bluuebunny/crossref_metadata_2025 huggingface dataset:
Canada Catalyzes Research and Recruitment
Authors: Feder Toni
Published: March 2007

Aggressive spending in Canada has spruced up research labs and promises an expansion of the Sudbury Neutrino Observatory, but it has also led to a time lag between setting up new equipment and finding money to maintain it.
Special Report: War, Terrorism, and National Security Shape Bush R&D Budget in FY 2004; Civilian R&D Funding Flat
Authors: Dawson Jim , Guinnessy Paul
Published: March 2007

Nondefense physical sciences run a distant second to big increases in weapons development and homeland security in the administration’s budget, and Congress is wondering what happened to money it authorized for NSF.
Molecular Electronics
Authors: Heath James R. , Ratner Mark A.
Published: March 2007

Improvements in our understanding of how molecules transport charge, and how they interface to the macroscopic world, are fueling new devices and applications.
Middle-School Texts Don’t Make the Grade
Authors: Hubisz John
Published: March 2007

Thousands of teachers are saddled with error-filled physical science textbooks that fail to present what science is all about. Physicists deserve some of the blame.
Hydrogen Adsorbed on Silicon Carbide Creates Metallic Surface States
Authors: Wilson Mark
Published: March 2007

Researchers expected adsorption to eliminate surface electronic states. Instead, it created one-dimensional states that resemble nanowires.
The Force Need Not Be With You: Curvature Begets Motion
Authors: Blau Steven K.
Published: March 2007

Cyclic deformations can alter the free-fall motion of a composite body as it moves through curved spacetime.
Supercooled and Glassy Water
Authors: Debenedetti Pablo G. , Stanley H. Eugene
Published: March 2007

Cold, noncrystalline states play an important role in understanding the physics of liquid water. From recent experimental and theoretical investigations, a coherent interpretation of water’s properties is beginning to emerge.
Plasma Accelerators at the Energy Frontier and on Tabletops
Authors: Joshi Chandrashekhar , Katsouleas Thomas
Published: March 2007

Charged particles surfing on electron density waves in plasmas can experience enormous accelerating gradients.
Stretchable Conductors Help Clear the Path to Skinlike Large-Area Devices
Authors: Day Charles
Published: March 2007

Conducting stripes of gold foil can be stretched significantly when they’re stuck to a rubbery substrate.
Government Scientists Do Stints in Embassies
Authors: Feder Toni
Published: March 2007

A fast-growing new program aimed at fortifying science in the State Department is proving to be a hit with participating scientists, and with their home agencies and host embassies.
Four Experiments Give Evidence of an Exotic Baryon With Five Quarks
Authors: Schwarzschild Bertram
Published: March 2007

It’s been a long-standing puzzle that the quantum numbers of all the known mesons and baryons could be attributed to bound states of two or three quarks. But now the first exception has apparently been found.
APS Study Points to Severe Limits on Boost-Phase Missile Defense
Authors: Dawson Jim
Published: March 2007

A two-year study challenges many of the assumptions behind the Bush administration’s $600 million boost-phase program.
HERA Scientists Fight to Extend Strong Interaction Studies
Authors: Feder Toni
Published: March 2007

When should a productive machine be turned off?
Ultracold Fermionic Atoms Team up as Molecules: Can They Form Cooper Pairs as Well?
Authors: Levi Barbara Goss
Published: March 2007

The behavior of strongly interacting degenerate Fermi gases may hold clues to the universal behavior of many-body systems.
Nanoparticles Locate and Flag the Blood Vessels That Nourish Tumors
Authors: Day Charles
Published: March 2007

Ligand-coated droplets of oil can travel through the bloodstream to attach themselves to malignant cells.
Academies Seek to Promote Scientific Excellence in Developing Countries
Authors: Guinnessy Paul
Published: March 2007

With some international guidance, African and Middle Eastern scientists are learning how to influence government policy.
Benjamin Franklin, Civic Scientist
Authors: Lane Neal
Published: March 2007

That early American prototype of a civic scientist would probably address many of today’s concerns with wisdom, practicality, and a deep sense of civic responsibility.
The Contentious Role of a National Observatory
Authors: McCray W. Patrick
Published: March 2007

For 50 years, astronomers have debated, Should large optical telescopes be under the auspices of national centers, or should access to them be controlled by a “benevolent dictatorship of the elite?”
An Optical Probe Can Map Quantum Dot Wavefunctions
Authors: Fitzgerald Richard
Published: March 2007

Near-field optical microscopy, with its subwavelength resolution, provides a new look at nanostructures’ electronic states.
Managing Science at the CIA
Authors: Guinnessy Paul
Published: March 2007

Donald Kerr has been involved in many scientific endeavours—from studying plasma physics to managing a network of forensics laboratories. Now, he faces the daily challenge of keeping the Central Intelligence Agency’s technology one step ahead of the US’s adversaries.
Two Investigators of Pores in Cell Membranes Win Nobel Chemistry Prize
Authors: Day Charles
Published: March 2007

Thanks to the pair’s work, an atom-level picture has emerged of how water molecules and potassium ions pass into and out of cells.
The Green of Green Functions
Authors: Challis Lawrie
Published: March 2007

In 1828, an English miller from Nottingham published a mathematical essay that generated little response. George Green’s analysis, however, has since found applications in areas ranging from classical electrostatics to modern quantum field theory.
New Experiments Set the Scale for the Onset of Turbulence in Pipe Flow
Authors: Fitzgerald Richard
Published: March 2007

