Physicists Head to Austin for APS March Meeting
The biggest physics meeting of the year, the APS March Meeting, rumbles into Austin, Texas during the week of March 3-7, 2003, featuring an estimated record 5735 talks in a broad range of fields, including materials and condensed matter physics, biological physics, atomic, molecular and optical physics, computational physics, instrumentation, and many others.
The meeting is also traditionally a showcase for 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.
In addition, there will be sessions on various non-technical topics-such as the history of physics, international physics, physics education, and current issues such as homeland security and scientific ethics -as well as numerous special events [See sidebar further down on this page]. A broad-brush sampling of some program highlights follows; more extensive reporting on specific events at the meeting will appear in future issues of APS News.
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 temperature. Four groups report on new magnetic refrigerators that operate with one tenth of previous field strength at usable temperatures. One group finds a 12x Celsius cooling effect and achieves temperatures below freezing. [Session K7]
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 optical sensors, as mechanical sensors, and as the basis for electronic devices. At the March Meeting, one can hear results on the nanotube version of transistors, the basic element of electronics. Nanotubes can also emit x-rays suitable for medical use, and are useful for nanoextraction, as nanowicks, and for better microscopy. [Sessions B27, N26, K26, V26]
Forefront physics research has contributed to vital technology used in national defense. A special session 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. Among the speakers is C. Paul Robinson of Sandia, this year's recipient of the George E. Pake Prize. [Session P2]
Physics principles can be used for fun and profit in elucidating many aspects of everyday life. Conversely, some of the more glamorous aspects of mass culture can be used to help teach physics, as evidenced by a special session on physics in comics, baseball and Hollywood. The three speakers are James Kakalios (University of Minnesota) who teaches a course in the "science of comic books," [See profile, Physics Today, November 2002]; Robert Adair (Yale University) who has written a book on the physics of baseball; and the author of The Physics of Star Trek, Lawrence Krauss (Case Western Reserve University), talking about physics in movies and on TV. [Session 3A]
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". [See APS News, January 2003].
A panel session, including members of the Lucent and Berkeley review committees, confronts these issues, with time allowed for audience participation. The session, chaired by APS President Myriam Sarachik (CCNY), includes panelists Malcolm Beasley (Stanford), Pierre Hohenberg (Yale), Arthur Bienenstock (Stanford), and George Trilling (Lawrence Berkeley National Laboratory). [Session U1]
DREAMS FOR THE FUTURE OF PHYSICS
This is an exciting time to be a physicist, as technological advances revolutionize many subfields and even promise to spin off new ones. In session F1, chaired by Marvin Cohen, APS Vice President, Frank Wilczek (MIT) contends that it is becoming increasingly clear that the standard model of particle physics is incomplete. The Large Hadron Collider under construction at CERN will provide a chance to observe many new phenomena predicted by non-standard model physics. Wilczek also tackles the future of nuclear physics, which lies with QCD and opens the possibility of understanding matter at extreme temperatures such as those found in the Big Bang.
According to Michael Turner (University of Chicago and Fermilab), these new possibilities have deep ties to astrophysics and cosmology, a field which will try to answer questions about dark matter, cosmic rays, black holes and dark energy.
In biophysics, says Albert Libchaber (Rockefeller University), there is an apparent conflict between the search for universality in physics and the search for intricate details in biology.
Steve Girvin (Yale University) explains how progress in condensed matter physics has been driving new technology, which has in turn been advancing the field even further and increasing its relevance to other fields, particularly elementary particle physics.
Advances in accelerator technology could lead to experimental tests of string theory by observing supersymmetric particles or extra dimensions, according to David Gross (UCSB). [Session F1]
March Meeting Special Events
Sunday, March 2
Monday, March 3
Tuesday, March 4
Wednesday, March 5
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" that can carry genetic instructions. Like proteins, RNA can fold into enzyme-like molecules that catalyze important biochemical activities.
