American Physical Society March Meeting 2003

The biggest physics meeting of the year

College Park, MD, January 23, 2003: The biggest physics meeting of the year, the American Physical Society (APS) March Meeting, will be held March 3-7, 2003 in Austin, Texas. An estimated record 5600 talks will be delivered. The APS March Meeting is traditionally a showcase for both important fundamental physics and also the kind of applied physics that forms the backbone of modern technology in all its diverse forms: computing, displays, lighting, photon-based and wireless communications, global positioning, smart materials, medical imaging, automated study of biological molecules, sensing and scanning, printing, the mixing of powders and fluids, and early cancer detection.

Further down in this press release you will see a more detailed list of possible highlight sessions at the meeting. But here are some quick examples of the immense diversity of topics to be exhibited during the week. In the area of solid state lighting, LED's with high efficiencies and high power will lead to LED backlighting and auto headlights (session V7). Magnetic resonance force microscopy (MRFM), the marriage of STM and MRI technology, seeks to produce atomic-scale images of biomolecules (session P14). The smallest doped fullerenes, cage molecules consisting of less than 30 carbon atoms, have been turned into solids (paper A25.1).

Other topics: cultivating physics and physicists in Africa (H2); radiation processing in food packaging, mail handling, and bio-electrodes (B8); global infrasound monitoring in the atmosphere for studying volcanoes and weather (paper H3.2); assessing the value of physics research to the economy (session S2); superfluid gyroscopes (G4.2); single-molecule LEDs (P11.3); quantum cellular automata (P19.4); cerebral synchronization (N15.12); are sunscreens bad for you? (X31.3)

SOME EXPECTED HIGHLIGHTS OF THE MEETING

NEW DISCOVERIES IN THE RNA WORLD
Which molecule is responsible for the origin of life? An increasingly popular candidate is RNA. Like DNA, RNA is made from four molecular "bases" (A, C, G, and U) that can carry genetic instructions. Like proteins, RNA can fold into enzyme-like molecules that catalyze important biochemical activities. Last month, the journal Science named discoveries on such molecules as the #1 breakthrough of 2002. At session G10, researchers will present intriguing findings on the folding properties of RNA. Ranjan Mukhopadhyay ([email protected]) and his colleagues at NEC Laboratories in New Jersey have found that a typical RNA sequence with its 4-letter code folds more predictably and stably than would hypothetical RNA sequences based on 2- and 6-letter alphabets. If early life was indeed RNA-based, Mukhopadhyay says, nature may have chosen a 4-letter genetic code because of RNA's folding properties. Ralf Bundschuh of Ohio State ([email protected]) and Terence Hwa of UC-San Diego have found that RNA, under certain conditions, can become "glassy," meaning that a given RNA sequence can fold into random, rather than pre-determined, structures. The study of such phase behavior in RNA can elucidate similar but harder-to-test questions in protein folding. Exploring how different organisms produce the same RNA structures from different sequences, Erik Schultes of the Whitehead Institute of MIT ([email protected]) will discuss experimental evidence of "neutral networks," harmless changes in RNA sequence that still produce the same folds in an RNA molecule. But occasionally, neutral networks might "intersect," meaning that one sequence can fold in two different ways, supporting a mechanism whereby different RNA structures could have evolved from the same ancestral sequence.

PROCESSING INFORMATION WITH ULTRA-SLOW LIGHT
Following on from slowing and stopping light in ultra-cold gas clouds, Zachary Dutton (National Institute of Standards and Technology) and Lene Hau (Harvard University) will show how a Bose-Einstein condensate (BEC) can store and process optical information (K34.4). This may be the first step toward quantum computation in BECs. Various other researchers will present the latest results on trapping arrays of BECs for use in quantum information processing. (Session H4)

MAGNETIC REFRIGERATORS
Magnetic refrigerators, in which the switching on and off of a strong magnetic field drives the refrigeration process, have in the past been hampered by the need for extremely large magnetic fields and often didn't work at room temperatures. Four groups will report on new magnetic refrigerators that operate with one tenth of previous field strength at usable temperatures. One group reports a 12 degree Celsius (22 degrees Fahrenheit) cooling effect and achieving temperatures below freezing. (Session K7)