Measurements of the stability of laminar flow bring us closer to answering one of the biggest outstanding questions in fluid mechanics.
Sea-Level Rise Exacerbates Coastal Erosion
Authors: Day Charles
Published: March 2007

A recent analysis of more than a century’s worth of data forebodes severe losses of coastal land.
Family Lines Sketched in the Portrait of Lev Landau
Authors: Ryndina Ella
Published: March 2007

Arguably the greatest Soviet theoretical physicist of the 20th century, Landau is intimately seen through the eyes of his loving niece in these excerpts from her memoir.
Fermionic Atoms Appear to Pair Up Much as Electrons Do in a Superconductor
Authors: Levi Barbara Goss
Published: March 2007

A new experiment reports pair formation when a gas of ultracold potassium-40 atoms is in the largely unexplored region of strong interactions.
Acoustics Experiment Shows Why It’s So Hard to Make Out the Heroine’s Words at the Opera
Authors: Schwarzschild Bertram
Published: March 2007

Vocal-tract resonances enhance the output of the vocal cords. They also create the distinctions between different vowels sounds. For sopranos singing high notes, the two functions come into conflict.
French Scientists Take to the Streets to Save Research
Authors: Feder Toni
Published: March 2007

Researchers in France have quit the administrative parts of their jobs to show the government and the public the seriousness of their concerns about the country’s research enterprise and universities.
Special Issue: Origin of Terrestrial Planets and the Earth–Moon System
Authors: Canup Robin M.
Published: March 2007

Increasingly sophisticated computer simulations show how the four solid planets could have emerged through collisions and accretion. One late, giant collision with Earth is the likely origin of the Moon.
Special Issue: Probing the Giant Planets
Authors: Guillot Tristan
Published: March 2007

More than a hundred extrasolar giant planets have been discovered in the past few years. To understand how they were formed, we must study in detail the giants closest to us: Jupiter and Saturn.
Special Issue: Water on Mars
Authors: Jakosky Bruce M. , Mellon Michael T.
Published: March 2007

Mars is cold enough that its meager water content appears to exist today simply in frozen and gas phases. But as recent evidence suggests, that may not have always been the case.
Conflicting Results on a Long-Lived Nuclear Isomer of Hafnium Have Wider Implications
Authors: Schwarzschild Bertram
Published: March 2007

The Pentagon is touting prospects, based on hotly disputed experiments, for a novel class of weapons intermediate between chemical high explosives and fission weapons
Smoke From Burning Vegetation Changes the Coverage and Behavior of Clouds
Authors: Day Charles
Published: March 2007

Aerosols, such as smoke, help clouds to form by acting as nucleation sites for water droplets. But that’s not the only way aerosols influence clouds
High-Redshift Supernovae Reveal an Epoch When Cosmic Expansion Was Slowing Down
Authors: Schwarzschild Bertram
Published: March 2007

The Hubble Space Telescope has provided a harvest of supernovae that exploded when the universe was less than half its present linear size.
Is Sedna’s Strange Orbit the Shape of Things to Come?
Authors: Blau Steven K.
Published: March 2007

A newly discovered distant minor planet may provide clues about the Sun’s early environment.
Lampreys Rely on a Molecular Switch to Detect UV Light
Authors: Day Charles
Published: March 2007

By applying a combination of biochemical and biophysical techniques, researchers have identified a UV-sensitive photoreceptor in the pineal gland of the Japanese river lamprey.
Colwell Reflects on Six Years at NSF Helm
Authors: Dawson Jim
Published: March 2007

Colwell is proud of her accomplishments and passionate about her science, and she has a friendly relationship with both Republicans and Democrats.
Scholars Probe Nanotechnology’s Promise and Its Potential Problems
Authors: Feder Toni
Published: March 2007

With a revolution in everything from toys to tumors on the horizon, scientists in the nanotechnology arena are working to gain the public’s trust.
A Conversation About Solid-State Physics
Authors: Bethe Hans A. , Mermin N. David
Published: March 2007

Hans Bethe reminisces about the first applications of quantum mechanics to the theory of solids in the late 1920s and early 1930s.
Lovely as a Tree Amplitude: Hidden Structures Underlie Feynman Diagrams
Authors: Blau Steven K.
Published: March 2007

String theory, Fourier-conjugate spinors, and quantum chromodynamics are linked in ways that suggest new methods to compute probability amplitudes for high-energy particle interactions.
A Dark-Horse Entry in the Race for an Excitonic Condensate
Authors: Levi Barbara Goss
Published: March 2007

Evidence for a superfluid made of electron-hole pairs comes, surprisingly, from quantum Hall systems.
Dusty Plasmas in the Laboratory, Industry, and Space
Authors: Merlino Robert L. , Goree John A.
Published: March 2007

Charged microparticles are an annoyance in the plasmas of fusion energy schemes and semiconductor manufacturing. But in laboratory plasmas and in space, they can be uniquely informative.
Lorentz Invariance on Trial
Authors: Pospelov Maxim , Romalis Michael
Published: March 2007

Precision experiments and astrophysical observations provide complementary tests of Lorentz invariance and may soon open a window onto new physics. They have already constrained models of quantum gravity and cosmology.
Ultracold Gases of Fermionic Atoms Offer Another Path to Atom Interferometry
Authors: Levi Barbara Goss
Published: March 2007

One advantage of Fermi gases over Bose–Einstein condensates is the absence of collisions that can destroy an interference pattern.
ITER Impasse Illustrates Challenge of Site Selection
Authors: Feder Toni
Published: March 2007