At the meeting, researchers present intriguing findings on the folding properties of RNA. Ranjan Mukhopadhyay 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 a hypothetical RNA sequence 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 (Ohio State University) and Terence Hwa (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. Exploring how different organisms produce the same RNA structures from different sequences, Erik Schultes (Whitehead Institute of MIT) will discuss experimental evidence of "neutral networks," harmless changes in RNA sequence that still produce the same folds in an RNA molecule. [Session G10]
STORING AND 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) show how a Bose-Einstein condensate (BEC) can store and process optical information. This may be the first step toward quantum computation in BECs. Other researchers present the latest results on trapping arrays of BECs for use in quantum information processing. [Sessions H4, K34.004]
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 March Meeting features the latest word on photovoltaic re-search. Allan Barnett (AstroPower, Inc.), CEO of the largest company dealing exclusively with photo-voltaic products, provides an introduction to the subject.
Other speakers describe how plastic solar cells can be integrated into clothing and power mobile phones, and report on new 2nd-generation devices and on the process by which 3rd-generation materials will be winnowed. [Session A8]
Evan Picoult earned a PhD in particle physics but 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 equations in some transactions.
Other topics at the session are credit risk models, theory of risk management, and basic methodological issues and numerical methods for the practical implementation of risk calculations for financial derivatives. [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 (Harvard Medical School and Massachusetts General Hospital) describes 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. [Session P10.004]
Steps toward the "perfect lens" and lenses that bend microwave beams the opposite way to normal lenses have been taken by an MIT/Harvard collaboration. Much debate has surrounded whether or not these theoretically possible devices could actually be created but these 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 from normal right- handed materials.
Other researchers from the University of Utah suggest that LHMs can be used for a new 3D imaging process. A Naval Research Laboratory scientist moves to the microscale to discuss the possibilities for incorporating LHMs into electronics and the new types of electronic devices that will be possible. [Session K22]
IMPACT CRATER FORMATION
Although scientists can't do full-scale experiments with asteroids and planets, they can study impact craters through scaled 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. 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. [Session A13]
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 optical sensors, as mechanical sensors, and as the basis for electronic devices.
At the March Meeting, one can hear results on the nanotube version of transistors, the basic element of electronics. Nanotubes can also emit x-rays suitable for medical use, and are useful for nanoextraction, as nanowicks, and for better microscopy. [Sessions B27, N26, K26, V26]
ULTRAFAST LASER PULSES FOR CLEANER AIR
Modern cars often use catalytic converters to remove carbon monoxide from exhaust fumes. 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. [A11.006]
CAN YOU HEAR ME NOW?
Increasing the information capacity of communications systems requires an increase in "bandwidth". The current state-of-the-art 40 GHz bandwidth can't be pushed much higher using conventional choices of materials, so researchers are exploring high band- width options. Mark Lee (Bell Laboratories) describes 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). [Session N18]
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 (Harvard Medical School) presents 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. [Session P10]
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. This method shows great prospect of speeding up the genome sequencing process. [Session A10]
OUT OF AFRICA
Physicists in African universities are confronted with daunting challenges in their efforts to train students and conduct research, according to Kennedy Reed (Lawrence Livermore National Laboratory), this year's recipient of the APS Wheatley Award for his work in that region.
He outlines recent efforts at developing the scientific infrastructure in Sub-Saharan Africa, as well as efforts to encourage scientific links between physicists in the US and those in Africa.
Other speakers discuss fostering new partnerships between the U.S. and African physics communities, the economic and technological development of African countries, and new initiatives by the NSF and other agencies to promote materials physics in the southern regions of the continent. [Session H2]
START ME UP
"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 a Thursday afternoon session on educating physics entrepreneurs.
But with the collapse of the Internet and telecommunications sectors, the challenges facing new start-up firms have greatly increased. Taylor offers his keys to survive and even to thrive in this new environment.
He is joined by Dennis Hamill (Nanotechnologies Inc.), who gives the small company perspective on moving a unique technology toward a commercial success, and Mark Zou (USA Instruments), who reveals how he took his fledgling company from humble beginnings to one of the country's 500 fastest-growing private companies. [Session X6]