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  Mobile version   RSS   Subscribe   Unsubscribe   Archive   Media Kit Feb. 9, 2013
Volume: IV
Number: 4

National Society of Black Physicists    African Physical Society   South African Institute of Physics   African Astronomical Society  











 

Photons in atom cloud could lead to logic gates
Physics World    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Physicists in the U.K. have come up with a new way of storing a handful of photons in an ultra-cold atomic gas, in which strong interactions between neighboring photons can be switched on and off using microwaves. As to be described in a Physical Review Letters paper, the experiment involves holding up to 100 rubidium atoms in an optical trap created at the focus of a laser beam, before two pulses of light are fired at the trapped atoms. One pulse creates a "Rydberg polariton" in a subset of the rubidium atoms. A Rydberg polariton absorbs one and only one photon. The other pulse contains some photonic signal which is absorbed by a single polariton. This signal could hop to adjacent polaritons and be lost, but holding the ensemble of atoms in a microwave field leads to strong interactions that maintain the signal integrity. The team believes that the technique could be used to create optical logic gates in which single photons could be processed one at a time. More



Predicting supernovae through gas ejections
Ars Technica    Share    Share on FacebookTwitterShare on LinkedinE-mail article
A team of astronomers have had the good fortune of finding archived data from the Palomar Transient Factory of a supernova immediately before, during and after the explosion. The PTF optical telescope normally only captures transient events after they have already started. But the relatively long period of observation in this case allowed the team to make detailed comparisons of the system's evolution to plausible models of events leading to a star going supernova. PTR data included observations of gas ejections from supernova SN 2010mc some 40 days before the explosion. SN 2010mc is believed to be a type IIn supernova, given its relatively narrow hydrogen emission line. The observations presented no surprises in terms of being inconsistent with models of type IIn supernova evolution. In fact, the data presents a methodology to predict when other luminous blue variable stars, of which there are nearly two-dozen nearby examples, will go supernova. And this will allow astronomers to point multiple telescopes at multiple wavelengths at these objects to fully capture the event. This work is detailed in Nature. More



Where are the edges of exoplanet habitable zones?
Astrobites    Share    Share on FacebookTwitterShare on LinkedinE-mail article
There are over 800 confirmed exoplanets, nearly another 200 have been detected but not confirmed, and nearly 3000 Kepler candidates. Determining whether or not planets can harbor life assumes that life requires liquid water. For any given star a planetary habitable zone can be defined given the star's surface temperature and subsequent temperature-distance maps. Getting more into the details, scientists can take into account the planet's atmosphere which refracts, reflects and absorbs radiation from the star. It is ultimately the thermodynamic properties and the optical response of the gas mixture in the atmosphere that determines habitability. CO2-rich atmospheres at first lead to warmer planets (the greenhouse effect), until the gas' concentration gets so high that CO2 clouds form, blocking the starlight, thus cooling the planet. Depending on the temperature profile, water may be mainly in the gaseous atmosphere, or on condensed on the surface. At very high temperatures the water cycle is disrupted by photolytic reactions. In a paper to appear in the Astrophysical Journal, a team of researchers describe how new parameters and including the effects of Rayleigh scattering lead to new estimates of habitable zones in our solar systems like ours and several others. It turns out that Earth is just inside our sun's habitable zone. The results give us insight into what other planets can support us if it ever came to that, and if we could ever get there. More

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The effect of magnetic fields on star formation
Astrobites    Share    Share on FacebookTwitterShare on LinkedinE-mail article
In the conceptual model of star formation, gravitational forces countered by outward pressure move molecular gas clouds to condense upon themselves. At some critical density gas clouds ignite in fusion reactions, and alas a star (or stars) are formed. But it turns out that magnetic fields also play a role by countering the inward gravitational force and can have a major effect on whether collapse results in a single protostar or fragmentation into a binary or multiple protostar system. Star formation phenomena happen over many length-scales (1013 km – 105 km) and the combination of fluid, magnetic, ionization and nuclear reaction physics leads to very complex equations. In a new paper, a team of computational astrophysicists have used an advanced adaptive mesh, full-magnetohydrodynamic code to simulate gas dynamics leading to star formation. This new code reproduces well previous results from simulations with models that estimate magnetic effects, a tribute to those models. More powerful computers and advance algorithms, like that reported in this paper, will reveal more detailed physics in future work. More



