For the first time, an international team of astrophysicists has unraveled how stars blow up in supernova explosions. Using NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), the international collaboration created the first-ever map of radioactive material in a supernova remnant, named Cassiopeia A. The findings reveal how shock waves likely rip apart massive dying stars, and ultimately end their lives.
Using light pulses, a team of scientists succeeded in switching a cloud of about 200,000 ultracold atoms from being transparent to being opaque. This “single-photon-switch” could be the first step in the development of a quantum logic gate, an essential component in the field of quantum information processing.
Using ion beams, researchers in Germany have succeeded in structuring an iron aluminium alloy in such a way as to subdivide the material into individually magnetizable regions at the nanometer scale. The prepared alloy can function as a spin valve, which is of great interest as a component for use in spintronics. Normally, the fabrication of a spin valve is a difficult process involving layering non-magnetic and ferromagnetic layers.
There is a big effort in industry to produce electrical devices with more and faster memory and logic. Magnetic memory elements, such as in a hard drive, and in the future in what is called MRAM (magnetic random access memory), use electrical currents to encode information. However, the heat which is generated is a significant problem, since it limits the density of devices and hence the performance of computer chips.
In the first few microseconds after the Big Bang, the universe was a superhot, superdense primordial soup of quarks and gluons, particles of matter and carriers of force respectively. This quark-gluon plasma cooled almost instantly, but its brief existence set the stage for the universe we know today. To better understand how our universe evolved, scientists are re-creating a quark-gluon plasma in giant particle accelerators.
The dominant methods for studying exoplanet atmospheres are not intended for objects as distant, dim and complex as planets trillions of miles from Earth. Few “hard facts” about exoplanet atmospheres have been collected since the first planet was detected in 1992, and most of the data is of “marginal utility.” An exoplanet expert is now calling for initiatives that will help scientists develop tools to detect and analyze exoplanet spectra.
Technical staff at Westinghouse Electric Company LLC, supported by a light water reactor research team at Oak Ridge National Laboratory, have used a new core simulator to analyze its AP1000 advanced pressurized water reactor. The testing focused on modeling the startup conditions and its “neutronics”: the behavior of neutrons in a reactor core.
A single-walled carbon nanotube grows from the round cap down, so it’s logical to think the cap’s formation determines what follows. But according to researchers at Rice Univ., that’s not entirely so. Theoretical physicist Boris Yakobson and his Rice colleagues found through exhaustive analysis that those who wish to control the chirality of nanotubes would be wise to look at other aspects of their growth.
The heroes and villains in animated films tend to be on opposite ends of the moral spectrum. But they’re often similar in their hair, which is usually extremely rigid or straight and swings to and fro. It’s rare to see an animated character with bouncy, curly hair, since computer animators don’t have a simple mathematical means for describing it. That is, until now.
Superconductor “recipes” are frequently tweaked by swapping out elements or manipulating the valence electrons to strike the perfect conductive balance. Most high-temperature superconductors feature only one orbital impacting performance. But what about introducing more complex configurations? Now, Brookhaven National Laboratory’s physicists have combined atoms with multiple orbitals and precisely pinned down their electron distributions.
For centuries, geologists have recognized that the rocks that line riverbeds tend to be smaller and rounder further downstream. But these experts have not agreed on the reason these patterns exist. Does abrasion reduce the size of rocks significantly, or is it that smaller rocks are simply more easily transported downstream? A new study has arrived at a resolution to this puzzle.
An undesired effect in thin film amorphous silicon solar cells has puzzled the scientific community for the last 40 years. This effect, known as light-induced degradation, is responsible for reducing solar cell efficiency over time. Researchers in Germany have recently demonstrated that tiny voids within the silicon network are partly responsible for 10 to 15% efficiency loss as soon as they are used.
A team in France has greatly miniaturized the light-emitting diode (LED) by creating one from a single polythiophene wire placed between the tip of a scanning tunneling microscope and a gold surface. This nanowire, which is made of the same hydrogen, carbon and sulfur components found in much larger LEDs, emits light only when the current passes in a certain direction.
