On the possibility of the generation of an artificial wormhole
  We model spacetime foam by a gas of virtual wormholes. Then applying an external field one may change the density of virtual wormholes and try to organize a wormhole-like structure in space. The relation between an additional distribution of virtual wormholes and the external field is considered for the homogeneous case. We show that the external fields suppress the density of virtual wormholes which sets an obstruction for creating an actual wormhole in a straightforward fashion. We also present a rough idea of a more complicated model for the artificial creation of a wormhole. 
E.P. Savelova, A.A. Kirillov
gr-qc hep-th