March 2004

American Institute of Physics

Biggest physics meeting of the year

College Park, MD—Traditionally the biggest physics meeting of the year, the American Physical Society (APS) March Meeting will be held March 22-26, 2004 in Montreal. With over 6100 papers scheduled, this year's March Meeting is the largest ever. It is appropriate for the meeting to locate itself in Montreal since the international part of APS is considerable---more than one in five members are outside the U.S. and, in particular, more than 1000 APS members are from Canada. For decades the APS March Meeting has been the showcase for important physics discoveries, both those of a fundamental nature and those that result in practical innovations that form the backbone of modern technology. In yesteryear the hot topics were transistors, superconductivity, lasers, liquid crystals, and medical imaging. More recently the topics to watch, as far as future tech applications, have been magnetoresistance (at work in most magnetic hard drives), carbon nanotubes, versatile smart materials, self-assembled molecular layers, and quantum dots. What will it be next? Solid-state qubits, spintronic gates, cantilevers that weigh viruses, left-handed materials (with novel optical properties)? All these topics can be sampled by walking up and down the halls at this year's March Meeting. The menu of talks covers the full spectrum of physical reality on our planet: chemical reactions viewed in real time, turbulence in fluids, strange collective motions in granular materials, fuel cells and automotives, extended grid computing, new and novel materials, measurement science and detectors operating with unprecedented precision, polymers, DNA (and its many properties---electrical, mechanical, computational, etc.), and quantum gases.

WEBSITE AND PRESSROOM

The March Meeting website ( http://www.aps.org/meet/MAR04/baps/baps.html -click on "epitome" to view the sessions) offers a quick way to view hotel and travel information and all the abstracts. Complimentary press registration will allow science writers to attend all scientific sessions. If you wish to come, please fill out and return the form at the end of this release. Here is information relating to the press operations at the meeting:

The meeting pressroom will be located in the Palais des Congres de Montreal, room 521A
Press conferences will take place in room 521B
Pressroom hours: Mon-Wed (March 22-24 ) 7:30 AM to 5 PM and March 25 from 7:30 AM to 12 noon.
Pressroom phone numbers: 514-871-5930, 31, 32, 33
Pressroom fax number: 514-871-5834
Internet lines will be available.
Helpful tip for navigating through the online program and seeking contact information about individual speakers: First click on epitome. Then click on the session of interest. Then click on individual papers. Then click on the little camera at the top of the page. It should usually yield email contact information for the presenter of the paper.
Breakfast and lunch food will be available in the pressroom from Monday-Thursday (breakfast only on Thursday).

PRESS ACTIVITIES AT THE MEETING

During the week a number of press conferences will be held. A press conference schedule will be issued in early March, along with further tips about notable papers at the meeting (see also the list below). Science writers will be able to attend any regular invited- or contributed-paper session at the meeting. In addition we would like to mention two special events:

The AIP Science Writing Award for a broadcast item concerning research in the physical sciences will be presented on Monday, March 22, at 5 PM at a wine-and-cheese reception held in the news conference room (Room 521B). By fortunate coincidence, this year's winners happen to be from Canada.
A tour of several labs in Montreal will take place on Wednesday, March 24, beginning around 3 PM, leaving from the Palais des Congres. More details will be available later.
The heart of the meeting, for journalists, will be a series of press conferences. The topics are now being selected and a further press release will be forthcoming in about a month.
If you'd like to attend the meeting, please return the reply notice at the bottom.

THE FOLLOWING LONG LIST OF ITEMS IS INTENDED AS A SUMMARY OF POSSIBLE STORY IDEAS AND SELECTED HIGHLIGHTS AT THE MEETING. WRITERS NOT ATTENDING THE MEETING BUT INTERESTED IN ANY OF THESE STORIES CAN CONTACT AIP FOR MORE INFORMATION. FIRST A BRIEF ENUMERATION, THEN DESCRIPTIONS:

