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Apr. 7, 2012
Volume: III
Number: 14
 
National Society of Black Physicists    African Physical Society    South African Institute of Physics   African Astronomical Society   
 
 
Supercomputing the difference between matter and antimatter
Brookhaven National Lab    Share    Share on FacebookTwitterShare on LinkedinE-mail article
An international collaboration of scientists has reported a landmark calculation of the decay process of a kaon into two pions, using breakthrough techniques on some of the world's fastest supercomputers. The new research, reported Physical Review Letters, calculates the process of kaon decay from first principals and is the first quantitative determination of an amplitude for a realistic hadronic weak decay. To capture the decay of individual quarks and the flitting in and out of existence of other subatomic particles, the calculation's length scale had to be on the order of attometers (10-18 m). But they also had to span up to meters, the length over which the decay is observed in the lab. Extending the methods of lattice quantum chromodyamics and Monte Carlo sampling to find the most likely quantum fluctuations of the decay, the researchers were able follow instances of CP violation, which would help explain why there is more matter than antimatter in the universe. More



The 1st results from RENO: Observation of the weakest neutrino transformation
Interactions.org    Share    Share on FacebookTwitterShare on LinkedinE-mail article
The Reactor Experiment for Neutrino Oscillations research team announced their first result of an elusive neutrino transformation mixing angle, which is a quantification of the transformation of one neutrino flavor to another. The RENO measured value of theta one-three is sin213=0.103±0.013(stat.) ±0.011(syst.), excluding no-oscillation hypothesis at 6.3 standard deviations. In March, the Daya Bay Reactor Neutrino Experiment announced their measurement of sin213 as 0.092 ±0.017. Berkeley-based physicist and Daya Bay co-spokesperson, Kam-Biu Luk, remarked to Waves and Packets that the RENO result is very reassuring to the neutrino community in that two large reactor-based experiments have achieved essentially the same result. RENO and Daya Bay have different experimental configurations. Other than one, Daya Bay, being able to collect data faster, there is nothing in the respective designs that should result in drastically different measurements of mixing angles. More data is being collected by both experiments so we can expect updates, and hopefully convergence on a final value. More

Nuclear physicists invalidate shell model for beryllium isotopes
PhysOrg    Share    Share on FacebookTwitterShare on LinkedinE-mail article
The systematic study of atomic nuclei led to a shell model of nuclear structure and the discovery that nuclei that contain a certain "magic" number of protons and neutrons are particularly stable. These so-called magic numbers of protons or neutrons are 2, 8, 20, 28, 50, 82 and 126. But now a team of nuclear physicists and chemists has, for the first time, managed to measure the size of the charge distribution in the atomic nucleus of the highly exotic beryllium-12 isotope. The researchers were surprised to find that the so-called charge radius of beryllium-12 increases in comparison with that of the beryllium-11 isotope, while the radius of the matter distribution was significantly smaller. These experimental findings along with validating theoretical modeling calculations, both reported in Physical Review Letters, contradict the nuclear shell-model and indicate that the number of eight neutrons in beryllium isotopes is no longer a magic number. More



Electrons tunnel nicely through boron nitride monolayers
Physics World    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Ultrathin sheets of hexagonal boron nitride could make for the ideal dielectric layer in future electronic components, thanks to a high degree of uniformity in how electrons tunnel through the material. Like graphene, sheets of boron nitride just one atom thick can be created by the exfoliation of much thicker samples. The two materials have very similar lattice constants. But unlike graphene, h-BN is an insulator. In work reported in Nanoletters, a team of physicists have created electronic devices of h-BN layers of various thicknesses (ranging from one to four atomic layers) between electrode systems of gold, graphene or graphite. The team found that the tunnel current depends exponentially on the number of h-BN atomic layers. This result can lead to graphine/h-BN electronic components such as flexible tunnel devices and ultrafast field-effect transistors. More

Nuclear fusion simulation shows high-gain energy output
R & D Magazine    Share    Share on FacebookTwitterShare on LinkedinE-mail article
A series of computer simulations performed at Sandia National Laboratories has predicted that high-gain nuclear fusion could be achieved in a preheated cylindrical container immersed in strong magnetic fields. If the simulations, reported in Physical Review Letters, bear out in experiments, magnetized inertial fusion could produce reliable electricity from seawater. The MIF technique heats the fusion fuel (deuterium-tritium) by compression as in normal inertial fusion, but uses a magnetic field to suppress heat loss during implosion. The magnetic field acts like a kind of shower curtain to prevent charged particles like electrons and alpha particles from leaving the party early and draining energy from the reaction. Tests of physical equipment necessary to validate the computer simulations are already under way at Z, and a laboratory result is expected by late 2013. More

