APS March Meeting Press Conference Schedule

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Physics Press Conferences Schedule
American Physical Society March Meeting --
Dallas, Texas, March 21-25, 2011
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EMBARGOED. Each section of this release is embargoed until the time of the corresponding press conference.

The following press conferences will take place during the March Meeting of the American Physical Society (APS), to be held March 21-25, 2011, in the Dallas Convention Center. Journalists are invited to attend the meeting free of charge. Registration information can be found at the end of this release.

All press conferences will be held in Rooms A125/126 of the Dallas Convention Center.

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BRIEF SCHEDULE OF PRESS CONFERENCES

Mon
--11:00 a.m., Material Advances, Sessions A28, A44, B28,
--12:30 p.m., Superconductivity, Sessions 1B, A5
--2:30 p.m., Graphene Devices, Sessions A30, B37

Tues
--9:30 a.m., Physics of Economic and Social Networks, Sessions B14, J7
--11:00 a.m., Understanding Cancer, Sessions H39, D21
--12:30 p.m., Texas Physics, Session H8
--2:00 p.m., Tiny Components and X-Ray Detectives, Sessions B32, L2,W21

Wed
--10:00 a.m., Countering WMDs with Physics, Session Q5
--1:00 p.m., Graphene Theory and Nobel Laureate, Sessions A2, U1, Q27, T2
--2:30 p.m., Homeland Security, Sessions W54, Z39



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MONDAY PRESS CONFERENCES
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Monday, March 21, 11:00 a.m.
MATERIAL ADVANCES
Novel materials, from smart metals to self-healing plastics, are the subject of a significant fraction of the research presented at the APS March Meeting every year. Among the thousands of material advances on tap is one that may lead to the toughest fabrics ever made. The key to the new material is fiber made of bundles of carbon nanotubes. Tobin Filleter (A28.00005) and colleagues at Northwestern University have developed methods to make nanotube threads and twine tougher still by exposing them to electron beams that cause the fibers to form microscopic mechanical bonds known as crosslinks. The crosslinked fibers are as much as ten times stiffer and stronger than non-irradiated fibers. Vasav Sahni (A44.00009) and colleagues at the University of Akron have taken a lesson from nature by investigating spider adhesive to reveal how the polymer material is both strong and flexible. After gaining an understanding of how the spider glue functions, the team was successful in mimicking the glue in the lab. Finally, Ming Xu (B28.00007) and colleagues at the Technology Research Association for Single Wall Carbon Nanotubes (TASC) and National Institute of Advanced Industrial Science and Technology (AIST) in Japan have developed a new viscoelastic (or rubber-like) material built entirely of carbon nanotubes that retains its properties over a record temperature range, from -196 C to 1000 C. The material could be incorporated into craft headed to interstellar space, used inside high-temperature furnaces, or perhaps as high performance parts in airplanes and other vehicles. Xu will discuss the likely mechanisms behind the viscoelastic’s record-setting temperature range as well as describing new methods the group has developed for creating softer, more elastic and stronger versions of the material.


Monday, March 21, 12:30 p.m.
SUPERCONDUCTIVITY
This year is the centenary of Kamerlingh Onnes’s discovery of superconductivity. To celebrate, this briefing looks at some of the practical benefits of materials that conduct electricity without the loss of energy to resistance. Examples include superconducting motors (the U.S. Navy plans to convert to all-electric propulsion, where low-footprint superconducting motors would be a boon), superconducting transistors (leading perhaps to “super-spintronics,” technology that takes advantage of the spin of electrons), lower-power MRI machines, high temperature superconductor (HTS) power lines capable of carrying power densities 100 times that of the capacity of copper, and HTS generators for offshore wind turbines.
Speakers: George Crabtree (1B.00001) of Argonne National Laboratory, and co-chair for the Department of Energy’s assessment of applied energy programs; Oleg Mukhanov (A5.00002) of Hypres, Inc.; Kathleen Amm (1B.00003) of General Electric.


Monday, March 21, 2:30 p.m.
NEW GRAPHENE DEVICES
Graphene was celebrated last year with the award of the Nobel Prize for physics to Andre Geim and Konstantin Novoselov a scant six years after their pioneering work on the ultra-thin, strong, and electronically versatile material. Many research groups have now made progress towards practical graphene-based devices that could eventually make conventional silicon electronics obsolete. Among the recently-developed graphene devices being announced at the 2011 March Meeting are radio frequency transistors (Han Wang, MIT, B37.00001), logic inverters (Song-Lin Li, National Institute for Materials Science, Japan, B37.00004), and graphene-based photodetectors (Allen Hsu, MIT, A30.00011). In addition, Walt de Heer of the Georgia Institute of Technology will offer a broad overview of graphene based electronics (B37.00007).



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TUESDAY PRESS CONFERENCES
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Tuesday, March 22, 9:30 a.m.
PHYSICS OF ECONOMIC AND SOCIAL NETWORKS
Physicists are developing innovative techniques for analyzing complex economic and social behaviors, several of which will be presented in this press conference. Richard Wiener (B14.00005) of the Research Corporation for Science Advancement in Tucson, Ariz. will describe a simple mathematical model of competition among members of social groups. It predicts, for example, that in many modern secular societies, religions will continue to lose members and be driven toward extinction. Looking at other networks, the time it takes light to travel between stock exchanges in New York and London (and other cities) has become a limiting factor for high-frequency financial trading. Alexander Wissner-Gross (B14.00002) of Harvard University presents a new strategy that partially overcomes this limitation by positioning computers at specific geographic locations worldwide, including in oceans or other sparsely networked regions, to serve as network coordinators. The strategy could also improve Internet access worldwide. César Hidalgo (J7.00005) of the Massachusetts Institute of Technology summarizes recent research that describes and explains the evolution of the mix of products that countries produce and export and allows for predicting a country’s future industries.He will describe the factors in studying economic complexity and introduce a simple model to account for them.


Tuesday, March 22, 11:00 a.m.
UNDERSTANDING CANCER
The study of cancer and the search for a cure are getting an assist from physical science laboratories. The initiation and progression of a tumor is a complex process, resembling the growth of an embryo. Typically, scientists view cancer cells as rogue individuals violating the rules of the game, but Robert Austin (Q7.00001) of Princeton University suggests that what we see is actually a programmed process. He asks whether tumor progression is dominated by the random acquisition of successive survival traits, or, as he concludes, by a systematic and sequential unpacking of “weapons'' from a pre-adapted ”toolkit'' of genetic and epigenetic potentialities. Epigenetic cancer is caused not by changes in the DNA, but instead by chemical modifications. Robert Riehn (H39.00001) of North Carolina State University also studies epigenetic cancer development. He has developed nanotechnologies to map epigenetic changes on single DNA and chromatin, or pre-chromosome, strands. This approach is central to studying the variety of cells in cancer since rapid changes in epigenetic makeup, done by rare cancer stem cells, is a hallmark of cancer's progression. Liyu Liu (H39.00005) of Princeton University targets the truly fatal part of cancer: metastasis, or the invasion of cells into other areas. Her work was inspired by the "islands in the sky" of the Venezuelan Tepui, isolated mesas where it was thought that evolution has stood still. Her approach is to probe cell invasiveness using 3D microscopic imaging of silicon microchips. She has observed some remarkable collective cell behaviors, with the help of confocal microscopy, a technique using lasers to produce high resolution images.


Tuesday, March 22, 12:30 p.m.
TEXAS PHYSICS
David Hanson (H8.00001) of Hanson Robotics, located near Dallas, will discuss the development of robots employing the latest understanding of cognition that will make good toys and eventually even companions. These robots, he maintains, are enough like humans in their responses so as to appear autonomous and not like a machine. Stephen Wharton of Skycam, Inc. (H8.00002) will describe X Power graphics, a data system used on the ESPN network to enhance rodeo coverage. A puck-sized sensor, filled with accelerometers and gyroscopes, provides instantaneous measurements of a cowboy’s ride aboard a bucking bull or horse.


Tuesday, March 22, 2:00 p.m.
TINY COMPONENTS AND X-RAY DETECTIVES
Niek van Hulst (B32.00004), of the Institute of Photonics Sciences (ICFO) in Barcelona, will describe recent advances in the development of nanoantennae, tiny antennas that can transmit photons in various patterns. The antennae operate much like the old fashioned TV antennas that once sprouted from most rooftops, except that they are millions of times smaller. The tiny antennae might detect signals emitted by biological molecules or be used in quantum computers. Mark Reed (L2.00003), of Yale University, will discuss their creation of the first transistor constructed from a single molecule. Single molecule transistors are the smallest possible transistors, which may someday help take computers to the limits of computing power while simultaneously reducing their costs. Robert Thorne (W21.00013), of Cornell University, will talk about exposing traces of ancient markings on Mayan, Greek, Roman and other artifacts using a non-destructive technique called X-ray fluorescence (XRF) imaging. The technique allows high resolution imaging of chemical traces left behind by tools and paints invisible to the naked eye.