-Lowest-density solid
--Tolkien physics
-Cryogenic cabaret
-Hydrogen economy
-Skin at the cell-level
-Quantum dot coolers
-Superfluid waterfall
-Jet soot
-Blood-cell sorting
-Supersolid
-Nanotubes
--Canadian physics
-Plenary talks (incl. Fermionic condensate)
-Viruses
-Nanotrees
-Physics of landscape
-Harvesting sunlight
-Plastics under pressure
-Crawling cells
-High-end computing
-When solids go wrong
-Protein folding
-Face recognition
-Left-hand materials
-Physics in Brazil
-Fingertip MRI
-Landmines
-Woman pioneers
-Trumpets
-Paleo-dust
-Polymers under the influence

Lowest Density Solid Ever Reported
Blasting a high-power laser at disordered solid carbon has resulted in a new form of carbon, a cluster-assembled carbon nanofoam, in which saddle-shaped warped graphite-like sheets fill space at very low density. According to high-resolution electron microscopy images, the nanofoam consists of carbon-atom clusters (with an average diameter of 6-9 nanometers) randomly interconnected in a web-like foam. The nanofoam has some remarkable physical properties including the lowest measured mass density (~2 mg/cm^3) ever reported for a solid, making it even airier than aerogel. It also is a semiconductor, making it attractive for applications. However, the most salient property of carbon nanofoam is its unusual magnetic behavior. Unlike other forms of carbon, such as graphite and diamond, freshly produced carbon nanofoam is initially attracted strongly to a permanent magnet at room temperature. Although the "ferromagnetic" behavior at room temperature disappears after a few hours, it persists at lower temperatures. Nonetheless, this "ferromagnetic semiconductor" might have very useful applications for spintronics, the emerging field of devices based on a material's magnetic properties. The researchers of the Australian-Greece team that carried out this work (John Giapintzakis, University of Crete/IESL-FORTH, [email protected] and Andrei Rode, Australian National University, [email protected]) have concluded that the observed novel magnetic behavior is an intrinsic property of the carbon nanofoam and can be traced to its complex microstructure. Another possible application of the carbon nanofoam is in biomedicine, as tiny ferromagnetic clusters that could be injected in blood vessels may significantly increase the quality of magnetic resonance imaging pictures. (Paper A17.005)

The Physics of Tolkien
The works of J.R.R. Tolkien can provide a creative means of demonstrating the relevance of science (especially astronomy) to non-science majors, according to Kristine Larsen of Central Connecticut State University, who has designed just such a course. For example, in order to add depth and realism to his mythological creation, Tolkien invented his own constellations, some of which correspond to actual star groupings, and the internal chronology of the "Lord of the Rings" trilogy was timed to the cycle of lunar phases. Also featured in the session is a presentation of a new type of Dunking Bird, the popular physics toy that operates on the chemical potential energy of unevaporated water. The new version operates on the same principle, but is not a heat engine. (L27.6)

Cryogenic Cabaret
Among the social highlights will be a Thursday evening performance of "Cryogenic Cabaret," the brainchild of emeritus professor Marcel LeBlanc, who has received the Royal Society of Canada's McNeil Medal for the promotion of science to the public. An expert in cryophysics, LeBlanc chills his audience with a -78 C blizzard, freezes liquid nitrogen by boiling, morphs into a dragon spouting -200 C vapors, and transforms soggy frozen cigars into torches. He also sings, levitates magnetic and electric coils, smashes rubber balls, and explodes hydrogen balloons, all in the interest of presenting the fundamentals of cryoscience to experts and lay audiences alike.

Hydrogen Economy
Hydrogen makes an excellent fuel. Combine it with oxygen and you get an explosion plus, as a benign waste product, a bit of water. However, unlike oxygen, which is plentiful in the atmosphere, hydrogen is rather more difficult to procure and not yet easily stored safely in a fuel-ready form. Nevertheless, President Bush has called for an increased effort to tame hydrogen as a versatile source of energy. Two sessions (m1, L39, and N5) address this issue. Mildred Dresselhaus (former president of the APS and of AAAS, and a DOE official in the Clinton administration) will summarize the whole field. Numerous other scientists will present the latest results from what is becoming an ever larger research enterprise, including the making of hydrogen and storing it in fuel cells and other forms.

