Macroscopic Entanglement by Entanglement Swapping
  We present a scheme for entangling two micromechanical oscillators. The scheme exploits the quantum effects of radiation pressure and it is based on a novel application of entanglement swapping, where standard optical measurements are used to generate purely mechanical entanglement. The scheme is presented by first solving the general problem of entanglement swapping between arbitrary bipartite Gaussian states, for which simple input-output formulas are provided. 
Stefano Pirandola, David Vitali, Paolo Tombesi, and Seth Lloyd