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WEDNESDAY PRESS CONFERENCES
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Wednesday, March 23, 10:00 a.m.
COUNTERING WMDs WITH PHYSICS
Physicists and other scientists made weapons of mass destruction possible, and they also play leading roles in controlling them and limiting their danger. Two examples of physicists' latter contributions will be presented at this press conference. Physicists can predict the means and risks of the removal of nuclear weapons. Jay Davis (Q5.00004), president of the Hertz Foundation, which provides fellowships to students in the physical, biological and engineering sciences, says physicists can undertake systems analysis to help guide policy and operations: what are the risks, what should inspectors look for, what dangers might be lurking in a new technology or an unexpected development? He will discuss how physicists can enter this challenging field. Regarding biological weapons, Philip Wyatt (Q5.00003) of the Wyatt Technology Corporation in Santa Barbara, Calif., is upbeat. Despite what he says is the expectation that terrorists are going to be attacking us very soon, he is confident that the surreptitious introduction of a bioterrorist agent at a shopping mall, airport, or meeting place would likely be detected within a few minutes. Accordingly, he says, the dangers posed by such potential attacks will soon be minimized thanks to devices, like handheld mass spectrometers, developed to detect bioterrorist agents.


Wednesday, March 23, 1:00 p.m.
GRAPHENE NOBEL PRIZE LAUREATE
Konstantin Novoselov (U1.00001), who along with his University of Manchester colleague Andre Geim, won the 2010 Nobel Prize in physics for pioneering work on graphene - one-atom-thick sheets of carbon with remarkable electrical and mechanical properties. He will be joined at this briefing by Sankar Das Sarma, director of the Condensed Matter Theory Center at the University of Maryland (chair of sessions A2 and B1); Amir Yacoby (A2.00005 and http://meetings.aps.org/Meeting/MAR11/Event/141161) of Harvard University, who will discuss di-layer graphene which, unlike single-layer graphene, can be tweaked into behaving like a semiconductor, making it useful for making transistors; and Philip Kim (http://meetings.aps.org/Meeting/MAR11/Event/141720) of Columbia University.
A2
B1


Wednesday, March 23, 2:30 p.m.
HOMELAND SECURITY
Andrew Traverso (W45.00013 and W45.00014), of Texas A&M University, will speak about the development of a backwards-emitting laser-like beam that could be developed to identify gases and particles in the sky. Created in collaboration with colleagues at Princeton University and the University of Arizona, the beam could potentially be exploited for new types of remote sensing and may lead to a novel way to measure components of the atmosphere or search for airborne biological weapons, like anthrax spores, miles above the Earth without having to the leave the ground. Abhishek Kumar (Z39.00013), of the University of Massachusetts Lowell, will talk about a polymer that will make it easier to detect explosives in airports. The newly-developed fluorescent polymer responds to trace elements of explosives in the air. The polymer’s creators are working to produce a small commercial device that could be mass-manufactured and distributed broadly at a low cost, making airports around the world safer.


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MORE INFORMATION FOR JOURNALISTS
- General Meeting Information

REGISTERING AS A JOURNALIST
Science writers intending to go to the meeting should contact James Riordon at 301-209-3238 or riordon@aps.org about free registration. Onsite registration is possible in the pressroom throughout the meeting, but to speed the process journalists are encouraged to register in advance. Press badges can be picked up in the pressroom and will allow you to attend any session at the meeting.

PRESSROOM INFORMATION
A dedicated and staffed pressroom will operate throughout the meeting at the Dallas Convention Center. Phones, computers, printers, and free wireless Internet access will be available to reporters using the pressroom.
- Location: Dallas Convention Center, rooms A118/119; press conferences in A125/126
- Hours: MON-THU, 7:30 a.m. to 5:30 p.m. and FRI, 7:30 a.m. to noon
- Phone numbers: 214-853-8001, 214-853-8002, 214-853-8003, 214-853-8004
- Fax number: 214-853-8000
- Food service: Both breakfast and lunch will be provided on MON, TUE, and WED. Breakfast only will be served on THU, and coffee/tea will be available on FRI.

ABOUT APS
The American Physical Society (www.aps.org) is a non-profit membership organization working to advance and diffuse the knowledge of physics through its outstanding research journals, scientific meetings, and education, outreach, advocacy and international activities. APS represents 48,000 members, including physicists in academia, national laboratories and industry in the United States and throughout the world. Society offices are located in College Park, MD (Headquarters), Ridge, NY, and Washington, DC.

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LA12748

Electron Emission From Hydrogen Coated Diamond Linked to the Generation of Quantum Sound Waves

Diamond’s amazing physical hardness and ability to conduct heat are well known and understood. Less appreciated are its amazing electrical properties. When the surface of a high quality diamond is coated in atomic hydrogen, that surface becomes electron-phobic, with a so-called “negative electron affinity”. In this state it is relatively easy to remove electrons from the diamond in the form of an intense electron beam. Electron beams are vital to electron microscopes, electron accelerators and the free electron lasers currently under construction around the world. In spite of its potential technological importance, the mechanism by which this happens in diamond has until now been a mystery. In this paper we investigated this special kind of electron emission from a high quality, synthetic, “black” diamond. It was found in this paper that when the diamond is illuminated by a deep ultraviolet laser, the emission of electrons from the surface requires the simultaneous emission of high energy, high momentum quantum sound waves, called phonons, inside the diamond. This phonon emission effect may allow the construction of a simple and efficient SASER – a sonic laser – from diamond that can operate at and above room temperature. Additionally, the strength of this effect has implications for our understanding of how superconductivity, the flow of electrical current without resistance, arises in similar diamonds at very low temperatures.

LY12434

Quantum dance of a single atom with a miniature Bose-Einstein condensate

Predicting the movements of three interacting particles is a hallmark example for a difficult problem in classical mechanics - under most circumstances it is unsolvable. For example the mutually dependent orbits of the moon, the earth and the sun can only be predicted up to a certain accuracy. In the quantum world understanding such few-body systems is no simpler and the experimental investigation of their inner workings is very often complicated by their microscopic scales. An important example for quantum few-body systems are atomic nuclei, that consist of a small number of protons and neutrons; large particle accelerators are needed to explore atomic nuclei experimentally.

In our work, we accurately investigate the effects of interactions in an accessible model few-body quantum system with large length and low energy scales; ultracold bosonic Rubidium and fermionic Potassium atoms are trapped at the sites of on optical lattice, an artificial crystal made of laser light. On each site of the crystal a miniature Bose-Einstein condensate of Rubidium atoms interacts with a single fermionic Potassium atom. Using a novel, tricky detection scheme we accurately observe the interplay of interactions, finding that the presence of a single fermionic atom can also mediate interactions between the bosons. Our system may help to better understand theoretical models of atomic nuclei and shows the feasibility of advanced schemes of quantum computation and quantum memory, where one atomic species is used for data storage and the other one for the actual computation.


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EY10611

Spotting efficient broadcasters and receivers

Interactions such as ``who dated whom'', ``who phoned whom'', ``who emailed whom'', and ``who Facebook-friended whom'' do not remain static. They evolve over time. This can have important implications when we try to understand the spread of rumours, opinions, malware or diseases. If Amy meets Bob in the morning and Bob meets Coleen in the afternoon, then an infection, or a piece of gossip, can be passed from Amy to Coleen, but not from Coleen to Amy. If we don't keep track of the order of those interactions, then we can't make accurate summaries. In this work, we show how to incorporate time's arrow into the types of computer algorithms that are becoming widely usedin the field of Social Network Analysis. We apply this new technique to email data within the Enron corporation and cell phone data in a university laboratory, showing how to spot the efficient broadcasters (good places to plant a rumour) and receivers (good places to find out the latest rumour).

LW12245

Atomic friction: when experiments meet simulations

Sliding at the nanometer scale usually does not occur smoothly. Often, the two surfaces stick together and then slip unstably with atomic periodicity. Despite its crucial role in revealing the molecular origins of friction, atomic stick-slip frictional behavior is not fully understood. This is largely due to the fact that the detailed information of the sliding interface is buried and not easily accessible. Now, a collaborative research team has recently that key aspects of atomic stick-slip behavior observed experimentally for an ultra-sharp platinum tip sliding over an atomically flat gold surface can be reproduced consistently in simulations. The sliding conditions are optimally matched in the two systems and a special computational method was adopted to substantially slow down the model sliding speeds to approach those of the experiment. Comparisons of the results with theoretical models confirm that, at lower speeds, atomic friction is a thermally driven process. During this process, the atoms from the tip are hopping to nearby locations with the help of thermal vibration and with a frequency limited by their inertia. However, at high speeds, where most conventional atomistic simulations are run, frictional processes are not in this thermally-activated regime. This provides new guidance for comparing simulations and experiments focused on atomic-scale friction.

LA13215

Binary Bonds

By pulling on an individual atom with an atomically sharp probe, the smallest toggle switch achievable in silicon has been realised. The switch is flipped by reorienting a single chemical bond through mechanical force alone. Although atom switches have previously been reported by a number of research groups, in each case the switching mechanism has required, or involved, a flow of electrons. In this paper we show that a silicon atom can be toggled back and forth between an ‘up’ and a ‘down’ position by directly modifying the bond it makes with its nearest neighbour. This is achieved through manipulation of the force between two atoms – an electric current or a bias voltage is not necessary – and results in binary control of bond angle. The ability to switch the orientation of a single chemical bond in this way is an important new addition to the nanotechnologist’s toolbox.

