String Junction Transitions in the Moduli Space of N=2 SYM
  The string theory description of BPS states in D-brane world-volume field theories may undergo transitions from open strings to string webs, as well as between different string webs, as one moves in the field theory moduli space. These transitions are driven by the string creation phenomenon. We demonstrate such transitions in the D3-brane realization of N=2 SU(2) Super-Yang-Mills theory. 
O. Bergman (Harvard), A. Fayyazuddin (Harvard)