Entanglement in Mesoscopic Structures: Role of Projection

A. V. Lebedev, G. Blatter, C. W. J. Beenakker, G. B. Lesovik

Published 2003-11-28, updated 2003-12-07Version 3

We present a theoretical analysis of the appearance of entanglement in non-interacting mesoscopic structures. Our setup involves two oppositely polarized sources injecting electrons of opposite spin into the two incoming leads. The mixing of these polarized streams in an ideal four-channel beam splitter produces two outgoing streams with particular tunable correlations. A Bell inequality test involving cross-correlated spin-currents in opposite leads signals the presence of spin-entanglement between particles propagating in different leads. We identify the role of fermionic statistics and projective measurement in the generation of these spin-entangled electrons.