The more partners in a project, the more resources available, but the more complicated decision making becomes.
Push for Kerry by Scientists Draws Republican Ire
Authors: Dawson Jim
Published: March 2007

A growing number of politically active scientists, dismayed with how science has fared under the Bush administration, are urging their colleagues to work for John Kerry.
Satellite-Observed Changes in the Arctic
Authors: Comiso Josefino C. , Parkinson Claire L.
Published: March 2007

The Arctic has warmed by about 1°C in the past two decades. That time period has seen glaciers retreat, permafrost thaw, snow cover decrease, and ice sheets thin.
Edward Teller’s Scientific Life
Authors: Libby Stephen B. , Weiss Morton S.
Published: March 2007

The young Teller applied the new quantum mechanics theory to understanding molecules. In later years, his interest in nuclear fusion and matter at high energy density meshed naturally with his role in national defense.
Mikael Levonovich Ter-Mikaelian
Authors: Ispirian Karo , Vardanyan Eduard , Fiorito Ralph
Published: March 2007

2
Magnetic Resonance Force Microscope Locates a Single Electron Spin Inside a Glass Slab
Authors: Day Charles
Published: March 2007

With further improvements, the technique could ultimately determine the structures of isolated biomolecules and disordered materials.
New Experiments Highlight Universal Behavior in Copper Oxide Superconductors
Authors: Levi Barbara Goss
Published: March 2007

Similar patterns of spin fluctuations and charge ordering in different compounds suggests that these features are intrinsic to the cuprates.
US Physics Teachers Volunteer in AIDS-Ravaged Zambia
Authors: Dawson Jim
Published: March 2007

With a small grant and a good idea, a group of Virginia physics teachers is working in a remote area of Zambia to prevent physics education from becoming a victim of the AIDS pandemic.
Life’s Universal Scaling Laws
Authors: West Geoffrey B. , Brown James H.
Published: March 2007

Biological systems have evolved branching networks that transport a variety of resources. We argue that common properties of those networks allow for a quantitative theory of the structure, organization, and dynamics of living systems.
New All-Electrical Measurement Schemes Can Detect the Spin State of a Single Electron
Authors: Fitzgerald Richard
Published: March 2007

Spin-to-charge conversion improves prospects for semiconductor-based quantum information processing.
Solid Helium-4 in Bulk Doesn’t Go With the Flow
Authors: Blau Steven K.
Published: March 2007

New observations of an apparent superfluid component close loopholes in an earlier experiment, but present their own set of mysteries.
New Experiments Demonstrate Quantum Optics on a Chip
Authors: Wilson Mark
Published: March 2007

Researchers achieve coherent coupling between a superconducting quantum bit and a single microwave photon.
Ethics and the Welfare of the Physics Profession
Authors: Kirby Kate , Houle Frances A.
Published: March 2007

Responding to a survey by an APS task force on ethics, younger members of the physics community have raised significant concerns about the treatment of subordinates and about other ethical issues.
Physics Nobel Prize Goes to Gross, Politzer, and Wilczek for Their Discovery of Asymptotic Freedom
Authors: Schwarzschild Bertram
Published: March 2007

The strongest force in nature has the peculiar property that quarks become oblivious of one another when the distance between them gets small enough
Debate Over Optics in Early Art Is Focus at OSA Gathering
Authors: Feder Toni
Published: March 2007

The controversy over the use of optical aids by early Renaissance painters is cross-disciplinary and emotionally charged
Computational Science Demands a New Paradigm
Authors: Post Douglass E. , Votta Lawrence G.
Published: March 2007

The field has reached a threshold at which better organization becomes crucial. New methods of verifying and validating complex codes are mandatory if computational science is to fulfill its promise for science and society.
Infrared Detectors for Astrophysics
Authors: Richards Paul L. , McCreight Craig R.
Published: March 2007

Recent advances in materials, system architectures, and microfabrication have spawned a new generation of detectors that can image infrared sources at speeds and spatial resolutions orders of magnitude greater than was possible just a decade ago.
US Visa Difficulties Are Lessening, but More Must Be Done
Authors: Flatten Amy
Published: March 2007

Security concerns remain paramount in the handling of US visas for international students and scientists, but efforts by science and education organizations to improve the process seem to be paying off.
X-Ray Absorption Lines Probe the Missing Half of the Cosmic Baryon Population
Authors: Schwarzschild Bertram
Published: March 2007

Cosmologists believe that half of all ordinary matter in the present epoch is hidden as a web of highly ionized intergalactic gas. An x-ray analog of the Lyman α forest of redshifted ultraviolet absorption lines promises to reveal that missing matter.
A Small Puzzle from 1905
Authors: Harvey Alex , Schucking Engelbert
Published: March 2007

In his first relativity paper, Einstein made one erroneous prediction. Although it should have been withdrawn when he generalized the theory to include gravity, the original error has received surprisingly little attention.
Lab Weds Brain Research and Physics
Authors: Feder Toni
Published: March 2007

Magnets and modeling may help reveal secrets of brain development and disease.
Evidence for a Plasma Inside a Sonoluminescing Bubble
Authors: Levi Barbara Goss
Published: March 2007

The exceptionally bright light emitted by an acoustically vibrated bubble of argon gas in sulfuric acid helps illuminate the extreme conditions within a collapsed bubble.
A String-Theory Calculation of Viscosity Could Have Surprising Applications
Authors: Blau Steven K.
Published: March 2007

