  We report the propagation of highly nonlinear solitary waves in
heterogeneous, periodic granular media using experiments, numerical
simulations, and theoretical analysis. We examine periodic arrangements of
particles in experiments in which stiffer/heavier beads (stainless steel) are
alternated with softer/lighter ones (PTFE beads). We find excellent agreement
between experiments and numerics in a model with Hertzian interactions between
adjacent beads, which in turn agrees very well with a theoretical analysis of
the model in the long-wavelength regime that we derive for heterogeneous
environments and general bead interactions. Our analysis encompasses
previously-studied examples as special cases and also provides key insights on
the influence of the dimer lattice on the properties (width and propagation
speed) of the obtained highly nonlinear wave solutions.
