Noncommutative cosmological models coupled to a perfect fluid and a   cosmological constant
  In this work we carry out a noncommutative analysis of several Friedmann-Robert-Walker models, coupled to different types of perfect fluids and in the presence of a cosmological constant. The classical field equations are modified, by the introduction of a shift operator, in order to introduce noncommutativity in these models. We notice that the noncommutative versions of these models show several relevant differences with respect to the correspondent commutative ones. 
E. M. C. Abreu, M. V. Marcial, A. C. R. Mendes, W. Oliveira and G.   Oliveira-Neto
hep-th gr-qc math-ph math.MP