EX10521

Wouldn't it be nice to have cars with enhanced response to impact without the need to use more material on them?

By analyzing a simple mechanical problem, the deformation of a membrane forced to go through a ring, we found that the mechanical response of a thin membrane depends on how deformed it is (packing fraction) as well as on its frictional properties. We showed that a highly deformed membrane can be rationalized as one that is slightly deformed but thicker than the original one and that the basic deformations of it are conical deformations, as previously found for the case of weakly deformed elastic plates. Most strikingly, we showed that friction plays an important role once a highly deformed membrane touches itself; the larger the friction the larger the mechanical response. Our study suggests that the modification of frictional properties of a thin plate, say by changing its texture or by making it stickier, is a promising an inexpensive route to enhance the mechanical response of thin walled structures subject to extreme deformations.

LZ12356

The problem of how to pack objects into a confined space is something that is familiar to every economy-class flyer. Surprisingly, such problems find a broad range of scientific and industrial applications - these range from the mundane, as for example the most efficient way to pack Chinese egg rolls in cylindrical containers , to the high tech, such as molecular self assembly (the process by which molecules are deliberately guided into forming novel nano scale structures, which are at the heart of a number of next-generation technologies). An important problem of this type is finding the densest packing arrangement of equal sized hard spheres in a cylindrical tube . In this letter we demonstrate a surprising connection between this problem and the analogous problem of packing hard disks on the surface of the cylinder. The approach relies on ideas borrowed from phyllotaxis, a branch of biology that seeks to explain the emergence of floral patterns, e.g. the arrangement of florets on the head of a sunflower. This work will help researchers understand a wide range of columnar structures, encountered across the sciences, including wet foams, novel colloids, viruses and microtubules.


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LU12663

Hand-Crafting Nanoparticles into Superstructures with Light

One of the Holy Grails of modern nanoscience is to assemble nanoparticles, tiny pieces of matter with diameters in the billionth of a yard range, into larger structures of any desired shape and form at will. Scientists have recently demonstrated a remarkably simple, elegant and cost effective way of achieving this goal via a process they term “Optically Directed Assembly” or ODA. ODA involves suspensions of gold and carbon nanoparticles in water. A small droplet of the suspension is placed on a glass slide and a low power laser is focused onto a small region within the droplet near its surface. Through a fascinating process involving optical trapping, heating, evaporation, convective fluid flow, and chemical interactions, the nanoparticles fuse near the laser focus and as the experimenter moves the laser focus around in the droplet a continuous filament of the fused material follows. These remarkable structures remain completely intact even after the fluid is drained off. In such a manner “hand-crafted” filaments of up to millimeter lengths and about 10-60 times wider than the original nanoparticles can be formed with arbitrary shape and design. These resulting hierarchical architectures could be useful for a variety of applications including biological sensing, electronics, optics and emerging energy technologies.

LW12620

Superconducting quantum computing leaps ahead

Atoms and molecules jump abruptly between discrete quantum levels when observed. For the first time, we have seen the same phenomenon in a macroscopic electrical circuit – an “artificial atom” — engineered to exhibit quantum behavior. The key to the success of the experiment was the development of a new type of amplifier. Just like a fancy stereo allows one to hear the subtleties of a musical piece, our ultra-low noise amplifier enabled us to see the delicate quantum dance of our “artificial atom”. Both the amplifier and the “artificial atom” were constructed using superconducting circuits made out of aluminum and cooled to a fraction of a degree above absolute zero. The combination of low loss in the superconductor and the extremely low temperatures enabled the electrical circuit to display quantum behavior. This is a major step for solid-state quantum computing as high fidelity measurements of this type are crucial for correcting errors in a quantum computer. Such computers would harness quantum physics to perform calculations and promise to be more powerful than any non-quantum computer that could ever be built.



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BZR1120

Controlling the charge state of nitrogen-vacancy centers

In our recent study, we managed to control and switch the charge state and, consequently, the color of nitrogen-vacancy (NV) centers in diamond. The NV center, which lends its color to some gemstone diamonds, is a lattice defect with an ionization energy within the diamond bandgap. Due to their suitable optical properties, NV centers are promising candidates for qubits and highly sensitive magnetic field sensors. Up to date, most of research has been focused on the naturally more abundant, negatively charged and purple-colored NV- state of these
centers.

We now demonstrated a controlled way to convert these negatively charged centers into their neutral state NV0. To achieve this, we focused on shallow centers which were implanted only few nanometers under the diamond surface. In this region, the Fermi level depends strongly on the surface termination. By terminating the diamond surface with hydrogen, we managed to lower the Fermi level below that off NV-, so that ionization into NV0 became favorable. This result, changing the color of a diamond from purple to yellow, is not only aesthetic, but will also enable a detailed understanding of the neutral change state of NV centers. Furthermore, the controlled alteration of the charge of NV centers described in our work is a crucial step towards the demonstration of the electronic control of the charge state of single NV centers in diamond, and thus opening attractive alternatives for the realization of diamond-based quantum computers.

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LZ12582

Intergalactic alcohol probes drifting constants

In this Letter we propose to use methyl alcohol (CH3OH) for probing the variation of the proton-to-electron mass ratio. Methyl alcohol is one of the simplest molecules that exhibits internal rotation; the methyl (CH3) group rotates with respect to the alcohol (OH) group. In addition, the molecule rotates as a whole. We found that microwave transitions that convert the internal rotation to overall rotation – and vice versa – are very sensitive to the proton-to-electron mass ratio. When the proton-to-electron mass ratio changes by a certain fraction, the resulting fractional frequency change in methyl alcohol is up to 50 times this fraction. This is an order of magnitude larger than the transitions used so far in searches for possible spatial of temporal variations of the proton-to-electron mass ratio.

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LX12353

COULD RELIC GRAVITONS BE LEFT-HANDED?

Could the graviton be more like the neutrino, which is only
present in Nature in a left-handed version? The possibility of
gravitational handedness has long been entertained in Ashtekar's
formulation of quantum gravity. In our Letter we reevaluated the
mechanism producing gravitational waves in the early Universe.
Relic gravitational waves are generated as microscopical vacuum
quantum fluctuations, which are then stretched to cosmological
sizes by a period of accelerated expansion. We found that
Ashtekar's formulation, while predicting equivalent right and left
handed graviton states, leaves a distinctive parity violating mark
in their vacuum fluctuations. At its most extreme it could be that
only right or left handed gravitons are produced in the early
Universe. Such a "chiral'' background of gravitational waves
would have a dramatic observational fingerprint. Current and
upcoming cosmic microwave background experiments focus on its
polarization. It is known that one particular polarization
component can only be produced by gravitational waves. But more
importantly, some polarization measures are non-zero only if, in
addition, the gravitational wave background is chiral. Therefore
the effect reported here could open up the doors of
experimentation to quantum gravity, at long last.



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BZ11478

New Experimental Opportunities for Studying Structure and Atomic Mobility of Melts

A novel electrostatic levitation furnace for neutron scattering experiments on melts has been developed. The electrostatic levitation technique allows processing and melting of both electrically conductive and insulating materials under high vacuum conditions. By this containerless technique even chemically reactive melts can be investigated at high temperatures as well as in the undercooled liquid below the melting temperature. The avoidance of crucible materials in the vicinity of the freely suspended sample (see figure) results in an excellent signal-to-background ratio in scattering experiments. To enable appropriate scattering rates we increased the typical sample volume by one order of magnitude as compared to former generations of electrostatic levitators.

First experiments using the electrostatic levitator allowed us to investigate glass-forming Zr-Ni melts by neutron diffraction and quasielastic neutron scattering in a broad temperature range in the stable melt above the melting point and in the undercooled regime nearly 200 K below the melting temperature, determining structure factors and Ni self-diffusion coefficients. We demonstrate that this new approach results in a significant improvement of the quality of the data and an increased range of accessible temperatures.

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EW10532

Electrical memory in human skin

In this paper electrical conductance in human skin is shown to display some memory of its electrical history. This can only be understood by using a newly realized, yet fundamental, memory element in electrical theory, namely the so-called memristor. Memristors clarify basic electrical circuit theory, complementing resistors, capacitors and coils. We show that the memristor is a good candidate for explaining many very important bioelectrical phenomena that are yet not fully understood. In particular, this holds for transport of ions in capillaries and pores, systems that are very common in living systems as well as in other solid state materials. Such flow of ions is important and a prerequisite for living cells as well as for many other biological processes. In overall, the memristor is shown to open a neglected field in bioelectricity, and hence is expected to be of particular interest in the future.


