Flow of the Coarse Grained Free Energy for Crossover Phenomena
  The critical behaviour of a system of two coupled scalar fields in three dimensions is studied within the formalism of the effective average action. The fixed points of the system are identified and the crossover between them is described in detail. Besides the universal critical behaviour, the flow of the coarse grained free energy also describes the approach to scaling. 
S. Bornholdt, P. Buettner, N. Tetradis, C. Wetterich