Number 66, February 3, 1992 by Phillip F. Schewe and Ben Stein|
QUANTUM CHAOS , where quantum behavior and chaotic behavior overlap, has been demonstrated in experiments involving electrons scattering from small molecules. During the scattering process, an electron travels between the atoms in the molecule as if it were moving through a maze, with numerous possible trajectories that depend sensitively on the electron's starting momentum. The average time for an electron of fixed momentum to escape the maze of atoms was found to vary chaotically with its momentum. Martin C. Gutzwiller of IBM has shown that the variation in the arrival time may be described quantum-mechanically through the mathematical zeta function. This function is used widely in mathematics to describe prime numbers and may someday provide a general description of chaotic behavior in quantum mechanics. (Scientific American, Jan. 1992.)
INTELLIGENT MATERIALS are to physical structures (bridges, airplanes, buildings, machines, etc.) what the immune system and the nervous system are to the human body: they serve as embedded sensors of temperature, strain, corrosion, electric current, and a host of other chemical and physical indicators. Piezoelectric ceramics, for example, can turn electrical signals into mechanical strain, or vice versa. This ability might sense fatigue in a bridge support or an airplane wing, and give warning. Electro-rheological fluids transform from a liquid to a solid when heated, and back again when cooled. Shape-memory alloys can be easily moulded at lower temperatures, but return to an orignal shape when heated above a critical temperature. Intelligent materials now have their own journals, scientific meetings, and specialized institutions at places like the Univeristy of Strathclyde (Scotland), Virginia Polytechnic, Michigan State, and Toronto. (Science, 17 Jan. 1992.)
PHYSICS AND GOVERNMENT need each other more than ever. Government counts on physics and the other sciences for help in competing in the global technological marketplace. And physics, if it is to create miracle materials and explore nature at the coldest temperatures and highest energies, needs government funding for procuring state-of-the-art equipment. To help monitor this interdependence, the AIP Office of Government and Institutional Relations in Washington issues short, weekly reports, called FYI, on a variety of subjects such as pending science legislation, committee hearings, and trends in research funding. FYI can be obtained gratis (whether you are a reporter or a scientist) by contacting Richard M. Jones at 202-234-7058 or by electronic mail at email@example.com. Also not to be missed is the incomparable "What's New," the weekly online wrapup of physics and government news from the nation's capital, produced by Robert L. Park, director of the American Physical Society's Office of Public Affairs (202-232-0189).