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Extreme pressure could force hydrogen into a high-temperature superconductor
Ars Technica    Share    Share on FacebookTwitterShare on LinkedinE-mail article
New calculations reported in the Proceedings of the National Academy of Sciences suggest that a calcium hydride compound could have a superconductivity critical transition temperature as high as 235 K (-38° C). But the material must be subjected to pressures of approximately 150 gigapascals (150 GPa, or approximately 1.5 million atmospheres), pressures more typical of geological processes. The key to the pressure-driven transformation is the formation of a clathrate, or cage-like structure in the crystal lattice. The predicted electronic structure may allow the coupling between the phonons and electrons, leading to superconductivity. That a material becomes superconductive at pressures found deep in planetary cores may have implications for planetary and stellar magnetism. More

2012 Quadrennial Physics Congress
Important Deadline Approaching
PhysCon Chapter Reporter Award — April 15
Would your college physics club/SPS Chapter like $500 to help offset your expenses to the 2012 PhysCon, as well as the chance to share your experiences with others? More

The 2012 Quadrennial Physics Congress, hosted by Sigma Pi Sigma, the physics honor society. This meeting will take place Nov. 8-12 in Orlando, Fla., and will center on the theme Connecting Worlds Through Science & Service. Undergraduates, practicing physicists and physics alumni from a broad spectrum of career paths will gather together to address the interconnectivity of the modern world and what it means to science.

Important dates
Sept. 17 — Early Registration Deadline
Oct. 15 — Registration Deadline, Artwork Submission Deadline, Abstract Submission Deadline


Key feature of astrophysical and planetary dynamos reproduced in laboratory
American Physical Society    Share    Share on FacebookTwitterShare on LinkedinE-mail article
It is commonly accepted that most celestial bodies maintain magnetic fields through the dynamo effect: conversion of the kinetic energy of an electrically conducting, but electrically neutral, fluid or plasma into magnetic energy. The dynamo effect has been simulated numerically many times by solving the Navier-Stokes equation coupled to reduced Maxwell equations. Dynamo experiments are challenging because they need to operate at magnetic Reynolds numbers (large volumes, high velocities) large enough for magnetic fields to self-generate. But a recent paper in Physical Review Letters describes dynamo experiments that study the puzzling phenomenon of localized fields. Their experimental rig consisted of a cylinder with two rotating disks located near the two ends of the cylinder. Asymmetric velocity fields could be set up by rotating the cylinders at different rates and even in different directions. The researchers found that moderate asymmetry in the velocity field caused the largest asymmetry and strongest localization in the magnetic field. This result may be related to the so called Maunder minimum, the period from 1645 to 1715 during which the sun had few sunspots, and those which existed appeared on only one hemisphere, suggesting a magnetic field confined to one hemisphere. More



A magnetic surprise for Venus Express
European Space Agency    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Venus is a rarity among planets in that it does not internally generate a magnetic field. Despite the absence of a large protective magnetosphere, the near-Venus environment does exhibit a number of similarities with planets such as Earth. The latest, surprising similarity, described in Science, is the evidence for magnetic reconnection in Venus' induced magnetotail, found recently by the European Space Agency's Venus Express spacecraft. Spacecraft observations over many decades have shown that magnetic reconnection occurs frequently in the magnetospheres of magnetized planets. Until now, reconnection was not generally thought to occur on nonmagnetized planets. In magnetized planets, magnetic tails and magnetic reconnection are caused by deflections of the solar wind in the magnetosphere. In the case of Venus' these are caused by interactions between the solar wind and the planet's ionosphere. For years, researchers have been puzzled over mysterious flashes of light coming from Venus, and some have even speculated that they might be caused by magnetic reconnection, equivalents to the Northern and Southern lights on Earth. But until now they lacked any direct evidence of magnetic interactions around Venus. More

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JILA team demonstrates 'A New Way of Lasing': A 'Superradiant' Laser
National Institute of Standard and Technology    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Physicists at JILA have demonstrated a novel "superradiant" (aka "cooperative spontaneous radiation" or "superfluorescence") laser design, which has the potential to be 100 to 1,000 times more stable than the best conventional visible lasers. Described in Nature, the JILA laser prototype relies on a million rubidium atoms doing a sort of synchronized line dance to produce a dim beam of deep red laser light. In an ordinary laser there is some wobble in the output wavelength due to cavity vibrations. In the new JILA laser that does not happen because the atoms on the line are constantly being energized (by another laser) and subsequent emitting synchronized photons (when they relax). These photons escape before they have a chance to become scrambled by the cavity vibrations and disrupt the synchronized atoms. Though dim, the laser beam's wavelength is very stable. This new lasing method can be transferred by using it as part of a feedback system to "lock" a normal laser's output, increasing stability by two to three orders of magnitude over today's best lasers. More



