Linear optical Fredkin gate based on partial-SWAP gate

TL;DR

This paper proposes a linear optical Fredkin gate using partial-SWAP and controlled-Z gates, featuring simple setup and feasible experimental demonstration with current technology.

Contribution

It introduces a novel scheme combining partial-SWAP and controlled-Z gates for a linear optical Fredkin gate with simplified setup.

Findings

Design of heralded and postselected Fredkin gates

Feasibility of experimental demonstration with current technology

Simplified setup requiring stabilization of only one interferometer

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 postselected 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 postselected Fredkin gate appears to be feasible and within the reach of current technology.