ENTROPY FUNCTIONAL FOR LAYERED ISING-MODELS - WEAK-COUPLING LIMIT

The perturbative expansion of a spatially nonuniform phi4-field theory is rearranged leading to an entropy functional of the magnetization a nd energy densities. Similarly to the planar Ising model considered ea rlier, a form local in the two leading orders is achieved in the case of parameters of the theory depending on only one of the d spatial coo rdinates. The functional then depends on all transverse Fourier compon ents of the energy density. The result forms a basis for future work o n the perturbative renormalization-group approach to nonuniform Ising- like systems.