Why Skin Turns to Leather
Using atomic force microscopy (AFM), a technique that enables researchers to view tissue at the molecular level, physicists have discovered a new reason for why skin (and other "epithelial" tissue that lines the surfaces in our body) tends to become more rigid with age. Going beyond merely cosmetic concerns, the loss of elasticity in epithelial tissue has been implicated in the development of many age-related diseases, such as hardening of the arteries, joint stiffness, cataracts, Alzheimer's disease, and dementia. Previously, researchers thought the reduced elasticity in epithelial tissue resulted mostly from increased chemical bonds (crosslinking) that occurred in extracellular matrix proteins, the "glue" that holds together cells in the tissue. But now, Igor Sokolov of Clarkson University ([email protected]) and his colleagues have found that individual epithelial cells themselves become more rigid with age. By developing a new AFM method for studying cells, they have found that the Young's modulus, a measure of rigidity, is 2-4 times higher in old (senescent) human cells as compared to young cells. The researchers hope this discovery can provide a new direction for the research into treatment of age-related diseases that involve loss of elasticity in epithelial tissue. (D8.014)

Quantum Dot Coolers
Chiou-Fu Wang of the University of California at Santa Barbara ([email protected]) will describe experimental attempts to laser-cool a nanometer-scale mechanical beam with quantum dots, tiny islands with electrons at very specific energies. This is the first attempt to use quantum dots to cool a solid object. The researchers embed indium arsenide (InAs) quantum dots in a mechanical beam that's 1 micron long, 140 nm wide and 70 nm thick. Heat causes the beam to vibrate. The vibrations in turn release phonons, the particles that carry vibrations at the nanometer scale. Meanwhile, the electrons in the quantum dots will absorb laser light that's just the right energy to enable it to reach a higher-energy state. If researchers send laser light at a slightly lower energy, namely the energy of the light minus the energy of the phonon, then the quantum dots will absorb the laser light plus the phonons. By absorbing the phonons, the quantum dots thereby remove heat from the mechanical beam. While there are other possible approaches to laser-cooling a solid, one potential advantage of this approach is that the beam structure and quantum dots are fabricated with existing semiconductor processing techniques. (A36.002)

Superfluid Waterfall
Superfluid helium flows down a surface very differently from classical fluids such as water. Researchers will show high-speed video and analysis of their superfluid "waterfalls." The superfluid helium flows down the slope with an acceleration very close to constant, like an ideal case of zero friction. Water or mercury tends toward a constant speed or even slows as it flows down a slope. (D15.012)

Jet Soot
Soot emissions from engines are usually measured during stable operating conditions. New data shows that the emissions can change wildly during throttle changes and while the engine is warming up. Researchers have developed a mobile device for measuring the soot from jet and rocket engines, emissions that have the potential for considerable environmental and health impacts. (D33.13)

Fast Blood Cell Sorting
A blood sample consists of many components, from blood cells to plasma, viruses and proteins. Fast genetic analysis on a microchip requires separation of the wheat from the chaff. Researchers have developed a microfluidic device that continuously separates a flow of specific cells from the unwanted blood components as it passes over an array of micro-magnets. (H39.014)

Supersolid
Physicists recently announced the discovery of a supersolid - a material that is solid yet has a frictionless "flow" inside it. Solid helium-4 confined in pores in Vycor glass shows this strange "supersolid" behavior. As the glass is rotated, the solid helium-4 stays still, essentially meaning that the one solid flows through the other, but with no friction. (H15.009)

Nanotube Performance
Nanotechnology is now mainstream but how do you compare the performance of new materials made from carbon nanotubes to their conventional semiconductor predecessors? So far there have been no defined figures-of-merit for measuring the differences. Researchers are proposing a way to quantify the relative performance of these new materials and decide whether the new materials provide a significant improvement over the conventional. (A16.011)

Physics Up North
The history of physics in Canada will be recounted in session D5. Among the personages featured will be John McLennan, who built the physics department at the University of Toronto into a major research laboratory, conducting research on superconductors and liquid helium. German émigré Gerhard Herzberg is another featured Canadian physicist, a pioneer of molecular spectroscopy who built the world-class Spectroscopy Laboratory for Canada's National Research Council and conducted seminal research on the spectra of free radicals. And from 1950 to 1962, Bertram Brockhouse carried out research that laid the foundation for the field of inelastic neutron scattering at Chalk River Laboratories, inventing many new instruments and techniques in the process.

