title: Topological quantum computing with a very noisy network and local error rates approaching one percent.
abstract: A scalable quantum computer could be built by networking together many simple processor cells, thus avoiding the need to create a single complex structure. The difficulty is that realistic quantum links are very error prone. A solution is for cells to repeatedly communicate with each other and so purify any imperfections; however prior studies suggest that the cells themselves must then have prohibitively low internal error rates. Here we describe a method by which even error-prone cells can perform purification: groups of cells generate shared resource states, which then enable stabilization of topologically encoded data. Given a realistically noisy network (≥10% error rate) we find that our protocol can succeed provided that intra-cell error rates for initialisation, state manipulation and measurement are below 0.82%. This level of fidelity is already achievable in several laboratory systems.
authors.affiliation: Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK.
authors.forename: Naomi H
authors.initials: NH
authors.lastname: Nickerson
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Simon C
authors.initials: SC
authors.lastname: Benjamin