FIRST 3D X-RAY IMAGING SYSTEM FOR BREAST CANCER
In work that may greatly improve the detection of breast cancer, GE researchers, in collaboration with Massachusetts General Hospital and the Uniformed Services University of the Health Sciences in Maryland, will report on the first x-ray system that images the breast in 3D. Called "full-field digital mammography tomosynthesis," the system fires 10-20 low-dose x-rays from various angles to a stationary patient and detector. In its current implementation, the system exposes a patient to just three-fourths of the x-ray dose of conventional 2D mammograms (which require 2 full x-ray exposures, in contrast to the single multi-angle sweep in the new technique). In preliminary clinical trials, tomosynthesis could determine malignancy in breast lesions better than conventional 2D digital mammography. That's because benign structures (such as fibroglandular tissue) can lay in front of suspicious lesions and block the view in 2D pictures. In tomosynthesis ("tomo" is Greek for section or slice and "synthesis" is the act of putting together), physicians can get a view of the breast from various angles and at multiple depths. In addition, tomosynthesis requires less breast compression than traditional mammography, resulting in a more comfortable exam. (Jeffrey Eberhard, GE, [email protected], P10.1)

COMICS, BASEBALL, AND HOLLYWOOD
Physics principles can be used for fun and profit in elucidating many aspects of everyday life. Conversely, some of the more glamorous parts of mass culture can be used to help teach physics. This notion will be explored in session 3A (Thursday, March 7, 7 PM). The three speakers will be James Kakalios (Univ Minnesota) who teaches a course in the "science of comic books," Robert Adair (Yale) who has written a book on the physics of baseball, and Lawrence Krauss (Case Western Reserve) who will talk about physics in movies and on TV.

READING BETWEEN THE LINES
As we currently understand it, as much as 97% of human DNA is believed to be junk. That is, only a very tiny fraction of the human genome contains instructions for sequence of building blocks that comprise the proteins that make up our body structures, and the rest appears to be filler. Nevertheless it is important to study junk DNA to understand why we seem to have so much of it, whether it has a purpose, and what that purpose might be. It is also vital to distinguish it from the portions of the genome that contain protein coding DNA. In paper N10.1, Gene Stanley of Boston University will discuss new methods for analyzing both coding and noncoding (junk) DNA in parallel, with a view to uncovering the statistical properties of the two kinds of DNA. He will also present arguments for the possible roles of noncoding DNA in the genome. Background and details regarding these arguments are available on the website http://polymer.bu.edu/hes.

SOLAR CELLS
The production of electricity with solar cells has of late been increasing at a rate of 40% per year, higher even than for wind-powered technology. The key to sustaining this growth is through increasing the efficiency of the cells (the ratio of usable electricity to sunlight) and using cheaper and more manageable materials. The first generation cells used silicon wafers and commercial module efficiency values were about 10-15%. The second generation cells used thin film modules and efficiencies were about 5-9%. Last year the first of the third-generation devices appeared, those depending on abundant, non-toxic materials. Session A8 features the latest the on photovoltaic research. For instance, Allan Barnett (AstroPower, Inc.), CEO of the largest company dealing exclusively with photovoltaic research, will provide an introduction to the subject. Stephanie Chasteen (UC Santa Cruz) will describe how plastic solar cells lead can be integrated into clothing and mobile phones. Martin Green (University of New South Wales) will report on new second-generation devices and on the process by which third-generation materials will be winnowed ([email protected]; website http://www.pv.unsw.edu.au/)

RISK ANALYTICS
Evan Picoult earned a PhD in particle physics but, like many a scientist, his interests and the job market took him in a different direction. He became interested in neurobiology and psychology, then got an MBA and went into finance theory. He now works at Citicorp in the field of risk analytics, the study of the value and risk associated with financial contracts. More than an art but less than a science, risk analytics bears some resemblance to physics, relying as it does on equations and modeled from statistics and probability theory, but one must always keep in mind that the human element in finance can trump invalidate equations in some transactions. Most of Picoult's colleagues at other companies are physics PhD's. (Session L1)