A deep connection between strings and gauge symmetries enables theorists to address the dynamics of strongly interacting fluids.
Runaway Breakdown and the Mysteries of Lightning
Authors: Gurevich Alexander V. , Zybin Kirill P.
Published: March 2007

The observed electric fields in thunderclouds are generally too weak to initiate the atmosphere’s electrical breakdown. But cosmic rays can play a surprising role in the drama of lightning.
The Uranium Bomb, the Calutron, and the Space-Charge Problem
Authors: Parkins William E.
Published: March 2007

A participating scientist relates the story of a World War II project dedicated to electromagnetically separating uranium-235 from uranium-238.
An Organic Electronics Primer
Authors: Malliaras George , Friend Richard
Published: March 2007

Weak intermolecular interactions, low dielectric constants, and the availability of a nearly unlimited number of different molecules determine the scope of organic semiconductors as systems for exploring and exploiting solid-state phenomena.
Modeling the Sumatra–Andaman Earthquake Reveals a Complex, Nonuniform Rupture
Authors: Wilson Mark
Published: March 2007

Data from a global network of seismometers were available within minutes of last December’s Sumatran earthquake. Constructing a detailed, self-consistent picture of where, when, how fast, and how much the sea floor moved has taken months.
Limiting Light Pollution Is Ongoing Challenge
Authors: Feder Toni
Published: March 2007

Preserving starlit nights in the face of ever-growing light use is a balancing act that proponents of dark skies approach with education, better light fixtures, and legislation.
Infrared Illuminates Ancient Scrolls
Authors: Guinnessy Paul
Published: March 2007

And the helmets are shaking their purple-dyed crests, and for the wearers of breast-plates the weavers are striking up the wise shuttle’s songs, that wakes up those who are asleep.
Private Donations Fund Theory Institute in Germany
Authors: Feder Toni
Published: March 2007

And the helmets are shaking their purple-dyed crests, and for the wearers of breast-plates the weavers are striking up the wise shuttle’s songs, that wakes up those who are asleep.
Living with a Variable Sun
Authors: Lean Judith
Published: March 2007

Scientific curiosity and societal utility both call for a robust understanding of the Sun-Earth system. Changes—even small ones—in the energy flowing from the Sun can have widespread effects, from climate change to disruptions in satellite communications.
Citation Statistics from 110 Years of Physical Review
Authors: Redner Sidney
Published: March 2007

Publicly available data reveal long-term systematic features about citation statistics and how papers are referenced. The data also tell fascinating citation histories of individual articles.
Politics Shapes Life for Iranian Physicist
Authors: Feder Toni
Published: March 2007

Free on bail and currently visiting the US, an Iranian physicist wonders if it’s safe to go home.
The Nonequilibrium Thermodynamics of Small Systems
Authors: Bustamante Carlos , Liphardt Jan , Ritort Felix
Published: March 2007

The interactions of tiny objects with their environments are dominated by thermal fluctuations. Guided by theory and assisted by new micromanipulation tools, scientists have begun to study such interactions in detail.
Pyroelectricity: From Ancient Curiosity to Modern Imaging Tool
Authors: Lang Sidney B.
Published: March 2007

Changes in the net dipole moment of certain materials form the basis for a broad range of IR detectors.
Doctor Atomic to Premier in San Francisco
Authors: Wilson Mark
Published: March 2007

John Adams’s opera about J. Robert Oppenheimer explores the moral crisis that gripped scientists in the days preceding the Trinity Test in July 1945.
Math and Science Partnership Program Struggling at NSF
Authors: Dawson Jim
Published: March 2007

Congressional supporters are fighting to maintain funding for NSF’s portion of the Math and Science Partnership while the administration pushes to shift the money to the Department of Education.
Einstein Versus the Physical Review
Authors: Kennefick Daniel
Published: March 2007

A great scientist can benefit from peer review, even while refusing to have anything to do with it.
Trapping Ions in Pairs Extends the Reach of Ultraprecise Optical Spectroscopy
Authors: Day Charles
Published: March 2007

Thanks to techniques borrowed from quantum computation, once-unsuitable ions can now be used for atomic clocks.
“The Happy Thirties”
Authors: Schweber Silvan S.
Published: March 2007

Despite the political upheavals of the 1930s, the decade played a pivotal role in Hans Bethe’s life.
Hans Bethe and Quantum Electrodynamics
Authors: Dyson Freeman
Published: March 2007

In 1947 no one knew how to calculate the fine structure of spectroscopic levels of a real electron making transitions in a real hydrogen atom—except Hans Bethe.
Order Parameter of the Chiral Potts Model Succumbs at Last to Exact Solution
Authors: Day Charles
Published: March 2007

Exact solutions are prized because they can be used to compare theory with simulation and experiment without ambiguity. Finding them has sometimes proved arduous.
Transforming Physics Education
Authors: Wieman Carl , Perkins Katherine
Published: March 2007

By using the tools of physics in their teaching, instructors can move students from mindless memorization to understanding and appreciation.
Superconducting Circuits and Quantum Information
Authors: You J. Q. , Nori Franco
Published: March 2007

Superconducting circuits can behave like atoms making transitions between two levels. Such circuits can test quantum mechanics at macroscopic scales and be used to conduct atomic-physics experiments on a silicon chip.
Glauber, Hall, and Hänsch Share the 2005 Nobel Prize in Physics
Authors: Levi Barbara Goss
Published: March 2007