The Unity of Physics: Plenary Talks
Leading physicists will discuss the connections within physics and between physics and other sciences in a special series of presentations on the evening of Monday, March 22. Discussions will connect superfluidity to the stars, neutrinos to volcanoes to life on Mars, electronic devices to the brain, and more. Deborah Jin (NIST) will discuss her new "fermionic condensate." (Session G1)

How Viruses Pack Their Punch
To a physical scientist, viruses are among the most beautiful and intriguing biological structures. Thanks to a toolbox of biological, chemical, and physical techniques, scientists have been making fascinating quantitative measurements of virus properties. Studying bacteriophage, viruses that infect bacteria such as E. coli, a UCLA-Caltech collaboration (Rob Phillips, [email protected]) have been directly measuring the immense amount of pressure inside the virus's capsid, the tiny, 500-angstrom-wide protein shell that manages to store a 10-micron-long strand of DNA. According to Phillips, this masterful DNA-packing job is analogous to putting 500 meters of cable from the Golden Gate Bridge in the back of a FedEx truck, a task that's made even more impressive since the DNA is stiff and electrically charged. Embarking on a joint adventure of experiment and theory, Phillips and colleagues are striving to understand how the DNA gets physically scrunched into the capsid--and what biological purpose it serves. Their experimental measurements show that the DNA-stuffed capsid can exceed 50 atmospheres of pressure, or about 750 pounds per square inch. These immense pressures may explain how the viruses are able to release their DNA so forcefully into a host cell. The bacterial viruses being studied are an ideal "model system" which might lead to similar insights into other viruses. (A7.004)

Light-Harvesting Nanotrees
All kinds of devices are being shrunk to the nanoscale. For instance, researchers who developed a kind of nano-velcro made from carbon nanotube hooks report their findings that this nano-velcro is stronger than currently available welding techniques for connecting components of other nanoscale devices (W16.010). Other researchers have created nanoscale conveyor belts, which could be useful in the construction of other nanodevices. By driving electrical current through carbon nanotubes, researchers were able to controllably move indium metal along the tubes (W16.011). Another group has built magnetically actuated nanomotors (W16.014). And one group from Lund University in Sweden reports being able to grow nanotrees. The researchers developed a method of growing branched structures from semiconductor nanowires. They found that they could control the thickness, length, and chemical composition of each branch. It may even be possible to mimic photosynthesis and design functional, light-harvesting nanotrees (U16.014).

The Physics of Landscape
From Martian gullies to the Mississippi river, channels are a ubiquitous feature of landscapes shaped by erosion. They can range in scale from centimeter-sized rills to continent-sized rivers. However, scientists lack a comprehensive understanding of how channels form. Because real landscapes typically evolve too slowly for changes to be observed, erosion is usually studied by observing a static landscape and inferring its evolution. Now, researchers at MIT and Clark University (Alex Lobkovsky, [email protected]) have constructed a simple laboratory model of an eroding landscape and strive to understand it completely. In their experiment, water flows through a pile of identical glass beads that don't stick to one another. When the water emerges on the surface, channels form and grow deeper and wider. They use a laser-based technique to obtain an evolving topographic map of the surface of their glass landscape. Their quantitative studies reveal that nearly all channels grow in a similar fashion. Given a known source of water, their model then predicts how the channel forms and evolves. The results should be applicable to understanding the fundamental mechanisms of landscape erosion. (A18.010)

Corralling Sunlight
A thin coating on glass that collects the energy of sunlight by way of embedded dyes could offer an alternative to expensive photovoltaic cells, the traditional workhorse of solar energy. Researchers have incorporated a triple dye combination into these "luminescent solar concentrators" and improved the power generation efficiency of the technology by 36 percent. (H39.006)

Plastic Under Pressure
Anne Mayes of MIT ([email protected]) and her coworkers will discuss the experimental production of baroplastics, a new type of material that is molded into desired shapes through the use of high pressures, rather than the high temperatures which conventional plastics require. If further developed into a commercially available, widely used form of plastic, these materials have the potential to greatly reduce energy consumption in plastics manufacturing. Since baroplastics avoid exposure to elevated temperatures, the new materials can potentially be recycled more often than traditional plastics without losing their quality. The researchers have created baroplastics in a couple of different ways, as "block" copolymers composed of two distinct polymer components, and as nanoparticles with a core shell. Mayes and her colleagues Juan Gonzalez and Sang-Woog Ryu will discuss the ongoing investigations on these new materials in three talks (P4.005, B30.011, Z29.002).

