Waves & Packets
Apr. 14, 2012

Elusive Majorana fermions may be lurking in a cold nanowire
Ars Technica
Collective behavior of atoms and electrons in materials, especially at low temperatures, can give rise to quasiparticles: particle-like excitations that have strikingly different properties than the electrons that form them. Researchers in the Netherlands have reported via Science that they have produced quasiparticles that act like Majorana fermions: electrically-neutral particles that are their own antiparticles, such that if two collide, they annihilate. The interpretation still has some degree of uncertainty because the team was not able to test for some of the predicted properties of Majorana fermions. But if these quasiparticles indeed turn out to be Majorana fermions, that will be the first confirmed detection of them in any physical system.More

Dying sun-like stars drive off dust that seeds other solar systems
Ars Technica
When a star completes its red giant phase it ejects mass from its outer layers, forming beautiful clouds known as planetary nebulae, while the remaining core becomes a white dwarf. Using the Very Large Telescope in Chile, astronomers have measured the light scattered off the ejected matter from three stars nearing the end of their lives. As described in Nature, they found that huge, late-life stars known as asymptotic giants form close to their surfaces large grains of silicate dust such as forsterite (Mg2SiO4) and enstatite (Mg2SiO4), which are then driven outward by photon scattering. This finding has interesting implications for the seeding of interstellar space with the raw ingredients for forming new star systems.More

Graphene capsule reveals nanocrystal growth in action
Physics World
Researchers in the U.S. and South Korea have for the first time managed to achieve high-resolution, atomic-scale transmission electron microscopy images of the process of nanocrystal growth. Liquids are difficult to image with a TEM because the samples have to be encapsulated by membranes that are difficult for electrons to penetrate. This new technique, described in Science, places the liquid sample between monolayers of graphene. Because the graphene walls do not scatter the electrons from the TEM, they are like clear windows that allow researchers to look directly at the liquid inside at better than 0.1 nm resolution. Using this technique, the research team was able to observe site-selective coalescence, structural reshaping after coalescence and surface faceting processes happening in colloidal platinum sample. More

CDF and D0 report precise measurements of W boson mass, predictions of Higgs mass
American Physical Society
Long before LHC-based teams reported hints of the Higgs boson, physicists knew roughly what the Higgs mass had to be from measurements of the W boson. According to the Standard Model, with a precise measurement of the W mass, and a good measurement of the top quark mass, it is possible to predict the mass of the Higgs boson. The CDF and D0 Collaborations at Fermilab are each reporting in Physical Review Letters (CDF, D0) their new measurements of the W mass using datasets containing a total of about 2 million W decays to an electron or muon and a neutrino. In what may be another success for the Standard Model, the predicted mass range for the Higgs that follows from these W mass measurements overlaps with the 115–127 GeV range found by the LHC teams.More

Hydrogen at extremely high pressure
The high pressure behavior of hydrogen has major implications for the interiors of the Jovian planets (the gas giants: Jupiter, Saturn, Neptune and Uranus). New reports are adding to the understanding (or misunderstanding) of hydrogen at very high pressures. In one report published in Physical Review Letters, scientists from the Carnegie Institution of Washington have used diamond anvil techniques to prepare hydrogen samples for synchrotron infrared and optical absorption studies to pressures above 300 GPa and from 12 to 300 K. This team did find semimetallic electronic behavior, but not a fully metallic state that others have suggested. A related report of Raman and visible transmission spectroscopic studies of hydrogen at 315 GPa and 300K indicates a new structural phase that contains a mixture of graphene-like layers, consisting of elongated H2 dimers. More

Cancer therapy gets a boost from new isotope
Los Alamos National Lab
A major problem in cancer therapy is the global shortage of medically useful isotopes such as actinium 225 (Ac-225). Using proton beams, Los Alamos National Laboratory and its partner Brookhaven National Laboratory have presented a solution that could match current annual worldwide production of the Ac-225 in just a few days. A collaboration between Los Alamos, Brookhaven and Oak Ridge national laboratories is developing a plan for full-scale production. The proof-of-concept was presented at a meeting at a meeting of International Atomic Energy Agency last year. But two to three years of production scale-up and process development will be required before Ac-225 can be produced routinely.More

Pulsars could probe space-time around black holes
If a pulsar exists near the center of our Milky Way galaxy, where a giant black hole is thought to lurk, it could shed light on the workings of Albert Einstein's general theory of relativity. Space-time is affected by black holes. By measuring how the separations between the pulses change over time, astronomers can study how the pulsar has been affected by the space-time it plows through. Astronomers have yet to find a pulsar close to Sagittarius A*, the name given to the radio object thought to represent the Milky Way's central black hole. But in a paper published in the March edition of the Astrophysical Journal, an international team of astronomers has outlined their plan to study pulsars' effects on space-time using telescopes like the Green Bank Telescope in West Virginia, the Expanded Very Large Array and the MeerKAT array in South Africa.More