World's first digital laser designed and built in Africa
The Physics arXiv Blog    Share    Share on FacebookTwitterShare on LinkedinE-mail article
In many applications the cross-beam shape of a laser's output is very important. Generally laser beams have to be shaped external to the laser cavity by complex custom apertures, diffraction gratings and mirrors. In a paper posted on arXiv, physicists at the University of KwaZulu–Natal in South Africa describe a laser with intra-cavity digital holograms as a spatial light modulator. Also the beam shaping inside the cavity can be electronically controlled on-demand via computer. This "digital laser" may be used to implement amplitude-only, phase-only or amplitude and phase modulation by simply altering the digital hologram. More



Insight into fabrication process leads to better superconducting wires
Oak Ridge National Lab    Share    Share on FacebookTwitterShare on LinkedinE-mail article
A group of scientists has discovered how to make better superconducting wires using Bi2Sr2CaCu2Ox, also known as Bi-2212. Until recently, Bi-2212 wires more than a few centimeters long would not carry enough electric current to make it worthwhile to consider them for magnet technology. With this discovery comes the possibility of creating magnetic fields in excess of 30 Tesla, three to four times higher than those generated by present accelerator magnet technology. Scientists had previously shown that the wire's low current density is due to gas bubbles that form during a process that melts and re-solidifies thread-like filaments of Bi-2212. Now researchers have developed a new technique that prevents bubble formation almost entirely by performing the melting and re-solidification of materials under high external gas pressure. The team observed five times higher current in a long wire sample made by the new method compared to an identical sample made by the standard recipe. The fabrication technique is described in a paper posted on arXiv. More



Water on barium fluoride surface stays liquid well below its bulk normal freezing point
SLAC National Accelerator Laboratory    Share    Share on FacebookTwitterShare on LinkedinE-mail article
A team of researchers from the U.S. and Sweden have revealed a surprisingly dense form of water that remained liquid well beyond its typical freezing point. Researchers applied a few nanometer thick film of water on the (111) surface of a BaF2 crystal. Even when the system was cooled below 259 K, the water remained liquid. X-ray absorption and x-ray photoelectron spectroscopic observations and computer simulations of the system are reported in Nature Scientific Reports. The (111) surface of BaF2 was thought to stimulate ice formation since its surface lattice parameter is very close to that of the basal plane of ice Ih. That turned out to not be the case. Water is of course a simple molecule, but has some very unique and unusual properties. In the present system hydrogen bonding and counter ion attractions lead to exotic structures and physiochemical behavior. More



What's next for the Large Hadron Collider?
Symmetry Magazine    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Though finding the Higgs is the most famous result from the LHC, the ATLAS, CMS, LHCb and ALICE experiments — along with the smaller experiments TOTEM and LHCf — have actually discovered a total of three particles. ATLAS found the Chi-b (3P) in December 2011, and CMS discovered the excited baryon Xi(b)* in May 2012. There is still much to be learned about the Higgs, and some hold out hope that supersymmetric particles are lurking somewhere in all the data. ALICE has set new records for producing the hottest quark-gluon plasma ever. But starting in March LHC will go through an 18 month shutdown to upgrade the machine to run at 6.5 TeV. Then more collisions at higher energies will conquer new frontiers in particle physics. More



So you want to apply for an REU ... Here's how
Astrobites    Share    Share on FacebookTwitterShare on LinkedinE-mail article
If you are a sophomore or junior undergraduate, you've probably spent the last month watching your senior friends apply to graduate programs, jobs, and non-academic positions. You may be thinking forward to when you fill out these same applications in the coming years. If you are considering a future in research or academia, two important parts of your application will be letters of recommendations from advisors and a statement about your previous research. One way to enhance both (and have a lot of fun in the process) is by participating in the NSF summer REU programs. Astrobites gives tips on how to apply to these programs. Note that NSF programs are not the only summer research programs available to physics students. DOE, NIST, NASA and NIH all have summer programs as well. More