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LX12388

Giant Gamma-Ray Bubbles are as Old as Galaxy

Recently NASA announced the startling discovery by its orbiting gamma-ray telescope, Fermi, of two enormous gamma-ray emission structures that hang like lightglobes above and below the centre of the Milky Way. These `Fermi bubbles' extend an astounding 30 thousand lightyears from the plane of the Galaxy. Thus far the Bubbles have been understood as illuminated by a mysterious population of youthful and highly energetic electrons. In this astrophysics context, `youthful' means an age of 10 million years or so. Now astrophysicists assert that the Bubbles have been inflated and illuminated by a wind of cosmic ray nuclei and super-hot plasma that has been blowing out of the centre of the Galaxy for almost 10 _billion_ years. This wind is driven by the sustained star-formation that has occurred in the Galactic nucleus since the youth of the Milky Way. In fact, the Bubbles constitute a perfect calorimetric recording of Galactic centre activity over the history of the Galaxy.


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LT12340

Damage to DNA achieved gently, but effectively!

While it has long been established that damage to DNA occurs upon irradiation by energetic gamma rays and x-rays, results of laser-based experiments of DNA plasmids in liquids now reveal that disruption of DNA structure can also be induced by very low-energy electrons and radicals like OH. Exposure of a mixture of DNA and water to ultrashort pulses (lasting only a few tens of femtoseconds) of high-intensity laser light gives rise to the formation of low-energy electrons and OH radicals as water molecules undergo ionization and break-up. The resulting low-energy fragments have been shown to induce nicks in the DNA structure, with the OH radicals being about four times more effective in inducing damage than electrons. These findings may have implications in the use of high-intensity lasers in biomedical applications like laser surgery.

LY12164

Rebuilding a pulse of light in space and time

Multiple light scattering in disordered materials such as paint, paper or biological tissue breaks apart a laser pulse in space and time, a process that appears to be completely irreversible. In this Letter, we demonstrate that the reverse is possible: by spatially structuring broad-band light incident on a scattering medium, we are able to rebuild an intense ultra-short laser pulse from the fragments of the scattered light. The new method to control light in space and time has promising applications in imaging, sensing, and selective destruction inside opaque materials. Moreover, it will greatly enhance control of light when combined with new optical structures such as nanophotonic devices and metamaterials.


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LW11796E

Boiling on the nanometer scale

Interaction of ultra-short laser pulses with solid state is still not completely understood although studied for several decades. According to the commonly-accepted theory, after the pulse is absorbed by the metal surface, the temperature of the latter increases and the metal melts, evaporates, and solidifies again. The remarkable feature of this process is that the temperature increases faster than the liquid metal can start boiling. As the result, a thin layer of superheated liquid metal appears on the surface. In this paper we demonstrate self-organized pattern appearing by explosive boiling of thin films of superheated melts. As the surface temperature decreases below the melting point, the still boiling liquid solidifies and the pattern gets frozen and can be studied afterwards by mean of common experimental tools like electron microscopy. The characteristic length scale of the pattern is in the range of several hundred nanometers and can be easily tuned in the experiments by changing the laser energy. Due to this property the self-organized nanopatterns could be of interest for nanotechnology.

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LU12747 and DX10739

Solution of Cosmology's Biggest Problem Suggests A New View of Time

Did the past happen as we remember it? A new solution to one of
cosmology biggest problems suggests not. For thirteen years, we have
known that the expansion of the Universe is being accelerated by a
mysterious `dark energy’. The simplest explanation of this dark
energy is Einstein’s cosmological constant, Lambda, a form of energy
that fills the vacuum and drives the universe apart. However, there
is a problem with Lambda: it is some 123 orders of magnitude smaller
than we expect it to be. Not only is Lambda very small, but it also
defines a fundamental time scale that is, coincidently, the same
magnitude as the current age of the Universe. This remarkable
coincidence and the smallness of Lambda represent the biggest unsolved
problem in cosmology today: the cosmological constant problem. In
our PRL letter and PRD article we present a new solution to this
problem that avoids small numbers, does not require new and undetected
forms of matter, and which is subject to a high precision test in the
near future. Excitingly, our solution implies an radical new
understanding of time in which our past, and remembrance of it, slowly
changes over time.


***

LY12463

Creasing to Cratering under Voltages

A team of researchers has observed, for the first
time, the creasing to cratering instability in polymers under
electrical voltages. When bread dough is raised in a bowl, the top
surface of the dough may fold upon itself to form creases due to
compressive stresses developed in the dough. Surprisingly, this
phenomenon may be related to failures of electrical polymers that are
widely used in energy-related applications. Subjected to a voltage, a
substrate-bonded polymer film develops a biaxial compressive stress
parallel to the film. When the voltage reaches a critical value, the
compressive stress induces a pattern of creases on the polymer. If the
voltage further rises, the creases strikingly evolve into craters in
the polymer, as the electrical stress pulls the creases open. Polymers
usually breakdown electrically immediately after the creasing
instability, which can cause failures of insulating cables and organic
capacitors. The team innovatively introduces a protective layer
right beneath the polymer film. The protective layer prevents the
electrical breakdown, but allows the team to observe the creasing to
cratering instability for the first time.

***

LY12048

Detecting Vanishing Dimensions Via Primordial Gravitational Wave Astronomy

Lower-dimensionality at higher energies has manifold theoretical advantages
as recently pointed out - it removes the standard model hierarchy problem,
enables much easier quantization of gravity, and allows one to attack the
cosmological constant problem in a completely new way. Moreover, it appears
that experimental evidence may already exists for it - a statistically
significant planar alignment of events with energies higher than TeV has
been observed in some earlier cosmic ray experiments. If the dimensional
cross-over really happens at TeV scale, then one can make definite
predictions for the collider experiments. Finally, gravitational wave
astronomy enables a robust and independent test for this new paradigm. Since
(2+1)-dimensional spacetimes have no gravitational degrees of freedom,
gravity waves cannot be produced in that epoch in the history of the
universe. This places a universal maximum frequency at which primordial
waves can propagate, marked by the transition between dimensions. This
cut-off frequency is accessible to future gravitational wave detectors such
as LISA, which allows for a clear cut falsification or confirmation of this
paradigm.

Largest Physics Meeting of the Year Convenes
Next Month in Dallas, Texas, March 20-25, 2011

Highlights of the American Physical Society (APS) 2011 March Meeting

100th Anniversary of the Discovery of Superconductivity to be Celebrated

The March Meeting of the American Physical Society (APS) –the largest physics meeting of the year -- will take place from March 20 to 25 at the Dallas Convention Center. Approximately 7000 papers will be delivered in the course of the meeting. Journalists are invited to attend the meeting free of charge. Registration information may be found at the end of this press release. Hotel information can be found at the meeting website.

Traditionally the March APS meeting has been a major venue for presenting the scientific principles and techniques behind many of the high-tech devices of today and tomorrow. The large topic areas at the meeting are condensed matter physics, computer physics, biological physics, chemical physics, polymers, and fluids. Specific hot topic areas include graphene, topological insulators---materials that are insulators on the inside but exceptional conductors on the outside---quantum computing, smart materials, bio-engineering, energy efficiency, spintronics, microfluidics, and ultracold atoms.

Not all the presentations at the meeting are highly technical. Session H8 features talks on the physics of rodeo, singing Tesla coils, and the science behind barbecue. Monday, March 21 at 7:45 pm, Vincent Crespi will talk about the attempt to broaden public understanding and appreciation of science, especially nanoscience, through exhibits at museums.

MEETING HIGHLIGHTS

BEAM ME BACKWARDS, SCOTTY
Rather than send airplanes into the upper atmosphere to detect pollutants or biological weapons, researchers at Texas A&M University, with collaborators from Princeton University and the University of Arizona, have developed a backwards-emitting laser-like beam that could be developed to identify gases and particles in the sky. To create the backwards-emitting beam, the team first shoots laser pulses of different speeds to excite air molecules. The two pulses join to generate a new laser-like pulse, called a backwards-emitting beam, that travels back towards the source. This beam could potentially be exploited for new types of remote sensing and may lead to a novel way to measure components of the atmosphere. Because the researchers are able to control where the laser-like beam is created, they could examine the air at nearly any altitude, searching for anthrax spores or pollution particles miles above the Earth without ever having to the leave the ground.

THE TINIEST ANTENNA
Researchers at the Institute of Photonics Sciences (ICFO) in Barcelona who produced the world’s smallest antennas in August of 2010 have now expanded their collection to include a palette of tiny antennas that can transmit photons in various patterns. The antennas operate much like the old fashioned TV antennas that once sprouted from most rooftops, except that they are millions of times smaller and are constructed of nanoscopic rods that direct the light emitted from a quantum dot. Niek van Hulst of ICFO-Barcelona will describe recent advances in nanoantenna development, and will discuss applications ranging from the detection of signals emitted by biological molecules to the construction of efficient connections between quantum dots for quantum computers and highly secure cryptographic systems.