The work of these three helps today’s optical researchers both measure and understand quantum phenomena.
‘Gathering Storm’ Report Urges Strong Federal Action to Save US Science and Technology Leadership
Authors: Dawson Jim
Published: March 2007

A National Academy of Sciences study warns that without strong steps to improve federal support for science and technology, the quality of life in the US is threatened.
High Schoolers Debate Physics at International Tournament
Authors: Feder Toni
Published: March 2007

Whether one detector is moved to Australia or left in Washington State, the upgraded version of the three-pronged Laser Interferometer Gravitational-Wave Observatory is expected to deliver results.
Electrons in atomically thin carbon sheets behave like massless particles
Authors: Wilson Mark
Published: March 2007

Traditionally found in particle-physics and cosmology contexts, the relativistic Dirac equation also describes how electrons move in a unique two-dimensional condensed matter system, graphene.
Benjamin Franklin and lightning rods
Authors: Krider E. Philip
Published: March 2007

Franklin’s work on electricity and lightning earned him worldwide fame and respect—ideal assets for brokering aid from France during the American Revolution.
Experiment tracks the progress of a chaotically mixed chemical reaction
Authors: Day Charles
Published: March 2007

Imaging an electromagnetically stirred tray of chemicals under diverse conditions reveals surprisingly uniform behavior.
Geometrical frustration
Authors: Moessner Roderich , Ramirez Arthur P.
Published: March 2007

When interactions between magnetic degrees of freedom in a lattice are incompatible with the underlying crystal geometry, exotic phenomena such as spin ice and spin liquid phases can emerge.
Rethinking the content of physics courses
Authors: Grayson Diane J.
Published: March 2007

Physics students, particularly in today’s information age, need to understand the unity of physics and the way in which scientific knowledge is generated.
Two hundred years of capillarity research
Authors: Pomeau Yves , Villermaux Emmanuel
Published: March 2007

Two centuries after seminal work by Pierre-Simon Laplace and Thomas Young, capillarity’s modern applications arise in fields ranging from biology and oceanography to propulsion, materials science, and novel devices.
Evidence of exotic trimers sought and found in ultracold gas of cesium atoms
Authors: Day Charles
Published: March 2007

Long-predicted three-atom states form fleetingly when an external magnetic field is tuned to the right resonance.
Acoustic-waveguide sonar finds enormous fish shoals
Authors: Wilson Mark
Published: March 2007

Overfishing has devastated the oceans’ stock of fish. Backscattered echoes of low-frequency signals may provide an accurate census of that stock.
Astronomer unearths evidence of scientific tradition in Africa
Authors: Feder Toni
Published: March 2007

Thebe Medupe, a rising star in South Africa’s astronomy community, hopes his work will attract other young blacks into science and technology.
To redefine kilogram, experiments must weigh in
Authors: Feder Toni
Published: March 2007

Once a discrepancy between experiments disappears, the definitions of the kilogram and three other units will be updated to keep pace with scientific measurement capabilities.
Special report: Bush budget boosts funding for physical sciences in FY 2007; NSF, DOE, and NIST would all do well
Authors: Dawson Jim , Guinnessy Paul
Published: March 2007

Years of relatively flat or declining funding for many of the physical sciences are being reversed in the administration’s budget proposal, but the continuing high cost of the war in Iraq, the war on terrorism, and the growing deficit mean the boon for the physical sciences is not new money but funds being transferred from other science programs.
Albert Einstein in Leiden
Authors: van Delft Dirk
Published: March 2007

During World War I, this university town in neutral Holland was, for Einstein, a respite from the abhorrent chauvinism of German academia. Leiden was also the home of his father figure Hendrik Lorentz and of his dear and tragic friend Paul Ehrenfest.
Genetically engineered fluorescent protein lights up the course of electrical signals in mouse hearts
Authors: Day Charles
Published: March 2007

Muscle cells contract when the internal concentration of calcium ions shoots up. Thanks to a new molecular probe, those peaks can now be tracked in vivo.
Industry and academia join hands in search for post-CMOS logic
Authors: Feder Toni
Published: March 2007

The end of Moore’s law—the halving in size of electronic components every 18 months or so—is approaching. But the law could get a reprieve and lead to a technological and economic gold rush if non-charge-based information manipulation is attained.
Initiating and Strengthening Plasma Research in Developing Countries
Authors: Lee Sing , Wong Chiow San
Published: March 2007

A grass-roots effort begun 20 years ago has blossomed into today’s Asian African Association for Plasma Training. The AAAPT has helped establish vigorous plasma-related programs, including materials processing and fusion studies, around the globe.
Phase-locked femtosecond laser directs the outcome of a simple chemical reaction
Authors: Day Charles
Published: March 2007

The up-down pattern of the electric field within intense optical pulses breaks the left-right symmetry of diatomic dissociation.
Colloidal particles crystallize in an increasingly wide range of structures
Authors: Day Charles
Published: March 2007

Two groups working in different size regimes have found similar recipes for making new and potentially useful materials.
Drops of liquid exhibit surprising self-propulsion on ratcheted surfaces
Authors: Schwarzchild Bertram
Published: March 2007

Cooks use the Leidenfrost effect to see when skillets are hot enough. Some day it may serve to keep microprocessor arrays cool.
Looking back and ahead at condensed matter physics
Authors: Cohen Marvin L.
Published: March 2007