VIEWING BIOMOLECULES BENEATH THE SURFACE
In research that can provide new insights into gene expression and the molecular mechanisms of disease, Vasilis Ntziachristos of Harvard Medical School and Massachusetts General Hospital ([email protected]) will describe a non-invasive method for three-dimensionally resolving tiny amounts of fluorescent molecules buried centimeters deep in living tissue. Called fluorescent molecular tomography (FMT), the technique shines light through tissue and uses a CCD camera to detect fluorescent markers and measure optical properties of tissue. By shining the light at several angles, Ntziachristos and colleagues can build 3D "tomographic" maps of the concentrations of fluorescent molecules. In recent experiments, the researchers could non-invasively resolve molecular function in small cancer lesions located deep in the brains of living mice. FMT can potentially quantify molecule-scale information on the development of certain diseases and the effects of treating those diseases. With further development, FMT could sense pico- to femto-mole quantities of fluorescent markers in humans as well.(P10.004)

HOMELAND SECURITY
Forefront physics research has contributed to vital technology used in national defense. Session P2 features scientists from four national labs and talks on nuclear testing negotiations, providing necessary technical means of verifying treaty components, and the development of large-area detectors for monitoring or searching for weapons-grade materials and high explosives.

IN ONE EAR
We are able to locate the origin of sounds thanks to the fact that we have two ears. Differences in the relative timing of sounds as well as differences in the volume level in each ear both affect our ability to pinpoint sounds. Surprisingly, timing and level differences seem to be independently processed by the brain. One of the central problems in studies of hearing is the mathematical modeling that accounts for the complex sound processing systems of that handle signals the ears pick up. William Hartman of Michigan State University will discuss parallel processing models that take into account the ways that our brains interpret timing and level differences of sounds (W9.4). Generally, explains Hartman, timing differences were assumed to be of primary importance for sound location, but in some cases the volume level differences may dominate. The issue is particularly important for hearing impaired people when the volume controls on hearing aids for each ear are independently adjusted. In effect, the adjustments that hearing impaired people make on their hearing aids continually deprogram and reprogram their brains, and may make it difficult for them to localize sound under certain conditions.

PLENARY TALKS
Five prominent physicists will look at the future of research in their respective fields. Frank Wilczek (MIT) will explain how the standard model of particle physics is incomplete and how the Large Hadron Collider (LHC), now under construction at CERN, will provide a chance to observe many new phenomena predicted by non-standard model physics. Noted cosmologist Michael Turner (Chicago) will speak about dark matter, cosmic rays, black holes and dark energy. Albert Libchaber (Rockefeller) will address biophysicists' apparent conflict between the search for universality in physics and the search for intricate details in biology. Advances in condensed matter physics, including the advent of new fields such as quantum electrical engineering and quantum computation will be addressed by Steven Girvin (Yale). Finally, David Gross (UCSB) will assess the possibility of testing the theory of superstrings and the search for extra dimensions. (Session F1)

LEFT-HANDED MATERIALS
Steps toward a "perfect lens" and lenses that bend microwave beams the opposite way to normal lenses have been taken by an MIT/Harvard collaboration (K22.1, K22.2). There is debate over whether or not these theoretically possible devices could actually be created, but the new experimental results put part of that debate to rest. Passing the microwaves through a slab of "left-handed material" (LHM), as these devices are known, results in a focused spot of microwave power, something that would not happen with normal right-handed materials. Other researchers from the University of Utah (K22.4) suggest that LHMs can be used for a new 3D imaging process.

MISCONDUCT IN PHYSICS
Recent evidence of professional misconduct in two different areas of physics has caused the community to think deeply about such issues. In November 2002, the APS Council approved new statements of professional ethics and revised its "Guidelines for Professional Conduct". A panel session, including members of the Lucent and Berkeley review committees will discuss these issues allowing time for input from the community. The session will be chaired by APS President Myriam Sarachik (CCNY-CUNY). Panelists include Malcolm Beasley (Stanford), Pierre Hohenberg (Yale), Arthur Bienenstock (Stanford), George Trilling (Lawrence Berkeley National Laboratory). (Session U1)

CARBON NANOTUBES - A TOOL FOR ALL OCCASIONS
Carbon nanotubes are now a huge focus of research and development with applications arising in diverse areas. They are being studied as ultrasensitive sensors of gas molecules in the environment, as opticalsensors, and as mechanical sensors that can detect very slight bending. Nanotubes are also being explored as the basis for electronic devices. Results will be presented for nanotube version of transistors, the basic element of electronics. As if these applications weren't enough, nanotubes can also emit x-rays suitable for medical use, and are useful for nanoextraction, as nanowicks, and for better microscopy (sessions K26, N26, V26, and X26).