X-RAY VISION FOR ARCHAEOLOGISTS
Archaeologists studying text carved into stone tablets or painted on pottery struggle to read the ancient markings when they have been eroded or obscured over time. To help them out, a trio of physicists at Cornell University created a way to expose traces of ancient markings, using a technique called X-ray fluorescence (XRF) imaging. XRF imaging reveals chemical traces left behind by tools and paints that are invisible to the naked eye. High resolution images can be created from XRF scans in minutes to hours. After starting with ancient Greek and Roman objects, the physicists turned recently to imaging Mayan artifacts. On one piece of Mayan pottery, black paint was partially obscured by a layer of black crud. Using XRF imaging, the researchers revealed the original pattern of paint by identifying and isolating chemicals specific to the paint. The team can do the same to reveal one layer of paint underneath another. Unlike some other techniques, no special sample environment is required for XRF imaging and objects of different sizes, ranging from a small chip to an eight-foot-tall stone tablet, can be imaged. XRF imaging is also non-destructive because it does not require a sample to be removed from an artifact. The technique allows archaeologists to see what the eye cannot, opening the door to future breakthroughs in understanding ancient civilizations.


NANO-SCALE VIEW COULD AID IN EARLY CANCER DETECTION
A recently-developed technique to analyze swabbed samples of cells could provide early lung, colon, ovarian, pancreatic, and esophageal cancer detection. Vadim Backman of Northwestern University will give a talk about an optical technique, called partial wave spectroscopic (PWS) microscopy, that can reveal the cancerous breakdown of cells at the nano-scale level. By zooming in very close, PWS can detect the signature of cancer in the disarray of a single cell’s nucleus. Like detecting a home’s risk of earthquake damage by spying cracks in the brickwork, PWS can detect the onset of cancer from the disorder at the heart of a cell, which occurs long before other outward signs of cancer develop. A recent small-scale trial showed promise for early detection using PWS when lung cancer was detected in cheek swab samples. The method is currently in the clinical research phase.

HOMELAND SPECTROSCOPY
Explosives in airports can be hard to detect but two new creations could make detection easier and airports safer. Abhishek Kumar and colleagues at the University of Massachusetts Lowell created a new fluorescent polymer developed to respond to trace elements of explosives in the air. A thin film of the polymer solution is smeared on a flat surface, like a glass slide, and exposed to the air being tested. By shining a light on the sample and measuring the amount of fluorescent light emitted, it’s possible to quickly determine whether the film has been exposed to even a tiny amount of a chemical bound to the polymer. The creators are currently working to produce a small commercial device with multiple sensors whose redundancy could help reduce false-positives. The polymer can be mass-manufactured and distributed broadly at a low cost, bringing enhanced explosive detection to airports around the world. Srikanth Singamaneni and colleagues at Washington University developed flexible and durable swabs that will enable security officials to use a more sensitive form of spectroscopy, called surface enhanced Raman scattering, to search for traces of explosives in cars, suitcases, and other containers.

NEW TAKES ON PHYSICS AND EDUCATION
Comic books as educational tools? Rebecca Thompson, of the American Physical Society’s Outreach Department, will talk about the use of comic books to teach physics to children. She’ll discuss three APS comic books including the laser-related adventures of a superhero called Spectra and a book about Nikola Tesla’s professional battle with Thomas Edison. John Fanchi from Texas Christian University will present a new undergraduate program intended to motivate students to work on solutions to our energy problems by becoming the next generation of energy professionals. J. Pedro Ochoa, from the Lawrence Berkeley National Laboratory, will give practical advice on overcoming cultural barriers, speaking from his own experience transitioning from Mexico to the United States and to China. Other topics in the session include a look at the nature of discovery and the pleasure of finding things out, (Joshua Borchardt, North Dakota State University), and an overview of a program at the University of Texas College of Natural Sciences that brings freshman into research laboratories, leading to improved retention, higher GPAs and increased graduate school enrollment. (Rosa Elia Cardenas).

SPIDER-MAN FOR REAL
Spider webs are sticky stuff. Understanding how they trap and retain prey even in wet environments could lead to development of more durable adhesives. A spider-inspired, water-resistant adhesive could be used for anything from tougher bandages to underwater sealants. Vasav Sahni and colleagues at the University of Akron have investigated spider adhesive to reveal how the polymer material is both strong and flexible. The researchers met in the dark of the night when their lab was empty and no vibrations from coworkers’ movement could disturb their work. They measured the force needed to stretch tiny glue droplets, each a third the width of a human hair, from the delicate silk fibers of a spider web. The late night experiments were vital because even a mistimed breath could have ruined their efforts. After gaining an understanding of how the spider glue functions, the team was successful in mimicking the glue in the lab.

NEW GRAPHENE DEVICES AND NOBEL PRIZE LECTURE
Graphene was celebrated last year with the award of the Nobel Prize for physics to Andre Geim and Konstantin Novoselov a scant six years after their discovery of the ultra-thin, strong, and electronically versatile material. Many research groups have now made progress towards practical graphene-based devices that could eventually make conventional silicon electronics obsolete. Among the recently-developed graphene devices being announced in session B37 at the 2011 March Meeting are radio frequency transistors, logic inverters, and transparent and flexible field emission devices, to name just a few. Also in session B37, Walt de Heer of the Georgia Institute of Technology will present an invited talk offering a broad overview of graphene based electronics. In addition, 2010 Nobel Laureate Novoselov will be the featured speaker at a special Nobel Prize Session on Wednesday, March 23 at 5:45 PM.

CARBON NANOTUBE “RUBBER” WITHSTANDS RECORD TEMPERATURE RANGE
A new viscoelastic (or rubber-like) material built entirely of carbon nanotubes retains its properties over a record temperature range, from -196 C to 1000 C. (By comparison, silicone rubber only remains stable from -55 C to 300 C.) The key to the material’s extraordinary resilience comes from relying on a network of carbon nanotubes linked into a random mesh, rather than the polymer molecules that make up most conventional elastics. In order to test the carbon nanotube viscoelasticity, the researchers who developed the material at the Technology Research Association for Single Wall Carbon Nanotubes (TASC) and National Institute of Advanced Industrial Science and Technology (AIST) in Japan conducted impact tests that bombarded samples with steel spheres while the material was at various temperature extremes. The resulting indentations were identical whether the material had been dipped in liquid nitrogen or blasted with a butane torch. Although it’s too early to say for sure what sorts of applications could benefit from such a temperature insensitive viscoelasticity, the researchers who developed it speculate that it may come in handy for craft headed to interstellar space, inside high-temperature furnaces, or perhaps as high performance parts in airplanes and other vehicles. Ming Xu of TASC & AIST will discuss the likely mechanisms behind the viscoelastic’s record-setting temperature range as well as describing new methods the group has developed for creating softer, more elastic and stronger versions of the material.


NANOTUBE FABRIC TOUGHER THAN KEVLAR
Yarns and twines made of carbon nanotubes could lead to the toughest textiles ever made, provided methods to spin them into substantial lengths are successful. Tobin Filleter and colleagues at Northwestern University have developed methods to make nanotube twine tougher still by exposing it to electron beams that cause the fibers to form microscopic mechanical bonds known as crosslinks. The crosslinked fibers are as much as ten times stiffer and stronger than non-irradiated fibers. In the same session, Ray Baughman of the University of Texas at Dallas will consider larger-scale issues of forming carbon nanotube yarns into long enough segments to be woven into fabrics for use in superconductors, Li-ion battery materials, and fuel cells, among other applications.


SUPERCONDUCTIVITY CENTENNIAL
The year 2011 marks a century since the discovery of superconductivity. Session B3 will be devoted to the history of the discovery, including notable superconductivity milestones. Session Q3 looks at research opportunities in superconductivity. Dozens of sessions will cover reports of the latest research findings. The Industrial Physics Forum, a meeting-within-the-meeting sponsored jointly by the American Physical Society and the American Institute of Physics, will look at the latest industrial applications of superconductivity (sessions 1A, 1B, A5). Topics in these sessions include the advent of a comprehensive theory of low-temperature superconductivity, the latest superconductivity applications in the areas of medical imaging, the electric grid, electronics, astrophysical detectors, and sensors for tiny magnetic fields.

MODELING THE DECLINE OF RELIGION
The decline of religion in some modern cultures is a trend reflected in census data. About half of all people in the Netherlands, for instance, identify themselves as having no religious affiliation. Now at Northwestern University and the University of Arizona, researchers have developed a simple mathematical model that accurately describes what is going on. Richard Wiener of the University of Arizona will describe how he and his collaborators used historical census data from a number of countries to track the growth of religious non-affiliation and applied techniques from physics research to analyze the competition for adherents between religious and irreligious segments of modern secular societies. Their model predicts that in many modern secular societies, religions will continue to lose members and be driven toward extinction. The model is also applicable to a variety of competitive social systems, the researchers argue, like smokers vs. non-smokers, vegetarians vs. meat-eaters, obese vs. non-obese people, and Mac vs. PC users.

