Swapping path-spin intraparticle entanglement onto spin-spin interparticle entanglement

Abstract

Based on a scheme that produces an entanglement between the spin and the path variables of a single spin-(1/2) particle (qubit) using a beam-splitter and a spin-flipper, we formulate a procedure for transferring this intraparticle hybrid entanglement to an interparticle entanglement between the spin variables of two other spatially separated spin-(1/2) particles which never interact with each other during the entire process. This procedure of entanglement swapping is accomplished by a Mach-Zehnder setup in conjunction with the Stem-Gerlach measuring device and by using suitable unitary operations. The proposed protocol, thus, enables the use of intraparticle entanglement as a resource-a feature that has remained unexplored.