High-speed linear optics quantum computing using active feed-forward

Until now experimental proof-of-principle demonstrations of optical quantum computers have been probabilistic: that is, the computation succeeds in only a small fraction of runs. Exploiting a computer architecture called one-way quantum computation, Prevedel et al. have now succeeded in undoing emergent errors by 'feed-forwarding' those events and applying error correction in real time. In effect the quantum computer is forced to produce the right result when the 'compute' button is pressed. This experimental demonstration of one-way quantum computation could be a key result for the future development of these systems.