A tracker solution to the cold dark matter cosmic coincidence problem

Recently, we introduced the notion of ''tracker fields,'' a form of quintes sence which has an attractor-like solution. Using this concept, we showed h ow to construct models in which the ratio of quintessence to matter densiti es today is independent of initial conditions. Here we apply the same idea to the standard cold dark matter component in cases where it is composed of oscillating fields. Combining these ideas, we can construct a model in whi ch quintessence, cold dark matter, and ordinary matter all contribute compa rable amounts to the total energy density today irrespective of initial con ditions. (C) 1999 Published by Elsevier Science B.V. All rights reserved.