Multiple reentrance and fractal phase boundaries in the Barker-Fock model

The Barker-Fock model, which addresses the issue of closed-loop phase diagr ams in binary liquid mixtures, is shown to exhibit a wealth of interesting and rather unexpected physical phenomena. For example, renormalization-grou p studies indicate that in addition to the standard closed-loop diagrams se en in many binary liquid mixtures, the Barker-Fock model also yields multip le reentrance - perhaps of unlimited degree. In addition, one of the "phase boundaries" in the model is actually many separate phases mixed together t o form a "fractal foam". Behavior of this kind is interesting in its own ri ght, and particularly so when the underlying model has direct physical rele vance. (C) 2000 Elsevier Science B.V. All rights reserved.