What began as independent and disparate specialties has matured into a unified field whose remarkable diversity has influenced the development of many others, including quantum physics and chemistry, computer science, and engineering.
Scanning tunneling microscope measures the spin-excitation spectrum of atomic-scale magnets
Authors: Wilson Mark
Published: March 2007

A proof-of-principle demonstration sets the stage for creating designer magnets, from simple Heisenberg spin chains to exotic spin ices.
Search for magnetic monopoles at the Tevatron sets new upper limit on their production
Authors: Schwarzschild Bertram
Published: March 2007

Paul Dirac showed in 1931 that the existence of even a single monopole, anywhere, would suffice to explain the universal quantization of electric charge.
CERN chief rethinks LHC fees
Authors: Feder Toni
Published: March 2007

The introduction of a fee to use the LHC is viewed in the US as breaking a deal and opening the floodgates to an unwelcome new paradigm for accessing scientific facilities.
Ultracompact binary stars
Authors: Nelemans Gijs
Published: March 2007

Double stars with tight, rapid orbits enable astronomers to study issues ranging from binary-star evolution to the internal structure of white dwarfs and neutron stars. In addition, they may emit directly observable gravitational waves.
Topological quantum computation
Authors: Das Sarma Sankar , Freedman Michael , Nayak Chetan
Published: March 2007

The search for a large-scale, error-free quantum computer is reaching an intellectual junction at which semiconductor physics, knot theory, string theory, anyons, and quantum Hall effects are all coming together to produce quantum immunity.
InSAR, a tool for measuring Earth’s surface deformation
Authors: Pritchard Matthew E.
Published: March 2007

By comparing phase information from images taken at different times, interferometric synthetic aperture radar can measure terrestrial displacements as small as a centimeter.
Flattened clouds of ultracold atoms display a topological phase transition
Authors: Day Charles
Published: March 2007

When pairs of atom clouds merge and interfere, the resulting fringes embody and reveal the atoms’ collective coherence.
Ultrasensitive searches for the axion
Authors: van Bibber Karl , Rosenberg Leslie J
Published: March 2007

The axion is a hypothetical particle with a mass possibly a trillion times lighter than an electron and exceedingly small couplings to ordinary matter. Yet experiments may soon detect its presence, either as dark matter or as a component of solar flux.
Stories from the early days of quantum mechanics
Authors: Rabi Isidor Isaac , Code R. Fraser
Published: March 2007

A colloquium delivered to the University of Toronto physics department on 5 April 1979 by the master of molecular beams offers a fresh look at an earlier era.
Hurricanes: Tempests in a greenhouse
Authors: Emanuel Kerry
Published: March 2007

Greenhouse gases make Earth’s surface hotter than it would be if the planet were simply a blackbody radiator. That additional warming is an important driver of hurricanes.
Fermi and Pooh: A strange mix
Authors: DeGarmo Denise
Published: March 2007

Some beloved children’s characters played an unexpected role in the science of Enrico Fermi.
From the archives: The stability of the bicycle
Authors: Jones David E. H.
Published: March 2007

Tired of quantum electrodynamics, Brillouin zones, Regge poles? Try this old, unsolved problem in dynamics: How does a bike work?
The vis viva dispute: A controversy at the dawn of dynamics
Authors: Smith George E.
Published: March 2007

The need to augment Newtonian mechanics to encompass systems more complex than collections of point masses engendered a century-long dispute about conservation principles.
Water in polymer electrolyte fuel cells: Friend or foe?
Authors: Eikerling Michael , Kornyshev Alexei A. , Kucernak Anthony R.
Published: March 2007

If fuel cells are to do for the 21st century what combustion engines did for the 19th and 20th, designers must wrestle with the complex role of water—as reaction product, proton shuttle, and asphyxiant.
The man behind Bose statistics
Authors: Wali Kameshwar
Published: March 2007

A rich Bengali cultural tradition, British–Indian politics, and a two-year stint in Europe all helped Satyendra Nath Bose become a renaissance man as well as the originator of quantum statistics.
Hybrid Imaging System Combines X Rays and Magnetic Resonance to Improve Surgical Procedures
Authors: Day Charles
Published: March 2007

Generating and detecting x rays in the strong fields used for magnetic resonance is difficult, but it can be done.
Galaxy Survey Finds Limit of Cosmic Structure Size
Authors: Schwarzschild Bertram
Published: March 2007

Each of the 106 688 points in this scatter plot of redshift against right ascension (celestial longitude) represents a galaxy. Presented by Gavin Dalton (Oxford) and Karl Glazebrook (Johns Hopkins) at the June meeting of the American Astronomical Society in Rochester, New York, this mapping of two cosmic wedges out to 4 billion light years is by far the most extensive three-dimensional galaxy survey to date. The plot summarizes the first two years of the Two Degree Field Galaxy Redshift Survey. The 2dFGRS team is a British-Australian-US collaboration that plans to have measured a total of 250 000 galactic redshifts by the end of next year.
Attenuation of wave in a thin plasma layer by finite-difference time-domain analysis
Authors: Liu Minghai , Hu Xiwei , Jiang Zhonghe , Zhang Shu , Lan Chaohui
Published: March 2007

The attenuation of the electromagnetic wave in a thin plasma layer at high pressure is investigated with finite-difference time-domain method. The effects of the plasma thickness, plasma density distribution function, collision frequency between electron and neutrals, and the frequency of incident wave on the attenuation of the electromagnetic wave are discussed. Numerical results indicate that the phase shift is sensitive to plasma distributions, and the attenuation of wave depends on its frequency, the plasma thickness, plasma density distribution, and collision frequency. In the case of a thin plasma layer, the attenuation of wave is strong only at the low band of frequency for the different distribution functions with a certain collision frequency. Plasmas with a certain thickness for high collision frequency are capable of absorbing microwave radiation over a wider frequency range for the different plasma distributions.
Focus on Test and Measurement
Authors: Rubin Lawrence G.
Published: March 2007