FRONTIERS IN PHYSICS
As part of the Industrial Physics Forum at the 2011 March Meeting, the Frontiers in Physics session D5 will feature five talks on some of the most dynamic topics in physics. Linda Young of Argonne National Laboratory will speak about the Linac Coherent Light Source, the world’s first hard X-ray laser, based at SLAC National Accelerator Laboratory. Some of the laboratory’s first experimental results are about what happens when an atom’s inner electrons are blasted out with X-rays. National Institute of Standards and Technology (NIST) scientist Joseph Stoscio will describe scanning tunneling microscopes (STMs) that operate at low temperatures and high magnetic fields, making them perfect for exploring quantum mechanical phenomena and conduction in graphene. Stanford physicist Shoucheng Zhang will describe potential applications for topological insulators, materials in which electrons flow easily on their surfaces but not though their interiors. Barbara Jacak, a physicist at Stony Brook University and a leader of a detector group at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory will report on the experiment that created the hottest fireballs ever seen on Earth by smashing gold ions together. The coldest place on Earth, arguably, is the center of Deborah Jin’s atom trap at the University of Colorado in Boulder. She will look at the strange chemistry that occurs among atoms at very cold temperatures.


NEW METHODS FOR READING GENES
A faster, cheaper, and more accurate alternative for analyzing DNA may soon be on the market. Shuo Huang and colleagues at Arizona State University have developed a new approach for determining the components that make up individual molecules of DNA using a scanning tunneling microscope to probe along a piece of DNA and read the electronic signature of each of the bases in a DNA string. The researchers predict that it will eventually be a faster, cheaper, and more accurate alternative to existing methods for sequencing single pieces of DNA, though it is currently limited to reading pieces no longer than 10 bases long. To be commercially viable, the researchers believe that the technique should be able to read DNA segments made up of 1,000 bases or more. They are currently developing a version of the device that they hope will lead to the next generation of rapid and cheap DNA analysis.

TOPOLOGICAL INSULATORS
Topological insulators, materials that allow charge to flow easily on their surfaces but not their interiors, are the one of the fastest-growing subjects of physics research. The insulators are expected to be a boon for the development of spintronics -- circuitry that exploits the spin of electrons as well as their electrical charge. Topological insulators are featured in many sessions including D2, H2, Y2, A35, B35, D35, H35, J35, P35, and others. Some specific new results: Nuh Gedik and his colleagues at MIT will report (papers J35.00008, J35.00010, J35.00012) on the use of light to probe the electron currents, some of them on the surface of the material and some of them perhaps traveling through a buried structure beneath the surface. Kesong Yang (X32.00005) will announce the discovery of some 40 new topological insulating materials.


HIGH-PURITY GERMANIUM CRYSTALS FOR DARK MATTER EXPERIMENTS
More than 80% of the matter in the universe is a mystery to science. We call it dark matter, and though we know it exists, we don't know what it is and we have never been able to detect it directly. A number of new experiments to detect dark matter are underway in Japan, Europe, Canada, and the United States. These experiments are being conducted deep underground, hidden from the interfering radiation produced by cosmic ray showers. Dongming Mei from the University of South Dakota will describe the latest results in preparation of high-purity germanium crystals for the proposed experiments for the Deep Underground Science and Engineering Laboratory (DUSEL). The laboratory is being constructed more than a mile underground in the former Homestake gold mine in Lead, S.D. Mei and his colleagues are studying how to grow large crystals of high-purity germanium up to a few kg in weight in the underground environment at DUSEL in order to detect dark matter and to study neutrinos. Once in place about two years from now, the crystals will be used to detect particles of dark matter, as well as other rare and exotic phenomena. Mei will also present techniques for identifying impurity levels that can degrade the crystals’ performance.

SELF-PROPELLED MINI MACHINES
Rachita Sharma and colleagues at North Carolina State University have developed a technique for remotely steering millimeter-sized machines that are self-propelling when placed in a fluctuating electric field. Like miniature boats, the tiny machines float on water and pump microscopic amounts of fluid across their surface when the electric field is turned on, which propels them forward. Changing the field can make the minuscule machines turn or reverse course. The group is also working on self-propelled particles based on living cells that rely on glucose for power. Such devices may one day precisely deliver drugs in the body, diagnose medical conditions, and detect toxins in the environment, among other applications. Videos of the devices in action are available.

PROTEIN FOLDING SPEED LIMIT
One of the most fundamental problems in modern biophysics is that of protein folding -- how the genetically-defined sequence of a protein completely determines its three-dimensional structure. Milo Lin and colleagues at the California Institute of Technology have determined the speed limit of protein folding by measuring and modeling one of the simplest shortest steps in the process -- the initial formation of a common protein structure called an alpha helix. They modeled this protein component as a collection of connected spheres. They also experimentally observed the same folding process by making a tiny protein of five amino acids and tracking the folding over the course of a few nanoseconds. Comparing the model and experiment allowed them to identify the factors that limit folding speed.

RURAL STOCK EXCHANGES AND PLANETARY-SCALE TRADING
Physicists in Boston are exploring the wisdom of decentralizing stock exchanges. Alexander Wissner-Gross, of MIT and Harvard University, and colleagues analyzed the advantage of coordinating financial transactions from centralized locations, asking whether it would be advantageous to decentralize exchanges, and if so, where the exchanges should be located. Their idea, first presented last year in the journal Physical Review E, is that putting an intermediate trading center between two major centers is advantageous if the trading is rapid and auditable. They found that there is always an optimal trading position located between any two points on the Earth, with some in rural areas. They worked out a formula for calculating where the locations could be. At the 2011 March Meeting, they will present detailed results that examine what happens when there are multiple intermediate trading points located between major centers of commerce. They have worked out some of the most profitable locations on Earth from which to coordinate trading. Rather than consolidate trading at places like the New York Stock Exchange, the analysis calls for treating the planet itself as one giant trading floor -- something they are now speaking to a number of companies about doing.

THE PHYSICS OF ECONOMIC DIVERSITY
Combining statistical physics and economic development theory, physicist Cesar A. Hidalgo of MIT's Media Lab along with Ricard Hausmann, the director of the Center for International Development at Harvard University and former chief economist of the Inter-American Development Bank, has modeled economic data from countries around the world to predict future economic production. There is a predictable aspect to the global economy, Hidalgo said, but the processes operate over periods of 10-15 years, which is much longer than the time scales of political cycles. They found a set of universal rules that create robust economic patterns seen across the globe. The ability of a country to produce a new product in the future, for instance, is highly dependent on the specific mix of products the country currently produces. This makes predicting a country's future industries possible. Moreover, economic diversity itself tends to be "contagious," crossing borders from one country to the next. Countries are 50 percent more likely to begin exporting a new product if a neighboring country is already exporting that product. The work has raised the interest of the World Bank and the United Nations Development Programme. The researchers claim that the rise of China over the last decade and the crash of Greece in the last few years would have been predictable using their model because of the economic diversity of those two countries in the 1990s. Looking forward for the next two decades, they predict that Turkey, Indonesia, and Vietnam should all see stellar growth. They believe Russia, however, will experience more modest and volatile growth.

PHYSICS HISTORY/INTERNATIONAL PHYSICS
Session V24, History of Physics and International Programs, covers a spectrum of historical topics, including an effort just after World War II to control the spread of nuclear weapons, the 1946 Acheson-Lilienthal Report on the International Control of Atomic Energy, the wealth of radio research that originated in wartime radar work at MIT, Willie Hobbs Moore (1934-1994) -- the first female African-American physicist, physics research in sub-Saharan Africa, and talks about research in Finland, Latin America, and East Asia. Session X8, Migrations of Physicists, is about the movement of physicists across international borders. The topics include a look at the International Centre for Theoretical Physics in Trieste, Italy, the forced migration of scientists under the Nazis, the migration of scientists from Central Europe during the Cold War, the migration of German scientists into Russia in the 18th and 19th centuries as well as the emigration of scientists from Russia during the Soviet and post-Soviet eras, and the complex migration patterns of Chinese physicists in America--some of whom stay in the U.S. while others return.

A LIST OF OTHER INTERESTING TALKS BY DAY

MONDAY, MARCH 21

--Gauging a physicist’s success, beyond citation counting
--How do neurons grow?
--A look at Kamerlingh Onnes’ discovery of superconductivity in 1911
--A large quilt, measuring 84 x 84 inches, will be used to illustrate the quantum states of graphene
--Using a quantum dot as a beam splitter for Cooper pairs of electrons as a source of entangled particles
--Qubits in a semiconducting nanowire
--A new approach for high-efficiency water desalination
--New materials that can address the challenges of lithium-ion batteries for energy storage
--Applications of Statistical and Nonlinear Physics to Social Systems
--Bionanotechnology

TUESDAY, MARCH 22
--Fingerless robotic hand
--Clay bubbles and the origin of cellular life
--Quantum magnetic analog of forest fires
--Supercurrents flowing in ferromagnets
--Computational physics’ greatest hits
--The first real single-molecule transistor
--Drowning in Carbon: The Imperative of Nuclear Power
--The physics of cancer
--Financial, social, co-evolving and interdependent networks


WEDNESDAY, MARCH 23
--Electronic properties of graphene change depending on how many layers are stacked up, including effects of twisting one layer relative to another
--Observation of a box-shaped shock wave during the collision of two clouds of fermion atoms
--The physics of evolution
--Theoretical physics in industrials settings: the auto industry, high-tech sector, oil and gas industries


THURSDAY, MARCH 24
--The smallest ever loops of high-temp superconducting films, part of a surface patterned with loops and nanowires, for the purpose of making electronic devices
--Only cryostat where one can directly view a 1-K surface through a room-temperature window http://meetings.aps.org/Meeting/MAR11/Event/143421
--Pressure-assisted ejection of DNA from bacteriophage
--Compressed air or vacuum for moving automobiles and trains

FRIDAY, MARCH 25
--Silicene nanoribbons, silicon analogues of graphene
--Highest electric field strength, 2 x 10^9 V/m, in a plate capacitor gap
--Crystal growth dynamics


************************************************
MORE INFORMATION FOR JOURNALISTS
- General Meeting Information
- Searchable Abstracts

PRESS CONFERENCES
Press conferences will be held daily in the Dallas Convention Center rooms A125/136. A press conference schedule, which will include instructions for dialing in remotely, will be issued in early March.

