Rolling Tachyons in String Cosmology
  We study the role of rolling tachyons in the cosmological model with dilatonic gravity. In the string frame, flat space solutions of both initial-stage and late-time are obtained in closed form. In the Einstein frame, we show that every expanding solution is decelerating. 
Chanju Kim (Ewha W.U.), Hang Bae Kim (Lausanne U.), Yoonbai Kim   (Sungkyunkwan U.)