ULTRAFAST LASER PULSES FOR CLEANER AIR
Modern cars often use catalytic converters to remove carbon monoxide from exhaust fumes. This is done by passing the gas over a platinum surface that encourages (or catalyzes) the chemical reaction turning carbon monoxide into carbon dioxide, a safer emission. However, understanding the process of the catalysis is challenging because it happens on a small physical scale over very brief periods. New techniques involving ultrafast laser pulses have been used to observe the chemical reaction happening and could lead to better technologies for cleaner air. (A11.6)

HIGHER BANDWIDTHS
Increasing the information capacity of communications systems requires an increase in "bandwidth," the frequency range over which the device operates. The current state-of-the-art 40-GHz bandwidth can't be pushed much higher using conventional choices of materials. Mark Lee of Bell Laboratories will describe how the properties of polymers as electro-optic devices allow bandwidths in the 150 to 200 GHz range with signals still measurable as high as 1.6 THz (=1600 GHz). (N18.5)

HIGHER-RESOLUTION OPTICAL MEDICAL IMAGING
Conventional medical imaging techniques, such as MRI and CT scans, can only see anatomical features as small as 0.1-1 millimeter. Far better resolution is required for diagnosing many medical conditions, including some important warning signs of heart disease and the early stages of numerous cancers. In many cases, it is important to see details less than 20 microns in size. Towards these ends, Nicusor Iftimia of Harvard Medical School ([email protected]) will present a host of high-resolution imaging techniques that employ fiber optics and light. The wavelengths of near-infrared and visible light, in the micron range and below, enable imaging of structures on those size scales. Working with Brett Bouma and Guillermo Tearney at Wellman Labs in Massachusetts General Hospital, Iftimia will describe three recently developed optical imaging technologies:(1) a catheter-based "optical coherence tomography"system which can potentially detect inflammation in atherosclerotic plaques and a possible early sign of esophageal cancer; (2) low-coherence interferometry (LCI) that can improve physicians' ability to locate breast cysts during a biopsy procedure known as fine-needle aspiration; and (3) "spectral encoded confocal microscopy" (SECM) which exploits a telecommunications technique known as WDM to make possible a high-resolution microscope small enough to travel through narrow body regions such as the esophagus but powerful enough to obtain images with sub-cellular detail. (P10.003)

SINGLE-MOLECULE BIOPHYSICS
Biology is a fruitful arena for physicists hoping to study fundamental science or to apply known physics principles in new ways. One example of this is the use of nanotechnology in exploring and mimicking the behavior of cells. Cells are complex systems with outer membranes separating them from a wider environment and an inner membrane surrounding the cell nucleus. Daniel Branton (Harvard) and his colleagues have created an artificial membrane consisting of silicon-nitride substrate with a nanopore only nm in diameter. Since DNA molecules are slightly negative in charge, they can be gently pulled through the pore using a positive voltage differential. Furthermore, since the chemical base units which help to form the backbone of DNA cause the conductivity of the pore to change in a characteristic way, it is possible to map the bases as they go through. Although single-base resolution monitoring of bases is not yet available, this method shows great prospect of speeding up the genome sequencing process. (Paper A10.1) See also http://mcb.harvard.edu/branton/index.htm.

IMPACT CRATER FORMATION
Although scientists can't do full-scale experiments with asteroids and planets, they can study impact craters through scale models that explain what happens in the planetary arena. UCLA physicists have experimentally studied how the size of a crater depends on the impact object, a vital piece of information in understanding past impact events (A13.002). The shapes of craters also provides information about an impact and Memorial University of Newfoundland physicists have developed a sequence of crater shapes that identify the energy of impact (A13.3). These results were obtained through experiments involving steel balls and glass beads.

JUMP-STARTING PHYSICS ENTREPRENEURS
"In the late 1990s, it seemed that any two graduate students and their dog could start and grow a high-tech company," says Cyrus Taylor (Case Western Reserve University), a featured speaker at session X6, about physics entrepreneurs. But with the collapse of the Internet and telecommunications sectors, the challenges facing new start-up firms have greatly increased. Taylor will describe his keys to survive and even thrive in this new environment, particularly the boost provided by new graduate programs that combine business school with physics training. He will be joined by Dennis Hamill of Nanotechnologies Inc., who will offer the small company perspective on moving a unique technology toward a commercial success, and Mark Zou of USA Instruments, who will describe how he took his fledgling company from humble beginnings to one of the country's 500 fastest-growing private companies.