REGISTERING AS A JOURNALIST
Journalists planning to attend the meeting should contact James Riordon about free registration (riordon@aps.org, 301-209-3238).

PRESSROOM INFORMATION
A dedicated and staffed pressroom will operate throughout the meeting at the Dallas Convention Center. Phones, computers, printers, and free wireless Internet access will be available to reporters using the pressroom.
- Location: Dallas Convention Center, rooms A118/119; press conferences in A125/136
- Hours: MON-THU, 7:30 a.m. to 5:30 p.m. and FRI, 7:30 a.m. to noon
- Phone numbers: 214-853-8001, 214-853-8002, 214-853-8003, 214-853-8004
- Fax number: 214-853-8000
- Food service: Both breakfast and lunch will be provided on MON, TUE, and WED. Breakfast only will be served on THU, and coffee/tea will be available on FRI.

LX12399/Phys. Rev. Lett. 106, 053602 (2011)


Physicists make “sunglasses for atoms” using bizarre quantum effect

Researchers in Barcelona have developed a new, extremely selective
optical filter to protect atomic quantum memories, part of a proposed
quantum Internet, using one of the most paradoxical effects in quantum
physics. In the quantum network, particles of light (photons) would be
sent between distant locations, and stored in quantum memories
(collections of atoms), when they are not in use.

We all know the effect of sunglasses: Sunglasses block dangerous,
invisible UV light in order to protect our eyes, while they let pass
most of the visible light. In principle, this kind of filter could be
used to feed quantum memories the very specific color they can store
while protecting them from light that has not the right color. To have
an idea of the kind of selection we are talking about: Of the light
visible to the human eye, less than one millionth can be stored in an
atomic quantum memory. But there is a problem: it is hard to find a
filter that transmits only this extremely specific color and blocks
all the rest. However, it is easy to find a filter that absorbs a very
specific color.

To solve this problem, researchers led by Prof. Morgan Mitchell at
ICFO have used a paradoxical quantum effect known as “Interaction-Free
Measurement” or IFM. First predicted in the 1990s, IFM uses quantum
interference, in which a particle takes two paths at the same time, to
do something that would seem impossible: IFM can turn transmission
into absorption and vice versa. Through IFM, a collection of atoms can
therefore be made to transmit a specific color, instead of absorbing
it. The researchers took advantage of this and put the same atoms that
are used in a quantum memory into an IFM to implement a filter at the
wavelength at which the atoms are normally absorbing.

The researchers used these “sunglasses for atoms” - that select 1 part
out of 5 million of the visible spectrum - to create pure single
photons of an extremely well-defined color for the first time. These
filtered photons have all requirements that are essential in an
advanced quantum network.


***

LW12091

Why bubbles don’t stick to walls

The next time you watch the bubbles glide elegantly up the side of your champagne glass, consider that you are in fact observing the result of a fundamental physical force, predicted by H. C. Hamaker in 1937, but only now conclusively demonstrated.

The Van der Waals force acts between all bodies, and is almost always attractive, often responsible for strong adhesion, such as the feet of geckos. However, for certain combinations of materials, the force can be a repulsion, which is very strong at small separations. It is possible that in the future it could be used to levitate objects and make devices which are experience no friction.

This work uses a tiny bubble as a probe to measure these forces. The bubble is repelled by solid surfaces in water, and in order to measure such small forces precisely, an Atomic Force Microscope is used. This device measures the movement of a tiny lever the size of a human hair to measure small forces very accurately.

It is found that, as predicted by theory, the strength of the force can be controlled by the material of which the surface is composed, with gold setting the standard for the biggest repulsion.

These results not only demonstrate the presence and magnitude of this unusual force for the first time, but also suggest that we may be able to design micro-scale devices for handling fluids with no friction

LS12815E

Reconsidering the Human Genome Structure

The human genome presents compositional features of many different scales and complex long-range correlations. This suggests that compositional fluctuations are scale-invariant, and therefore that there is not a typical dominant scale of genome organization in many orders of magnitude, typically up to orders of 100 kb. At this
scale, it is well-known the existence of isochores, i.e. long DNA tracks of relatively homogeneous G+C content with a typical size of 100 kb. To date, human genome is viewed as a mosaic of isochores harboring the rest of genomic elements. However, first we present evidences showing that isochores are actually organized at much larger scales into gigantic compositional segments or superstructures, with typical sizes of the order of 10 Mb, thus challenging the current view of the human
genome. Second, we introduce a new segmentation algorithm based on rigorous statistical criteria which takes into account the long-range correlations present in
human DNA, and which is able to detect automatically these superstructures: each human chromosome is divided into a few huge segments (15-20 Mb) with homogeneous G+C content. And third, we show that gene pairs embedded in each superstructure, despite that on average they can be very distant , share many functional properties in common (even more than genes contained in the same isochore, one hundred times closer on average). This suggests the existence of a previously unreported very large scale functional organization of the human genome.

***

LW12551

Attosecond control of photoelectron emission

Since the early days of atomic and molecular physics, it is known that
the natural time scale of electron motion in atoms and molecules is
the attosecond -- that is a billionth of a billionth of a second. In
the last ten years, with the advent of controllable sources of
ultrashort light pulses, the attosecond scale has become the finest
time resolution reachable in experiments. It is now possible to
observe electrons as they move that fast, in real time. In this
Letter, we demonstrate how the dynamics of an electron ejected from a
molecule, upon absorption of two photons, can be traced with
attosecond resolution using a technique designed so far to
characterize attosecond light pulses. Furthermore, we show how
electron ejection can be controlled and delayed by several
femtoseconds, marking a new step toward attosecond control of chemical
reactions at the electronic level.

LR12245

Chain reaction explosions in vibrated granular matter

One of the characteristic properties of granular materials--e.g.
sand--is that energy is dissipated at collisions so a continuous
energy input is necessary to keep these materials in motion. In this
paper, we show that granular materials can store energy and release it in
the form of energy bursts--like explosions--to the rest of the system
in a chain reaction manner.
This phenomenon that takes place in vibrated mixtures of heavy and
light grains, confined between two close and parallel plates, has been
observed in experiments and simulations. The analysis shows that the
heavy grains store energy in a rapid synchronized vertical motion that
randomly loses its coherence liberating the energy to the whole
system. In the picture, an energy burst sequence taking place in the
cluster of heavy grains (blue) as seen in the simulations (top) and
experiments (bottom).

***

LZ12501

First atom circuit with a tunable weak link

We have created a long-lived (≈ 40 s) persistent current in a toroidal Bose-Einstein condensate held in an all-optical trap. A repulsive optical barrier across one side of the torus creates a tunable weak link in the condensate circuit, which can affect the current around the loop. Super flow stops abruptly at a barrier strength such that the local flow velocity at the barrier exceeds a critical velocity. The measured critical velocity is consistent with dissipation due to the creation of vortex-antivortex pairs. This system is the first realization of an elementary closed-loop atom circuit.

Quantum fluids can exhibit properties such as long range coherence and superfluidity that make them useful for constructing sensors and other devices. For example, superconducting quantum interference devices (SQUIDs)are sensitive magnetic field detectors, and superfluid He circuits have been used to detect rotation. Ultracold atomic-gas analogs of electronic devices and circuits,
or “atomtronics” have been proposed including diodes and transistors. Of particular interest is the realization of an atomic-gas SQUID analog. SQUID circuits
have been realized with either tunnel or weak link junctions. In atomic Bose-Einstein condensates, Josephson junctions have been demonstrated only between
adjacent wells. Here we present the first implementation of a non-trivial, closed-loop atom circuit, and show that it is possible to control the current at the
single-quantum level by changing the strength of a weak link. This is an essential step toward realizing an atomic SQUID analog.

Phys. Rev. E 83, 017101 (2011)

Universal patterns in sound amplitudes of songs and music genres

We report a statistical analysis of more than eight thousand songs. Specifically, we investigated the probability
distribution of the normalized sound amplitudes. Our findings suggest a universal form of distribution that agrees
well with a one-parameter stretched Gaussian. We also argue that this parameter can give information on music
complexity, and consequently it helps classify songs as well as music genres. Additionally, we present statistical
evidence that correlation aspects of the songs are directly related to the non-Gaussian nature of their sound
amplitude distributions.