Increase your options for graduate or REU program admissions
NSBP    Share    Share on FacebookTwitterShare on LinkedinE-mail article
The NSBP GradApps and REUApps services are open to all students and allows them to upload all the elements of an admissions application, including academic and work history, transcripts, letters of recommendation and a personal statement. Graduate and REU programs can subscribe to these databases to increase the programs' applicant pool, while at the same time allowing students can put their credentials in front of more programs than to which they would otherwise apply. More

Journal of Women and Minorities in Science and Engineering
Designed as a unique and much-needed resource for educators, managers and policymakers, the Journal of Women and Minorities in Science and Engineering publishes original, peer-reviewed papers that report innovative ideas and programs for classroom teachers, scientific studies and formulation of concepts related to the education, recruitment and retention of underrepresented groups in science and engineering.

Access now available to NSBP members at www.nsbp.org.


Your timeline for going to graduate school should start now
NSBP    Share    Share on FacebookTwitterShare on LinkedinE-mail article
The cycle for the 2013 entering class is just about over. For those that have applied and been admitted you have several more weeks to make a decision. If entering graduate school in 2014 is your goal your timeline should start now. Almost every program requires the general GRE and nearly half of physics programs require the physics GRE. There is no penalty for taking either exam multiple times (other than the cost). Trying the subject test in April is not a bad strategy, as you will only have two opportunities to take in the Fall. This summer you should practice and take the general GRE as many times as you need. It is computer-based and can be taken at any time at numerous test centers. More

365 Days of Astronomy Podcast
365 Days of Astronomy Podcast publishes daily podcasts, five to 10 minutes in duration. They are written, recorded and produced by people around the world. We are looking for individuals, schools, companies and clubs to provide five to 10 podcasts. You can do as few as one episode or up to 12 episodes (one per month, subject, of course, to our editorial discretion). Our goal is to encourage people to sign up for a particular day (or days) of the year. For more information, see the 365 Days of Astronomy website.




National Society of Black Physicists jobs board postings
NSBP    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Caribbean Science Foundation - Student Program for Innovation in Science and Engineering (SPISE)
Carl Albert Rouse Research Fellowship for Undergraduates
Victor M. Blanco Research Fellowship for Undergraduates
LIGO Summer Undergraduate Research Fellowship (SURF)
Vacuum Equipment Group Leader
Visiting Assistant Professor of Physics
WIPAC Director
Intern
Tenure-Track Faculty Position in Experimental Plasma Physics
Undergraduate Research Assistantship
NanoJapan: International Research Experience for Undergraduates
Research Experiences for Undergraduates: Materials Physics at the University of Florida
Summer Research Student
NASA Postdoctoral Fellowships
Faculty Position in Astrophysical Dynamics
REU summer program on complex materials
REU Student
National Radio Astronomy Observatory Research Experience for Undergraduates
Postdoctoral research associate positions




Latest research from Physical Biology
IOP Science    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Prediction of heart rate response to conclusion of the spontaneous breathing trial by fluctuation dissipation theory

Resting potential, oncogene-induced tumorigenesis, and metastasis: the bioelectric basis of cancer in vivo

Interplay between native topology and non-native interactions in the folding of tethered proteins

A method for computing association rate constants of atomistically represented proteins under macromolecular crowding

Single-molecule studies of DNA transcription using atomic force microscopy

More

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Latest research from Progress in Quantum Electronics
IOP Publishing    Share    Share on FacebookTwitterShare on LinkedinE-mail article
Recent developments in optofluidic-assisted Raman spectroscopy

Chirped pulse laser sources and applications

Carrier-envelope phase stabilization of femtosecond lasers by the direct locking method

Interpreting mid-wave infrared MWIR HgCdTe photodetectors

Chaos and high-level dynamics in coupled lasers and their applications

More


 
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