Linear optical Fredkin gate based on partial-SWAP gate

Abstract

We propose a scheme for linear optical quantum Fredkin gate based on the combination of recently experimentally demonstrated linear optical partial-SWAP gate and controlled-Z gates. Both heralded gate and simplified post-selected gate operating in the coincidence basis are designed. The suggested setups have a simple structure and require stabilization of only a single Mach-Zehnder interferometer. A proof-of-principle experimental demonstration of the post-selected Fredkin gate appears to be feasible and within the reach of current technology.