Yang-Mills instanton as a quantum black hole
  In terms of spin-charge separated variables, the Minkowski space Yang-Mills BPST instanton describes a locally conformally flat doubly-wrapped cigar manifold that can be viewed as a Euclidean quantum black hole. An ensemble of instantons then corresponds to a ``spacetime foam'' that creates a locally conformally flat spacetime from ``nothing'' as a quantum fluctuation. 
Sergey Slizovskiy