NASA's Kepler observatory to continue hunt for strange new worlds
Christian Science Monitor    Share    Share on FacebookTwitterShare on LinkedinE-mail article
NASA's prolific Kepler space observatory, which has found signs of thousands of alien planets, will keep hunting strange new worlds for at least four more years. Funding for the Kepler mission, which has discovered more than 2,300 potential alien planets to date, was slated to run out this November. But a NASA review committee has recommended the telescope's planet-hunting effort be extended through at least fiscal year 2016. Because of the three-transit requirement, most of the worlds Kepler has found so far zip around their stars relatively quickly, in close-in orbits. Granting Kepler at least four more years gives it a chance to look for planets in more distant orbits, allowing the telescope to survey the habitable zones of warmer stars. More

The most sensitive weight scale ever can weigh individual protons
IO9    Share    Share on FacebookTwitterShare on LinkedinE-mail article
A new subatomic weight scale can measure masses as tiny as one yoctogram (10-24 g), less than the mass of a proton (1.7 yoctograms). A yoctogram is so tiny that it's effectively the endpoint of the metric system — there aren't any prefixes to describe units smaller than it. Until now, the most sensitive scales could only determine an object's mass to within 100 yoctograms. As described in Nature Nanotechnology, this new nanomechanical is a carbon nanotube of length ~150 nm that vibrates at a frequency of almost 2 GHz. These ultrasensitive nanotube resonators could have applications in mass spectrometry, magnetometry and surface science. More

International Conference of Physics Students
The International Conference of Physics Students is an annual conference of the International Association of Physics Students. Usually, up to 400 students from all over the world attend the event. The 2012 ICPS will be held in the Netherlands in Aug. 4-10. During this week, approximately 400 students from around the world can enjoy lectures from top-class physicists, trips to scientific institutions and cultural excursions. Registration opens in February at www.icps2012.com.


Giant Magellan Telescope tells NSF 'no thanks'
Science Insider    Share    Share on FacebookTwitterShare on LinkedinE-mail article
The organization behind the $700 million Giant Magellan Telescope has decided not to seek any financial help from the U.S. government to build its 24.5-meter telescope. Its decision leaves the $1 billion Thirty Meter Telescope project as the sole contender for federal support, should the U.S. government be able to afford it in the future. Although each team has raised a significant share of the needed funds from private sources and international partners, both had also been counting on a large contribution from the National Science Foundation. However, in late December, NSF announced that it did not anticipate having money to fund either project until sometime in the next decade. The agency did however offer $1.25 million over five years for the development of a public-private partnership plan that might lead to the building of a large telescope. TMT will proceed with its proposal to NSF, but the GMT team has opted out. More

Gravitational Wave Astronomy Workshop
The South African Institute of Physics in collaboration with U.S.-based Laser Interferometer Gravitational Wave Observatory will be hosting a workshop from May 31-June 1 to promote gravitational wave astronomy in Africa. The workshop will cover an overview of the field, including laser interferometry, data analysis, numerical relativity, approximate analytic methods, source modeling and astrophysical implications, pulsar timing and current African activity in gravitational wave astronomy.


LHC physics data taking gets under way at new record collision energy of 8 TeV
Symmetry Breaking    Share    Share on FacebookTwitterShare on LinkedinE-mail article
LHC operators have brought stable beams of protons into collisions at the record-breaking energy of 8 TeV — 4 TeV per beam — for the first time. This marked the beginning of the LHC experiments' data-taking for physics for 2012. "The increase in energy is all about maximizing the discovery potential of the LHC," said CERN Research Director Sergio Bertolucci. "And in that respect, 2012 looks set to be a vintage year for particle physics." More



Lessons learned (so far) from the superluminal neutrino episode
Waves and Packets    Share    Share on FacebookTwitterShare on LinkedinE-mail article
With the March 15 paper of the ICARUS group claiming no advance effect for their (seven) neutrino events, it seems the urgency and interest in this matter is dwindling. OPERA spokesperson Antonio Ereditato and experimental coordinator Dario Autiero have announced their resignations, following a controversial vote of "no confidence" from the collaboration's other leaders. Waves and Packets has asked three distinguished physicists what they think the lessons learned are from the entire episode.

