Emergent phenomena share the fascinating property of not being obvious
consequences of the design of the system in which they appear. This
characteristic is no less relevant when attempting to simulate such phenomena,
given that the outcome is not always a foregone conclusion. The present survey
focuses on several simple model systems that exhibit surprisingly rich emergent
behavior, all studied by MD simulation. The examples are taken from the
disparate fields of fluid dynamics, granular matter and supramolecular
self-assembly. In studies of fluids modeled at the detailed microscopic level
using discrete particles, the simulations demonstrate that complex hydrodynamic
phenomena in rotating and convecting fluids, the Taylor-Couette and
Rayleigh-B\'enard instabilities, can not only be observed within the limited
length and time scales accessible to MD, but even quantitative agreement can be
achieved. Simulation of highly counterintuitive segregation phenomena in
granular mixtures, again using MD methods, but now augmented by forces
producing damping and friction, leads to results that resemble experimentally
observed axial and radial segregation in the case of a rotating cylinder, and
to a novel form of horizontal segregation in a vertically vibrated layer.
Finally, when modeling self-assembly processes analogous to the formation of
the polyhedral shells that package spherical viruses, simulation of suitably
shaped particles reveals the ability to produce complete, error-free assembly,
and leads to the important general observation that reversible growth steps
contribute to the high yield. While there are limitations to the MD approach,
both computational and conceptual, the results offer a tantalizing hint of the
kinds of phenomena that can be explored, and what might be discovered when
sufficient resources are brought to bear on a problem.Comment: 21 pages, 20 figures (v2 - minor text addition