  The equation of motion for a point particle in the background field of double
field theory is considered. We find that the motion is described by a geodesic
flow in the doubled geometry. Inspired by analysis on the particle motion, we
propose a modified model of quantum string cosmology, which includes two scale
factors. The report is based on Phys. Rev. D84 (2011) 124049 [arXiv:1108.5795].
