Deterministic generation of photonic tree and repeater graph states with a single quantum emitter

Photon loss is the dominant error in optical quantum computing and quantum networking. An efficient way to deal with loss fault-tolerantly is to employ a photonic cluster state with a tree-type entanglement structure to encode a single logic qubit. However, due to the lack of means to induce photon-photon interactions, the generation of a tree cluster state with an arbitrary size is notoriously difficult. Here, we propose a protocol to deterministically generate photonic tree states of arbitrary size by using only a single quantum emitter [1]. Photonic entanglement is established through both emission and re-scattering from the same emitter, enabling fast and resource-efficient entanglement generation. The same protocol can also be extended to generate more general tree-type entangled states, such as repeater graph states. Our results pave the way towards the realization of loss-tolerant one-way optical quantum computers and all-optical quantum repeaters.
[1] Y. Zhan and S. Sun, arXiv:2007.06608.