The descriptions of the new products listed in this section are based on information supplied to us by the manufacturers. PHYSICS TODAY can assume no responsibility for their accuracy. To facilitate inquiries about a particular product, a Reader Service Card is attached inside the back cover of the magazine.
Nanoelectromechanical system approaches the quantum detection limit
Authors: Fitzgerald Richard
Published: March 2007

Although a detector’s effects on the object being measured add uncertainty to the measurement, they are not always bad. They can also cool the object.
Science board recommends major hurricane research program
Authors: Dawson Jim
Published: March 2007

With New Orleans and the Gulf Coast still suffering from the devastation of Hurricane Katrina, the NSB wants to reduce vulnerability to future storms through increased research.
Hunting for jobs at liberal arts colleges
Authors: Kane Suzanne Amador , Laws Kenneth
Published: March 2007

Four-year colleges offer special challenges and rewards for physics faculty. Two veterans offer advice to physicists seeking to join their ranks.
Quantum gravity faces reality
Authors: Smolin Lee
Published: March 2007

String theory is only one of many approaches to quantizing general relativity. Increasingly, all those approaches will be judged by how well they accord with experimental data.
Mather and smoot share Nobel physics prize for measuring the cosmic microwave background
Authors: Schwarzschild Bertram
Published: March 2007

In the early 1990s, NASA’s Cosmic Background Explorer first revealed the microwave background’s spectral perfection—and spatial imperfection—required by Big Bang cosmology.
Superconductor forms domains that break time-reversal symmetry
Authors: Day Charles
Published: March 2007

Two interference experiments—one using the Kerr effect, the other using the Josephson effect—confirm strontium ruthenate’s exotic pairing.
Exact variational nonlocal stress modeling with asymptotic higher-order strain gradients for nanobeams
Authors: Lim C. W. , Wang C. M.
Published: March 2007

This article presents a complete and asymptotic representation of the one-dimensional nanobeam model with nonlocal stress via an exact variational principle approach. An asymptotic governing differential equation of infinite-order strain gradient model and the corresponding infinite number of boundary conditions are derived and discussed. For practical applications, it explores and presents a reduced higher-order solution to the asymptotic nonlocal model. It is also identified here and explained at length that most publications on this subject have inaccurately employed an excessively simplified lower-order model which furnishes intriguing solutions under certain loading and boundary conditions where the results become identical to the classical solution, i.e., without the small-scale effect at all. Various nanobeam examples are solved to demonstrate the difference between using the simplified lower-order nonlocal model and the asymptotic higher-order strain gradient nonlocal stress model. An important conclusion is the discovery of significant over- or underestimation of stress levels using the lower-order model, particularly at the vicinity of the clamped end of a cantilevered nanobeam under a tip point load. The consequence is that the design of a nanobeam based on the lower-order strain gradient model could be flawed in predicting the nonlocal stress at the clamped end where it could, depending on the magnitude of the small-scale parameter, significantly over- or underestimate the failure criteria of a nanobeam which are governed by the level of stress.
Nanostructuring and thermoelectric properties of bulk skutterudite compound CoSb3
Authors: Mi J. L. , Zhu T. J. , Zhao X. B. , Ma J.
Published: March 2007

Thermoelectric properties of nanostructured skutterudite CoSb3 have been reported. Nanosized CoSb3 powders were synthesized through a solvothermal route. The bulk materials with average grain sizes of 250 and 150nm were prepared by hot pressing and spark plasma sintering from the solvothermally synthesized CoSb3 powders. Both the samples show n-type conduction and the thermal conductivities are reduced compared with that of the sample prepared by the melt-annealing∕hot pressing method. A thermoelectric figure of merit of 0.61 has been obtained for the unfilled CoSb3 skutterudite by spark plasma sintering, which indicates that nanostructuring is an effective way to improve the thermoelectric properties of skutterudite compounds.
Nonideal gas solvation thermodynamics
Authors: Ben-Amotz Dor , Widom B.
Published: March 2007

General expressions are obtained for the thermodynamic properties of nonideal gases of arbitrary composition. These include the equation of state and solvation thermodynamic functions of mixtures with any number of components, expanded to first order in total number density. The results are expressed in terms of binary second virial coefficients which are in turn related to binary interaction potential energy functions. Solvation thermodynamic functions (at both constant pressure and constant volume) are decomposed into solute-solvent and solvent-reorganization contributions, thus indicating how each of the latter quantities may be experimentally measured. Moreover, the results are used to identify solute-induced changes in solvent thermodynamic functions, as well as nonideal (excess) contributions to chemical reaction equilibria and solvation heat capacities. The effects of a solute on the reorganization energy and chemical potential of a nonideal solvent are shown to differ qualitatively from both the corresponding ideal gas and high density fluid results.
A refined He–LiF(001) potential from selective adsorption resonances measured with high-resolution helium spin-echo spectroscopy
Authors: Riley D. J. , Jardine A. P. , Dworski S. , Alexandrowicz G. , Fouquet P. , Ellis J. , Allison W.
Published: March 2007

