Robust and scalable scheme to generate large-scale entanglement webs
Keisuke Fujii, Haruki Maeda, Katsuji Yamamoto · Physical Review A · 2011
We propose a robust and scalable scheme to generate an $N$-qubit $W$ state among separated quantum nodes (cavity-QED systems) by using linear optics and postselections. The present scheme inherits the robustness of the Barrett-Kok scheme [S. D. Barrett and P. Kok, Phys. Rev. A 71, 060310(R) (2005)]. The scalability is also ensured in the sense that an arbitrarily large $N$-qubit $W$ state can be generated with a quasipolynomial overhead $~$${2}^{O[(\mathrm{log}{}_{2}N){}^{2}]}$. The process to breed the $W$ states, which we introduce to achieve the scalability, is quite simple and efficient and can be applied for other physical systems.