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LQ12585

Emergence and Decline of Scientific Paradigms

Scientific paradigms have a tendency to rise fast and decline slowly. This asymmetry reflects the difficulty in developing a truly original idea, compared to the ease at which a concept can be eroded by numerous modifications. Here we formulate a model for the emergence and spread of ideas which deals with this asymmetry by constraining the ability of agents to return to already abandoned concepts. The model exhibits a fairly regular pattern of global paradigm shifts, where older paradigms are eroded and subsequently replaced by new ones. The model sets the theme for a new class of pattern formation models, where local dynamics breaks the detailed balance in a way that prevents old states from defending themselves against new nucleating or invading states. The model allows for frozen events in terms of the coexistence of multiple metastable states.

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LW12017

MISSING INFORMATION LOCATED EXPERIMENTALLY

There are many physical processes in nature which lead to apparent loss of
information. In the present paper, for the first time, we have
experimentally located the missing information and demonstrated the
validity of quantum no-hiding theorem. To test this we have considered
randomization of a qubit as a prime example of the bleaching process and
reconstructed the missing information from the simplest possible
environment which in our case is a two-qubit system. In the quantum world
if a system interacts with the environment it looses the purity and even
it might end up being in a completely mixed (unpolarized) state that has
no information about the original. Then one may wonder where is the
missing information. The no-hiding theorem is a fundamental result in
quantum information theory which addresses this issue precisely. To put
it simply, the theorem tells us that if any physical process leads to loss
of quantum information, then it must be found in the rest of the
environment with no information being hidden in the correlations. The
result can be applied to many physical scenarios starting from quantum
state randomization, thermalization, decoherence, quantum teleportation,
black hole evaporation and many more. Furthermore, the no-hiding theorem
generalizes the Landauer erasure principle where an arbitrary quantum
state transforms to a fixed mixed state. Indeed, this will have wide
impact whenever one encounters the issue of information loss. The
no-hiding theorem also demonstrates the notion of conservation of quantum
information. Since this is universally valid in quantum world we believe
that its experimental test constitutes an important step.

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LZ12219

Rotate the multiferroic blues away

For decades, researchers have looked for multiferroic materials in which the
magnetization could be controlled with an electric field. But finding a
material with the right combination of properties for practical applications
- a large polarization and a strong polarization-magnetization coupling -
has proven a difficult challenge. In our Letter, we identify a class of
multiferroics in which combinations of certain atomic displacement patterns
- octahedral rotation distortions - give rise to both a large polarization
and ferromagnetism. This result is remarkable because octahedral rotations
usually cannot individually produce a polarization. Most importantly, the
rotations are coupled to the magnetization in such a way that when an
electric field is used to change the direction of the polarization, the
magnetization also changes direction. This is precisely the type of
electric-field controllable magnetic material that scientists have long
searched for. Our work opens a new direction for the discovery of these
technologically important materials.

AX10557

ULTRALONG-RANGE CASIMIR FORCE CAN MAKE OBJECTS FLY

The elusive Casimir effect is one of the most intriguing physical
phenomena, which, due to the quantum fluctuations of the electromagnetic
field, results in the attraction or repulsion of uncharged bodies. This
tiny force is only relevant in the nanoscale, since it invariably decays
with the fourth power of the distance between the bodies. Or at least,
that was thought to be the case until some time ago. Indeed, recently it
was suggested that by guiding the quantum fluctuations of the
electromagnetic field with an array of metallic nanorods it is possible
to boost the strength of the Casimir force by several orders of
magnitude. Here, we demonstrate how this ultra-long range force can be
put into work and used to levitate objects! We show that the plane at
which the nanorods are cut acts as a mirror for the waves propagating
inside the nanorods crystal. However, unlike the usual metallic mirrors,
the wave reflected at the tips of the nanorods is in phase with the
impinging wave. Such a crucial property results in a repulsive Casimir
force that pushes conducting bodies embedded into the nanorods crystal
away from the mirror. This purely quantum force may be strong enough to
act against the gravity and lift up metallic pieces. For example, we
show that a 200 nm-thick tungsten film can be lift up to 1 micron within
a crystal composed of silver nanorods of 40 nm in diameter.


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LY12700

A NEUTRON STAR TURNING SUPERFLUID

Ten years of Chandra observations of the neutron star "Cas A" have revealed
that it is cooling rapidly, an unusual behavior never observed previously.
We present a natural explanation based on neutron superfluidity and proton
superconductivity. These quantum phenomena set in when the temperature drops below some critical value. We propose that neutrons inside Cas A are presently developing a superfluid phase and emitting copius amounts of neutrinos which are cooling the star. Cas A has an age of 330 yrs and no other neutron star is known that is young enough to observe the onset of superfluidity. From Cas A's age, we deduce the neutron p-wave superfluid critical temperature to be a half billion degrees. Furthermore, the combination of the star's high surface temperature, about 2 million degrees, and large cooling rate implies that protons are in an s-wave superconducting state.

The transition to superconductivity has a larger critical temperature because it occurred prior to now when the star's core was warmer. This is the first direct evidence that these phenomena, predicted by theoretical models of high energy-density matter, occur within neutron stars.


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AY10627

Propagation of relativistic charged particles in ultracold atomic gases with Bose-Einstein condensates

At the present moment the Bose-condensation phenomenon in gases of atoms
and molecules is experimentally realized in extreme physical conditions
(ultralow temperatures). A Bose-Einstein condensate (BEC) is a coherent
state of matter, i.e., the state with practically identical behaviour of
particles that form it. The consequence of the external extreme conditions
and coherent behaviour is the manifestation of different phenomena that
are difficult or impossible to observe in other conditions.

To the vivid effects related to the BEC phase one should also add some
peculiarities of a propagation of the relativistic charged particles
through a condensed gas. Most probably, this sort of problem is considered
for the first time in the framework of the present paper. The main
attention was paid to the energy change of the propagating particles. This
change results from the Cherenkov effect in the gas with a BEC. The most
uncommon result of the consideration is that at the certain conditions the
particle not only emits the energy, but it also can be accelerated by the
ulltracold gas. We define the conditions for the particle acceleration and
discuss also the possibility of defining the spectral characteristics of
atoms forming BEC by registering the Cherenkov radiation.


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BW11359

Revealing the Carrier density and mobility of the Graphene layers in Graphite

Using an experimentally simple method to obtain the mean free path and density of electrical carriers of the graphene layers inside a thin graphite flake without adjustable parameters, a team from Germany and Spain demonstrated that these carriers can move several micrometers without having scattering whereas their density remains extremely small and all at room temperature. The obtained values overwhelm by orders of magnitude those obtained in single graphene layers of micrometer size revealing that ballistic electronics in graphite is feasible. From the basic research point of view, the results cast now strong doubts on the validity of the commonly used electronic band structure of graphite assuming values for the carrier density that appear to be non-intrinsic of the ideal graphite structure. The figure shows scanning electron microscope pictures of two samples showing the constrictions used to restrict the flow of the carriers and obtain directly their mean free path through the measurement of the electrical resistance.



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EY10601

Non-classical transport in anisotropic fractal media

Numerous observations show that impurity transport in geologic media, as a rule, is not described by the classical diffusion laws, according to which the mean-square displacement of the particles grows linearly with time. Instead the transport process occurs in the regime of super-diffusion when mean-square displacement grows proportionally to the time in a power greater than unity, or sub-diffusion with the time exponent less than unity. A fractal geometry of fractures leading to long-range correlations of infiltrating moisture velocities may be the physical background of super-diffusion. Researchers have now shown that the presence of anisotropy and directedness of moisture infiltration due to the gravity lead to a number of interesting peculiarities in the impurity transport phenomena in fractal media. Among them are anomalous drift and coexistence of super-diffusive regime in vertical direction and classical diffusion in horizontal plane. In the case of strong anisotropy a considerable contraction of concentration distribution occurs in horizontal plane at large vertical distances. The peculiarities stated above are important for the safety problem of radioactive waste disposal in geologic media.

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LX12087

Theory of Everything Finding a Way to Describe Life

String theory is said to be the theory of everything. But
until now its realm has been very far away from the life of ordinary
people. Not so anymore, as a group of theoretical physicists at
Uppsala University in Sweden and CNRS in France argue that
amazingly string theory describes even life itself. For this
they develop a string theory depiction of proteins, the workhorses
of all living cells. In order that life as we know it can take place,
proteins in our cells must each become folded into their own, very
specific shape. If misfolded, a protein can not fulfill its mission.
This can lead to a death of cell or cause tormenting diseases
such as Alzmeimer's, Parkinson's and many cancers. By applying
sophisticated string theory techniques originally introduced to explain
properties of elementary particles like the all-elusive Higgs boson,
and using ordinary personal computers they describe folded proteins
reaching accuracies that occasionally exceed even the most precise
experimental measurements. This can pave a way to a deeper understanding
why and how proteins fold, which in turn may eventually lead to cures
to some of the most unrelenting diseases.