The authors have developed a new experimental approach for measuring gas-surface selective adsorption resonances with much higher energy resolution and over a wider range of kinematic conditions than has previously been possible. The technique involves using a He3 spin-echo spectrometer as a Fourier transform helium atom scattering apparatus. The authors applied the technique to the He–LiF(001) system. They developed a new empirical potential for the He–LiF(001) system by analyzing and refining the best existing potentials in the light of the new data set. Following an initial free-particle model analysis, the authors used exact close coupling scattering calculations to compare the existing potentials with the new experimental data set. Systematic differences are observed between the two. The exisiting potentials are modified by simple transformations to give a refined potential that is consistent with and fully reproduces the experimental data. Their technique represents a new approach for developing very high precision empirical potentials in order to test first principles theory.
Theory of the absorption and circular dichroism spectra of helical molecular aggregates
Authors: Eisfeld A. , Kniprath R. , Briggs J. S.
Published: March 2007

A theory of the electronic circular dichroism (CD) and optical rotatory dispersion (ORD) of infinite aggregates exhibiting cylindrical symmetry is presented in which, to the authors’ knowledge, for the first time vibrational structure is included explicitly. It is shown that, with the coherent exciton scattering approximation in the Green function approach, the detailed vibrational structure of the aggregate absorption. CD and ORD bands can be calculated from a knowledge of the electronic coupling and the monomer absorption line shape alone. Detailed model calculations for a single helix are made and the results are used to expose the origin of different spectral features. A good reproduction of experimental J-aggregate spectra is obtained, using the same electronic interaction to fit both absorption and CD spectral line shapes. The theory allows some prediction of aggregate geometry to be made, but it is shown that an unambiguous geometrical assignment can only be made where experimental spectra for light of different propagation directions with respect to the cylinder axis are available.
Bragg-case K⃗g and K⃗0 beam double-crystal synchrotron studies of growth sectors and dislocations in synthetic diamonds
Authors: Wierzchowski W. K. , Moore Moreton
Published: March 2007

A slab of synthetic diamond 4×4×1.5 mm3 has been studied in Bragg-case, simultaneously in reflected and transmitted beams, using a double-crystal topographic method with a synchrotron source of x-rays. The examined diamond had been grown by the reconstitution method and was of a cuboctahedral habit with two large artificially cut surfaces parallel to (001) planes. A very sensitive double-crystal arrangement was used with the 008 diamond reflexion matching the 115¯1 silicon reflexion selecting 0.802 Å radiation. Both reflected K⃗g and transmitted K⃗0 beam topographs revealed the images of dislocations and many details of the growth sector structure. The pairs of topographs thus obtained were not entirely complementary. Apart from the different foreshortening, the transmitted beam topographs were less sensitive and reproduced more distinctly defects closer to the exit surface. The results are compared with those obtained using other methods, especially the single-crystal section and projection topography. The images of dislocations in K⃗g and K⃗0 topographs were compared with theoretical images obtained by numerical integration of the Takagi-Taupin equations, including modeling of impurity segregation in growth bands and taking into account the angular divergence of the monochromatized beam. The applied method provided a reasonable correspondence between the simulated and experimental images and confirmed that the images of dislocation outcrops on the entrance surface dominate both the K⃗g and K⃗0 topographs.
Photoacoustic characterization of carbon nanotube array thermal interfaces
Authors: Cola Baratunde A. , Xu Jun , Cheng Changrui , Xu Xianfan , Fisher Timothy S. , Hu Hanping
Published: March 2007

This work describes an experimental study of thermal conductance across multiwalled carbon nanotube (CNT) array interfaces, one sided (Si-CNT-Ag) and two sided (Si-CNT-CNT-Cu), using a photoacoustic technique (PA). Well-anchored, dense, and vertically oriented multiwalled CNT arrays have been directly synthesized on Si wafers and pure Cu sheets using plasma-enhanced chemical vapor deposition. With the PA technique, the small interface resistances of the highly conductive CNT interfaces can be measured with accuracy and precision. In addition, the PA technique can resolve the one-sided CNT interface component resistances (Si-CNT and CNT-Ag) and the two-sided CNT interface component resistances (Si-CNT, CNT-CNT, and CNT-Cu) and can estimate the thermal diffusivity of the CNT layers. The thermal contact resistances of the one- and two-sided CNT interfaces measured using the PA technique are 15.8±0.9 and 4.0±0.4mm2K∕W, respectively, at moderate pressure. These results compare favorably with those obtained using a steady state, one-dimensional reference bar method; however, the uncertainty range is much narrower. The one-sided CNT thermal interface resistance is dominated by the resistance between the free CNT array tips and their opposing substrate (CNT-Ag), which is measured to be 14.0±0.9mm2K∕W. The two-sided CNT thermal interface resistance is dominated by the resistance between the free tips of the mating CNT arrays (CNT-CNT), which is estimated to be 2.1±0.4mm2K∕W.
Effect of polarization and self-energy on the ground donor state in the presence of conduction band nonparabolicity in GaAs–(Al,Ga)As spherical quantum dot
Authors: Bose M. K. , Midya K. , Bose C.
Published: March 2007

Based on the variational technique, the binding energy associated with the ground donor state in the presence of conduction band nonparabolicity, polarization charge, and self-energy is estimated for a finite-barrier quantum dot, with a hydrogenic impurity located at its center. The overall effect of the conduction band nonparabolicity, polarization charge, and self-energy is found to enhance the ground state binding energy, their influences being most prominent in small dots with high barriers.