Crawling Cells
Cell crawling is the chosen mode of transport for many complex (eukaryotic) cells. For example, white blood cells crawl as they track down pathogens in the bloodstream. After you suffer a wound, fibroblasts "pull" the skin back together with their collective crawling motions. Yet the general mechanism by which cells crawl is fairly complex. Inside eukaryotic cells there is a meshwork of proteins, called the cytoskeleton, which helps maintain structural integrity in the cell. Interacting with numerous other proteins, the cytoskeleton constantly reorganizes itself to "push out" the front of the cell and "pull up" the rear. Striving to understand how the cytoskeleton restructures itself to produce force and move in the right direction, Charles Wolgemuth of the University of Connecticut Health Center ([email protected]) and his colleagues study the simplest cytoskeleton, found in the sperm cells of nematodes (microscopic worms). The nematode's sperm cells crawl to reach the egg, as opposed to mammal sperm cells, which swim. The group models the cytoskeleton as a gel, a grid of connected protein filaments surrounded by fluid. Taking into account the physics of gels as well as known biological processes (such as the adhesion of proteins to cells), the researchers' model correctly captures two important features of nematode crawling: it produces sufficient force for the cells to move at observed speeds; and second, it produces a crawling cell that maintains its shape, which is what nematode sperm cells are observed to do. (B8.004)

High-End Computing
Computer simulations have become an important means of scientific discovery. In some areas computation may be even more accurate and cost effective than experiment. Ralph Roskies of the Pittsburgh Supercomputing Center will discuss how the increase in power and affordability of high-end computers has transformed the role of computation in many areas of physics (S2.001). Ray Orbach, director of the U.S. Department of Energy Office of Science will talk about the how important advances in basic science will be accomplished by an ultrascale scientific computing capability (USSCC). Orbach will describe preliminary progress on the successful grants in the NERSC competition for Innovative and Novel Computational Impact on Theory and Experiment (INCITE) (s2.002). Peter Freeman will discuss the data, networking, and software needed to support high-end computing and the National Science Foundation's efforts to develop this cyber infrastructure (s2.003).

When Solids Go Wrong
In one example of the use of computer simulations, Farid Abraham of IBM has run simulations with millions of atoms on some of the world's fastest computers to study how solids fail. His research investigates the dynamics of brittle and ductile solids at the atomic level, giving new insight into how materials crack. (S1.004)

Solved Protein Folding Problems
Determining how proteins fold into organized structures is a challenging and important problem. While much work remains to be done, many parts of this problem can be considered solved, according to Peter Wolynes of the University of California, San Diego, thanks to an approach known as energy landscape theory. Wolynes will describe how energy landscape theory has allowed researchers to better predict protein structure and design sequences of amino acids that can rapidly fold into a given structure. (S1.005)

Face Recognition
Most face recognition techniques are sensitive to lighting, shadows, or modification of appearance by makeup, natural aging or surgery, but in paper V10.010, researchers demonstrate that a technique called Digital Image Speckle Correlation (DISC) avoids these problems and can reliably identify faces. Human skin has a natural pattern of pores that is easily visible with conventional digital cameras. With DISC researchers can analyze these digital images and recognize the underlying muscle structure, which is unique to individuals and is not affected by lighting or makeup. This method could also be useful for medical diagnoses or early detection of facial paralysis or skin disorders.

Left Handed Materials
Discovered four years ago, so called left-handed materials possess a negative index of refraction, which causes light rays to deflect in a direction contrary to what normal optics would predict. A planar slab of such a substance should possess novel optical properties, perhaps the most practical being the ability to bring light rays from a source to a sharp focus. That is, compact, flat lenses without any special shaping might be possible. This would be a boon for wireless communications, especially in improving delay lines, antennas, and filters. Session P19 features experimental and simulation studies of the odd optical properties and efforts to integrate negative-index materials into prospective photonic devices.

