Deterministic photon-photon (SWAP)^{1/2} gate using a lambda system

摘要

We theoretically present a method to realize a deterministic photon-photon(SWAP)^{1/2} gate using a three-level lambda system interacting with singlephotons in reflection geometry. The lambda system is used completely passivelyas a temporary memory for a photonic qubit; the initial state of the lambdasystem may be arbitrary, and active control by auxiliary fields is unnecessarythroughout the gate operations. These distinct merits make this entangling gatesuitable for deterministic and scalable quantum computation.