A poster session featuring work by 20 groups followed the morning's speaker session. The first speaker was Katja Lindenberg, UCSD professor of chemistry and associate director of the Institute for Nonlinear Studies. Lindenberg reviewed the statistical properties of noise. Although noise is defined as something undesirable, there are systems in which it is absolutely necessary. Such systems exhibit stochastic resonance or may be subject to noise-induced currents.
Examples occur in DNA denaturation and in diffusion-limited chemical reactions.
The second speaker was Frances Hellman, a professor in the UCSD Physics Department. In her talk, Hellman noted that amorphousness may not be quite random, and crystalline may not be perfectly ordered. Hellman described a regime of vapor deposition growth which is proving important in the development of thin films for magneto-optic recording processes. In this regime, it is possible to balance the depositional forces to control the texture of the growing film surface in such a way that the direction of magnetization can lie out of the plane of the film. To achieve this kind of control, it is necessary to recognize, first, that chemical vapor deposition cannot be automatically assumed to be producing a small sample identical to the original bulk material and, second, to distinguish the various geometries of order.