Universal photonic quantum computation via time-delayed feedback
Hannes Pichler, Soonwon Choi, P. Zoller, Mikhail D. Lukin · Proceedings of the National Academy of Sciences · 2017
Significance Creating large entangled states with photons as quantum information carriers is a central challenge for quantum information processing. Since photons do not interact directly, entangling them requires a nonlinear element. One approach is to sequentially generate photons using a quantum emitter that can induce quantum correlations between photons. Here we show that delayed quantum feedback dramatically expands the class of achievable photonic quantum states. In particular, we show that in state-of-the-art experiments with single atom-like quantum emitters, the most basic form of delayed quantum feedback already allows for creation of states that are universal resources for quantum computation. This opens avenues for quantum information processing with photons using minimal experimental resources.