Feed-forward and its role in conditional linear optical quantum dynamics

Abstract

Nonlinear optical quantum gates can be created probabilistically using only single photon sources, linear optical elements and photon-number resolving detectors. These gates are heralded but operate with probabilities much less than one. There is currently a large gap between the performance of the known circuits and the established upper bounds on their success probabilities. One possibility for increasing the probability of success of such gates is feed-forward, where one attempts to correct certain failure events that occurred in the gate's operation. In this brief report we examine the role of feed-forward in improving the success probability. In particular, for the non-linear sign shift gate, we find that in a three-mode implementation with a single round of feed-forward the optimal average probability of success is approximately given by p= 0.272. This value is only slightly larger than the general optimal success probability without feed-forward, P= 0.25.

4 pages, 3 eps figures, typeset using RevTex4, problems with figures resolved

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Cited by in corpus (8)

• Review article: Linear optical quantum computing
• Recent development of complex scaling method for many-body resonances and continua in light nuclei
• Potential and limits to cluster state quantum computing using probabilistic gates
• Minimal resources for linear optical one-way computing
• Generation of picosecond pulsed coherent state superpositions
• Quantum repeater protocol using an arrangement of QED-optomechanical hybrid systems
• Integration of highly probabilistic sources into optical quantum architectures: perpetual quantum computation
• Concatenated beam splitters, optical feed-forward and the nonlinear sign gate