String Theory and The Arrow of Time
  Time-like linear dilaton triggers, at the classical level, the creation of
closed folded strings at an instant. We show that in cosmology these instant
folded strings induce negative pressure at no energy cost. Hence they seem to
allow an era in which the energy density increases (decreases) while the
universe is expanding (contracting). This and other aspects of instant folded
strings suggest that they might shed new light on the origin of the arrow of
time.
