitted in previous protocols. Together with the use of a deterministic spin-photon interface, the protocol is expected to outperform existing protocols by having a comparatively lower resource requirement, and an all-round improvement in secret key rates of the repeater.