"It is misconception that Einstein's special theory of relativity says that nothing can travel faster than the speed of light. For example, electrons can travel faster than the speed of light in water. This leads to a phenomena known as Cherenkov radiation which is seen as a blue glow in nuclear reactors. In addition, for a long time it's been speculated that subatomic particles known as a tachyons might exist. Tachyons are theoretically predicted particles that travel faster than the speed of light in a vacuum and are consistent with Einstein's theory of relativity. For ordinary subliminal particles light acts as a barrier from above. That is ordinary matter cannot be accelerated to the speed of light. For superluminal tachyons light acts as a barrier from below. That is to say that tachyons cannot be decelerated to the speed of light. It has been conjectured that tachyons could be used to send signals back in time. To date tachyons have not been observed experimentally." Ronald Mallett, University of Connecticut-Storrs

"I think the first thing the whole episode indicates is that there is still enormous public interest in our field. The need to explore is still felt keenly so we need to be clear that announcing results, even controversial ones, should be respected by scientists if proper peer review of those results has been performed. It also points out the absolute necessity of following through on external checks. Public review of the scientific process is not a bad thing nor is showing some humility and skepticism even about 'sacred' principles like special relativity. Episodes like this one give us the opportunity to address misconceptions like those surrounding the connection between special relativity and the speed of light. Showing fallibility doesn't weaken us as long as we remain appropriate demanding of 'extraordinary proof' for "extraordinary results." Larry Gladney, University of Pennsylvania

"I can think of two positive remarks to be made. The first is that, given an information leak from someone familiar with the OPERA experiment to Science magazine, the OPERA Collaboration did the right thing in going public with the information they had at hand. In the spirit of good science, they nearly begged other experiments to validate or invalidate their working hypothesis of superluminal neutrinos. It now appears that invalidation was in order, as reported by the ICARUS experiment. Over the next several months, we may anticipate half a dozen experiments on three continents providing further measurements of neutrino speed; new data will also be forthcoming from the OPERA and ICARUS experiments. My second positive remark is that many of us have been pushed by the OPERA claim to examine the deeper meaning of Special and General Relativity. While paradoxes, such as superluminal travel with inherent negation of cause and effect, are mathematically consistent with Einstein's equations, they generally are hidden behind horizons, or require invocation of new physics such as negative energy, extra dimensions, sterile neutrinos, etc. It has been fun and educational to think about the possibilities. Any opportunity to explore a guarded secret of Nature must be seized upon. It unfortunately appears now that superluminal neutrino travel may not be one of Her guarded secrets." Thomas Weiler, Vanderbilt University

What's your view? Contact Waves and Packets at editors@wavesandpackets.org.


Teaching future scientists to talk
Chronicle of Higher Education    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Much has been written about the need for scientists to speak more plainly and compellingly about their research. Yet complaints about their poor communication skills continue unabated in the popular and academic press and in agencies that finance their work. But perhaps it's too late to work on those communication skills once scientists are already established. Two faculty members at the University of Missouri have devised a program, with support from the Howard Hughes Medical Institute, that seeks to build and maintain those skills early—in undergraduates who are exploring research careers by working in life-science laboratories. More







National Society of Black Physicists jobs board postings
NSBP    Share    Share on FacebookTwitterShare on LinkedinE-mail article
High School Instructor of Physics
Advanced Topics in Astrostatistics
Assistant In Materials Instrumentation and Facilities- National High Magnetic Field Laboratory
Duncan Instructor
Introductory Course Instructor and Manager
Summer Intern
IAU Office of Astronomy for Development: Internship Opportunity
Postdoctoral Associate
Entrepreneurship for Scientists and Engineers in East Africa
Director, South African Astronomical Observatory
Marshall REU in Scientific Computing
Research in Sustainable Energy for sub-Saharan Africa
Notre Dame Physics REU Program
Tenure Track (Open Rank) Faculty Position - Stony Brook Center for Science and Mathematics Education
HBCU STEM Fellowship Program
National Astrophysics and Space Science Programme
Postdoctoral Research Associate Positions




Latest research from New Journal of Physics — Focus on antimatter physics and chemistry
IOP Journal    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Directed fluxes of positronium using pulsed travelling optical lattices

Positron lifetime spectroscopy with optical excitation: A case study of natural diamond

Effect of positron–atom interactions on the annihilation gamma spectra of molecules

Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

Positron collisions with Rydberg atoms in strong magnetic fields

Plans for the creation and studies of electron–positron plasmas in a stellarator
More

Latest research from JCP: BioChemical Physics
JCP: BioChemical Physics    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Quantum dynamics in continuum for proton transport—Generalized correlation

Multilayer coarse-graining polarization model for treating electrostatic interactions of solvated α-conotoxin peptides

Nucleation of colloids and macromolecules: Does the nucleation pathway matter?

Langevin dynamics simulation of polymer-assisted virus-like assembly

A resonance mechanism of efficient energy transfer mediated by Fenna-Matthews-Olson complex
More

 

 
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