Holography and String Dynamics in Time-dependent Backgrounds
  We study the dynamics of D-branes in a smooth time-dependent background. The theory on the branes is a time-dependent non-commutative field theory. We find the metric and fluxes that determine the dual holographic closed string theory. This provides a concrete example of holography in a cosmological setting. 
Akikazu Hashimoto and Savdeep Sethi