Is sharing the Square Kilometer Array an option?
Nature News
The politics of where to put the Square Kilometer Array may have slipped into a new gear. In March, Nature reported that South Africa, which leads an effort involving seven other African countries, won the recommendation of the SKA Site Advisory Committee, which found the country offered slightly better opportunities. The decision-making board met earlier in April, but did not make a final determination on the site. Several publications have explored the idea of sharing the telescope between the African continent and Australia/New Zealand. The international SKA Organization released a statement saying that it is important to maximize the value from the investments made by both candidate host regions. One option, likely the cheapest, would set up the array's high-frequency antennae on one continent and the low-frequency array on the other. A panel of scientists is due to report on this option in mid-May.More

Controversial science teaching bill to become law in Tennessee
Science Insider
Proponents of a new law in Tennessee suggest all they are trying to do is protect teachers that are trying to develop critical thinking skills on "open" scientific questions such as evolution and global warming. Antagonists to the law assert that the law is unnecessary. It can be used to mislead students away from scientific consensuses and towards anti-science political and religious philosophies. And perhaps the greatest fear is that it can lead to politics and philosophy squeezing out or transmogrifying coverage of actual science in science classrooms. Time will tell, but this innocuous sounding measure may actually be a Trojan horse that leads to students being underserved by their science education.More

Survival strategies for African-American astronomers and astrophysicists
The question of how to increase the number of women and minorities in astronomy has been approached from several directions in the United States, including examination of admission policies, mentoring and hiring practices. These point to departmental efforts to improve conditions for some of the students which has the overall benefit of improving conditions for all of the students. However, women and minority astronomers have managed to obtain doctorates even within the nonwelcoming environment of certain astronomy and physics departments. In a paper posted on arXiv, Dr. Jarita Holbrook, presents six strategies used by African-American men and women to persevere if not thrive long enough to earn their doctorate. In a similar report covered on Physorg.com, two British professors have found that women and people from ethnic minorities have to employ special strategies to overcome institutional discrimination when working in large law firms.More

Pioneering NRL physicist had Tuskegee ties
Naval Research Lab
The U.S. Navy's interest in superconductivity began shortly after World War II when programs at the U.S. Naval Research Laboratory and the Office of Naval Research began exploring the science of superconducting materials for the Navy's technology programs. Around the same time, a highly inspired and motivated postdoctoral scientist, Dr. Warren Elliot Henry, had been seeking to continue research in cryogenics and magnetism. NRL hired Henry to build a high magnetic field laboratory, similar to the Francis Bitter design — a circular metal plate design known to produce the strongest man-made magnetic fields in the world — and bought one of the first commercially sold Collins helium liquefaction facilities — a process developed by Samuel Collins for commercially liquefying helium. With Henry's laboratory up and running, the cryogenic group at NRL became one of the strongest low-temperature physics groups in the world. Having received many awards throughout his career, and having made significant contributions to the fields of radar technology, physical properties and materials physics, and education, Warren Henry passed in 2001 unanimously regarded as a legend amongst African-American physicists. His work continues to be cited in textbooks and scientific journals today. More

Caltech's John Johnson advice on graduate school admission
Society of Physics Students
According to professor John Johnson, no one should care about your physics GRE score. While admissions committees do not like to see below-average scores, there is nothing unusual about students that scored below the 50th percentile on the physics GRE going on to become professors at an elite university. The physics GRE tests a very specific problem-solving skill set and is simply not a good predictor of the success of graduate students. In fact, at least one study has shown that relying on the physic GRE in admissions can actually work against departmental quality and diversity goals, both ethnic and gender. But the fact remains that at least half of the graduate programs in physics and astronomy do require you physics GRE scores, and some professors on admissions committees may take that score very seriously. Still, Johnson advises that while students should take the GRE seriously, the most important thing to do for a successful graduate school application is to participate in research. More

National Society of Black Physicists jobs board postings
NASA Postdoctoral Fellowships
High School Instructor of Physics
Duncan Instructor
Introductory Course Instructor and Manager
Summer Intern
IAU Office of Astronomy for Development: Internship Opportunity
Entrepreneurship for Scientists and Engineers in East Africa
Director, South African Astronomical Observatory
Marshall REU in Scientific Computing
Tenure Track (Open Rank) Faculty Position — Stony Brook Center for Science and Mathematics Education
National Astrophysics and Space Science Program
Postdoctoral Research Associate PositionsMore

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IOP Journal
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Applied Physics Reviews
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