Abstract: | We discuss the dynamics of binary fluid mixtures in which surface tension density is allowed to become locally negative within
the interface, while still preserving positivity of the overall surface tension (heterogeneous diffuse interface). Numerical
simulations of two-dimensional Ginzburg-Landau phase field equations implementing such mechanism and including hydrodynamic
motion, show evidence of dynamically arrested domain coarsening. Under specific conditions on the functional form of the surface
tension density, dynamical arrest can be interpreted in terms of the collective dynamics of metastable, non-linear excitations
of the density field, named compactons, as they are localized to finite-size regions of configuration space and strictly zero
elsewhere. Aside from compactons, the heterogeneous diffuse interface scenario appears to provide a robust mechanism for the
interpretation of many aspects of soft-glassy behaviour in binary fluid mixtures. |