Modern electronics relies on utilizing the charge properties of the electron. The emerging field of atomtronics, however, uses ensembles of atoms to build analogs to electronic circuit elements. Physicists have built a superfluid atomtronic circuit that have allowed them to demonstrate a tool that is critical to electronics: hysteresis. It is the first time that hysteresis has been observed in an ultracold atomic gas.
Ignition has long been considered the "holy grail" of inertial confinement fusion science. A key step along the path to ignition is to have "fuel gains" greater than unity, where the energy generated through fusion reactions exceeds the amount of energy deposited into the fusion fuel. Though ignition remains the ultimate goal, the milestone of achieving fuel gains greater than one has been reached for the first time ever on any facility.
It's not quite Star Trek communications—yet. But long-distance communications in space may be easier now that researchers have designed a clever detector array that can extract more information than usual from single particles of light. Described in a new paper, the NIST/JPL array-on-a-chip easily identifies the position of the exact detector in a multi-detector system that absorbs an incoming infrared light particle, or photon.
New research at the Univ. of Arkansas reveals a novel magnetoelectric effect that makes it possible to control magnetism with an electric field. The novel mechanism may provide a new route for using multiferroic materials for the application of RAM (random access memories) in computers and other devices, such as printers.
Strange events have long been linked to nights of a full moon, though careful scrutiny dispels any association. So, when signals bounced off the lunar surface returned surprisingly faint echoes on full moon nights, scientists sought an explanation in reason rather than superstition. Still, the most compelling evidence arrived during another event that once evoked irrational fears, on a night when Earth's shadow eclipsed the full moon.
Molecular physicists in The Netherlands have produced images of the changes in direction of colliding nitrogen monoxide molecules (NO) with unprecedented sharpness. By combining a Stark decelerator with advanced imaging techniques, they were able to obtain very high resolution images of the collision processes. The finding sheds light on the wave nature of molecules by imaging what previously had only been theorized.
Engineers are increasingly turning to plasmonic color filters (PCFs) to create and control a broad spectrum of colors for imaging applications. However, PCF light transmission efficiency has been limited to only about 30%, less than half the rate of conventional filters. Researchers have now developed a new PCF scheme that achieves a transmission efficiency of 60 to 70%.
U.S. Army-sponsored researchers have discovered a process for simultaneously storing and dissipating energy within structures that could lead to design rules for new types of active, reconfigurable materials. The study method was derived from an examination of how a species of South American fire ant collectively entangle themselves to form an active structure capable of changing state from a liquid to a solid when subject to applied loads.
Seeking a solution to decoherence, scientists have developed a strategy of linking quantum bits together into voting blocks, a strategy that significantly boosts their accuracy. In a recently published paper, the team found that their method results in at least a five-fold increase in the probability of reaching the correct answer when the processor solves the largest problems tested by the researcher, involving hundreds of qubits.
Topological insulators have been of great interest to physicists in recent years because of unusual properties that may provide insights into quantum physics. But most analysis of such materials has had to rely on highly simplified models. Now, a team of researchers at Massachusetts Institute of Technology has performed a more detailed analysis that hints at the existence of six new kinds of topological insulators.
Lead-free BaTiO3 and KNbO3 ferroelectrics have been known and studied for more than 60 years. However, recent scanning x-ray diffraction studies at Argonne National Laboratory have shown new low-symmetry intermediate phases in these materials that lend a thermotropic character to otherwise well-known phase transitions. The findings show that these transitions in ferroelectrics are closely coupled to the underlying domain microstructure.
Cars inch forward slowly in traffic jams, but molecules, when jammed up, can move extremely fast. New research by Northwestern Univ. researchers finds that water molecules traveling through tiny carbon nanotube pipes do not flow continuously but rather intermittently, like stop-and-go traffic, with unexpected results.