Synchrotron Radiation in Brazil
Exploring nature at extreme conditions (high magnetic field, for instance, or very low temperatures) or illuminating a sample with special beams (such as intense x rays or neutrons) is often too expensive for many labs. That's where government user facilities, with their pooled resources, come in handy, especially in developing nations. Session A3 looks at how synchrotron radiation works in various countries. Speakers come from Armenia, Brazil, Thailand, and from the SESAME lab to be located in Jordan (http://www.sesame.org.jo/). Session A3 also includes a panel discussion with George Atkinson (US Department of State), Neal Lane (Rice University, and former presidential science advisor), Ernest Moniz (MIT and former DOE official), and Ray Orbach (Office of Science, Department of Energy).

Fingertip MRI
Superconducting Quantum Interference Devices (SQUIDs) have found application as highly sensitive sensors and detectors, and are now being applied in magnetic resonance imaging (MRI) applications. Researchers at UC-Berkeley and Lawrence Berkeley National Laboratory have acquired two-dimensional images of water, mineral oil phantoms and pepper slices in less than two minutes by performing MRI with a low-Tc SQUID detector. The new system is ideally suited for imaging small, peripheral parts of the human body, such as fingers and wrists. The team has also demonstrated ultra-low-field MRI using an untuned SQUID detector, achieving 1-mm resolution images. Both results will be discussed at the meeting. (Session A39)

Navigating Landmines
Because of their ease of employment, lost cost, and effectiveness, land mines have become an almost ubiquitous weapon in the last 50 years. There are now more than 45 million potentially threatening land mines around the world, and new mines are being placed much faster than they can be removed, so the problem is worsening. Current estimates of casualties resulting from land mines exceed 15,000 per year, and many are civilians, even children. Thomas Altshuler of Rockwell Scientific Company will provide an overview of the issue, and Frank Rotondo of the Institute for Defense Analyses will discuss advances in new detection technologies, including ground-penetrating radar, improved electromagnetic induction metal detectors, nuclear-quadrupole resonance and acoustic/seismic detectors. (Session D39)

Pioneering Women Physicists
The meeting will feature several talks on pioneering women in physics. Monday afternoon will feature a presentation on Canada's first woman physicist was Harriet Brooks, who worked under both Ernest Rutherford and J.J. Thomson at Cambridge University's famed Cavendish Laboratory, and later worked with the Curies in Paris. She investigated the nature of "emanation" from radium; discovered that radioactive substances could undergo successive decay; and first reported the recoil of the radioactive atom, at a time when women in science were few and far between. On Wednesday morning, various speakers will talk about the lives and accomplishments of Agnes Pockels - a German-born woman scientist who pioneered studies of surface science, particularly monolayers at the air/water interface - and Katharine Blodgett, the first woman scientist to join the GE research staff, and the first to obtain a doctorate from Cambridge University's prestigious Cavendish Laboratory. (Sessions D5, N7)

Trumpet Fanfare
Scientists from SUNY Genesco are exploring the connections between trumpet playing and the quality of the sounds produced, which are poorly understood. For example, they are studying the force with which the instrument is pressed against the lips, especially to hit higher pitches, which vary greatly among different players, sometimes by a factor of three or four. The team has modified a trumpet to enable them to monitor the force applied by players of all skill levels, along with the sound spectrum and players' facial expressions. (Session D39)

Paleo-Dust
Scientists from the University of California, Berkeley, have developed a new paleoclimatological instrument called the Dust Logger. The instrument is a spinoff of the Antarctic Muon and Neutrino Detector Array (AMANDA) project, a collaboration that searches

Polymers Under the Influence
Like many APS March Meeting symposia, Session B4 touches upon not only physics, but also chemistry and biology: it explores the behavior of one-dimensional polymer chains and two-dimensional polymer membranes in the presence of ions. This basic research area has enabled better understanding of how to make efficient plastic batteries (B4.001); insights on a new family of surfactants (the substances used as soaps and many other useful chemicals) (B4.004), the construction of novel devices for analyzing biological molecules such as DNA (B4.002), and new knowledge on the factors that govern the biological activity of cell membranes (B4.004) and proteins (B4.005).

David Harris, Ernie Tretkoff, and Jennifer Ouellette of APS also contributed to the preparation of this press release.

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APS 2004 March Meeting

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For more information contact Phillip F. Schewe, 301-209-3092, [email protected] or Ben Stein, 301-209-3091, [email protected] at the American Institute of Physics.