Postselection induced entanglement swapping from a vacuum--excitation   entangled state to separate quantum systems
  We show that a single particle in a superposition of different paths can entangle two objects located on each path. The entanglement has its maximum visibility for intermediate coupling strengths. In particular, when the two quantum systems with which the particle interacts are detectors that measure its presence and its polarization, the so-called quantum Cheshire cat is realized. 
Antonio Di Lorenzo
quant-ph cond-mat.mes-hall physics.optics