Complete Phase Diagram of DNA Unzipping: Eye, Y-fork and triple point
  We study the unzipping of double stranded DNA (dsDNA) by applying a pulling force at a fraction $s$ $(0 \le s \le 1)$ from the anchored end. From exact analytical and numerical results, the complete phase diagram is presented. The phase diagram shows a strong ensemble dependence for various values of $s$. In addition, we show the existence of an ``eye'' phase and a triple point. 
Rajeev Kapri, Somendra M. Bhattacharjee and Flavio Seno