Formation of Cosmic String network from black holes: Implications from   liquid crystal experiments
  We present observation of large, expanding string loops forming around a heated wire tip embedded in a nematic liquid crystal sample. Loops expand due to convective stretching. This observation leads to a new insight into phenomena which could occur in the early universe. We show that local heating of plasma in the early universe by evaporating primordial black holes can lead to formation of large, expanding cosmic string loops, just as observed in the liquid crystal experiment. Intercommutation of string loops from neighboring black holes can lead to percolation, thereby forming an infinite string network. This is remarkable as such an infinite string network is thought to arise only when the entire universe undergoes phase transition. 
Ajit M. Srivastava