Depletion forces in hard-sphere colloids

A system of monosized hard spheres is studied to elucidate the nature of en tropic depletion forces. Our calculations include effective forces between two spheres, a hard sphere and a wall, and the behavior near a step edge an d a corner. Qualitative differences between our results and those of the As akura-Oosawa theory are found. We also demonstrate the nonadditivity of suc h entropic forces in a simple example.