Mar 11 2008
The March Meeting of American Physical Society is taking place from March 10-14, 2008 in New Orleans, Louisiana. More than 7,000 scientists are expected to be on hand. The principal topic areas will be condensed matter physics, industrial applications, new materials, chemical and biological physics, fluids, polymers, and computation.
The March meeting is both a great showcase for fundamental physics research and an engine for producing the kind of practical devices and phenomena that characterize our technological society.
Below are some selected talks that will be presented at the meeting. For further information visit the APS March Meeting program site at http://www.aps.org/meetings/march/index.cfm
OPTICAL LATTICES FOR QUANTUM COMPUTING
Quantum computing just got one stop closer with an advance in optical lattice technology. David Weiss (Penn State) will describe a 3D optical lattice partially filled with individual atoms at 250 sites. Ultimately, Weiss and his colleagues hope to use the atoms as qubits in a quantum computer. Unlike previous 3D lattices, the spacing between the atoms in the new system is large enough that the atoms can be individually manipulated with lasers and microwaves without disturbing neighboring atoms. The atoms' individual addressability and the fact that the atoms have multiple neighbors to quantum mechanically interact with make the system a promising route to quantum computing. (paper B6.4)
MATERIAL PHYSICS GETS OUT OF THE LAB
What do race cars, motorcycles, superheroes and steroids have in common" They're all topics addressed in session D3: Materials Physics in the Fast Lane. Charles Falco of the University of Arizona will start off the session with a look at the high-tech materials that help modern motorcycles achieve power-to-weight ratios a hundred times those of bikes built a century ago. Diandra Leslie-Pelecky (University of Nebraska), author of the forthcoming book "The Physics of NASCAR," follows, describing the science behind the cars, safety gear and tracks that are vital to stock car racing, the nation's most popular spectator sport. Roger Tobin of Tufts takes on a much more controversial subject as he analyzes the effects of illegal performance-enhancing drugs on homerun rates in baseball. NASA's John Wood describes the significance of the advanced optical glass that has made the Hubble Space Telescope one of the most important scientific tools in history. And finally, the author of "The Physics of Superheroes," James Kakalios (University of Minnesota), will talk about modern marvels that were once only the domain of comic book superheroes, including shape-memory materials, artificial retinas, and adhesive surfaces modeled on gecko feet.
TIN BUCKYBALLS ARE BETTER THAN GOLD
Buckyballs (fullerenes) are tiny spherical clusters of atoms. The first ones ever found were carbon buckyballs, then came gold, but the best buckyballs of all might be the recently discovered tin variety. Fullerenes are important in part because their properties can be adjusted by trapping other atoms at the center of the atomic cages. But some important elements interact strongly with gold and can't be trapped inside golden fullerenes, which limits the structure's potential for chemical applications. Lai-Sheng Wang (Washington State University and Pacific Northwest National Laboratory) points out that tin fullerenes, on the other hand, can accommodate a number of important transition metal atoms and may end up being the most chemically versatile form of fullerenes discovered so far. (paper B21.5)
NANOPARTICLES KILL TUMORS IN RATS
The ability to deliver drugs specifically to one part of the brain or some other specific tissue in the body is highly desirable in diseases like cancer, where the drugs may have widespread toxicity to healthy cells throughout the body. One nanotechnology-based approach to solving this problem was designed about 10 years ago by Raoul Kopelman (University of Michigan). Kopelman found a way of making tiny polyacrylamide particles about 60 nanometers in diameter that can be imbedded with drugs or other compounds and safely delivered to the bloodstream. Moreover, antibodies or other "targeting" molecules can be attached to the outside of the particles so that they can ferry this payload though the body and dock at the tissues where the drugs are needed. In his talk, Kopelman describes one experiment where he and his colleagues decorated these particles with peptides that helped guide them into the nuclei of cancer cells in the brain, There, MRI contrast agents loaded in these nanoparticles helped image the tumor cells, and when illuminated by a laser, photodynamic chemicals inside the nanoparticles released highly-reactive singlet oxygen into the cancer cells, killing them. One 5-minute blast with simple red laser cured a few rats of glioblastoma, one particularly nasty form of brain cancer.
MICRO-OCEAN
An important part of the biosphere is the population of organisms, especially micro-organisms, which stand at the lowest level of the food chain but which dominates all others in terms of mass. At his MIT lab, Roman Stocker looks at such micro societies in ecological landscapes created on micro-fluidic chips. To marine bacteria, the ocean is a desert, a place where nutrients are scarce. Stocker will report on surprising signs that bacteria are much more efficient than was previously thought in their search for patches of nutrients. This might be an important step in studying how carbon and carbon dioxide are taken up in the ocean. (paper P6.4)
SWITCH ALTERNATIVES FOR MICROELECTRONICS
Miniaturization is the primary focus of most efforts to advance the state of the art in microelectronics. An added benefit of shrinking devices is that energy efficiency tends to improve dramatically as well, with one notable exception - even at tiny dimensions transistors are power-hungry components. Session S2 focuses on the increasing importance of finding alternatives to transistors in microelectronics. Eli Yablonovitch (University of California, Berkeley) will start the session off by considering a number of low voltage alternatives to transistors. Among the other speakers in the invited session, Joerg Appenzeller (Purdue) will consider solid state carbon nanotube devices, and Marc Baldo (MIT) will describe a prototype nanoscopic mechanical switch (also built of carbon nanotubes) that has the potential to eliminate losses characteristic of transistors, operate at low voltages, and run at much higher temperatures than typical of many silicon-based devices.
SOLAR CELLS: THE NEXT GENERATION
More silicon goes into the making of solar cells than into the making of microchips. Although accounting for only a tiny portion of overall electricity generation so far, solar cells are moving up quickly. For the past five years the amount of solar-generated electricity has increased by about 40% per year. Mass production of solar panels will help immensely in the overall long-term goal of bringing the cost of solar electricity down closer to that of coal-fired electricity. In the meantime, the things physicists can do are to explore new ways to make the cells more efficient and cheaper to produce. Session L2 is devoted to this effort. For example, one paper will consider the use of silicon nanocrystallites rather than more cumbersome (and expensive) single-crystal configurations used in present cells. Making cells from dye-sensitized paint components (titanium dioxide particles) is another route to cost reduction.