Aerospace engineers from the Univ. of Illinois, Urbana-Champaign are using the National Science Foundation-supported Stampede supercomputer to explore how jets in general, like those on modern aircraft and inside the human body, generate noise. This is important because no simple explanation of how jets generate noise is currently available, and without this understanding making jets quieter is difficult.
For his doctoral dissertation, Yu Chen developed a novel way to fabricate superconducting nanocircuitry. However, the extremely small zinc nanowires he designed did some unexpected things, including demonstrating dissipation characteristics though only to be present in normal states. After long and careful work, which involved both experimental and theoretical efforts, researchers have found an explanation that fits.
In quantum physics, momentum and position are an example of conjugate variables, connected by Heisenberg’s Uncertainty Principle, which says that both quantities cannot be simultaneously measured precisely. Univ. of Rochester physicists have recently shown that a technique called compressive sensing that offers a way to measure both variables at the same time without violating the Uncertainty Principle.
At the nanoscale, where objects are measured in billionths of meters and events transpire in trillionths of seconds, things do not always behave as our experiences with the macro world might lead us to expect. Water, for example, seems to flow much faster within carbon nanotubes than classical physics says should be possible. Now imagine trying to capture movies of these almost imperceptibly small nanoscale movements.
What is believed to be the smallest force ever measured has been detected by researchers with the Lawrence Berkeley National Laboratory and the Univ. of California, Berkeley. Using a combination of lasers and a unique optical trapping system that provides a cloud of ultracold atoms, the researchers measured a force of approximately 42 yoctonewtons.
By combining advanced mathematics with high-performance computing, scientists have developed a tool that allowed them to calculate a fundamental property of most atoms on the periodic table to historic accuracy, reducing error by a factor of a thousand in many cases. The technique also could be used to determine a host of other atomic properties important in fields like nuclear medicine and astrophysics.
Skyrmions have been observed for the first time using x-rays. An international collaboration of researchers working at the Advanced Light Source observed skyrmions in copper selenite an insulator with multiferroic properties. The results not only hold promise for ultra-compact data storage and processing, but may also open up entire new areas of study in quantum topology.
An international research team led by scientists in Barcelona has developed a material which guides and transports a magnetic field from one location to the other, similar to how an optical fiber transports light or a hose transports water. The magnetic hose consists of a ferromagnetic cylinder covered by a superconductor material, a surprisingly simple design made possible by complicated theoretical calculations and experimentation.
In work that unmasks some of the magic behind memristors and "resistive random access memory," or RRAM, researchers have shown that the metal particles in memristors don't stay put as previously thought. The findings have broad implications for the semiconductor industry and beyond. They show, for the first time, exactly how some memristors remember.
Plasmon tunneling is a quantum-mechanical effect where electrons rapidly oscillate across very closely-spaced metal structures. Using a Titan scanning/transmission electron microscope developed and made by FEI Company, the scientists were able to not only observe this new phenomenon directly, but also control the frequency of the tunneling currents by placing single layers of different molecules between the closely-spaced metal particles.
The absorption of petawatt laser light by solid matter is a crucial problem that has been the subject of theoretical and experimental study for more than two decades. In a newly published paper, Lawrence Livermore National Laboratory scientists have defined, for the first time, a set of theoretical boundaries for the absorption of petawatt laser light.
The world's largest atom smasher is gearing up for its second three-year run after 16 months of maintenance and upgrades. Once the Large Hadron Collider restarts after numerous upgrades, two beams will be fired again within the collider at the same time in opposite directions with the aim of recreating conditions a split second after the Big Bang.
There’s a story about how the modern golf ball, with its dimpled surface, came to be: In the mid-1800s, it’s said, new golf balls were smooth, but became dimpled over time as impacts left permanent dents. Smooth new balls were typically used for tournament play, but in one match, a player ran short, had to use an old, dented one, and realized that he could drive this dimpled ball much further than a smooth one.
The electrons in graphene behave as “massless” particles, yet these electrons also seem to have dual personalities. Phenomena observed in the field of graphene plasmonics suggest that when the electrons move collectively, they must exhibit mass. After two years of effort, researchers at Harvard Univ. have successfully measured the collective mass of “massless” electrons in motion in graphene.
Researchers at CERN have, for the first time, demonstrated the direct decay of the Higgs particle into two fermions. This is another strong indication that the particles discovered in 2012 behave as the standard model of particle physics predicts. The discovery was made by analyzing data gathered at the Large Hadron Collider between 2011 and 2012.
New theoretical physics research reveals rare materials that possess both controllable magnetic and electric polarization properties at near-room temperatures. The discovery could lead to longer battery life and increased memory storage for electronic devices, said Yurong Yang, a research assistant professor at the Univ. of Arkansas.
Physicists in Germany have developed a process to generate improved lenses for x-ray microscopy that provide both better resolution and higher throughput. To accomplish this, they have 3-D x-ray optics for volume diffraction that consist of on-chip stacked Fresnel zone plates. These nanostructures focus the incident x-rays much more efficiently and enable improved spatial resolution below 10 nm.
Seemingly ordinary, water has quite puzzling behavior. Why, for example, does ice float when most liquids crystallize into dense solids that sink? Using a computer model to explore water as it freezes, a team at Princeton Univ. has found that water's weird behaviors may arise from a sort of split personality: At very cold temperatures and above a certain pressure, water may spontaneously split into two liquid forms.
A new facility for using protons to take microscopic images has been commissioned at the ring accelerator of the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. Protons, like neutrons, are the building blocks of atomic nuclei. Similar to x-rays, they can be used to radiograph objects, generating images of them. Protons are able to penetrate hot dense matter that can't be examined with light or x-rays.
A physicist in Russia, Alexander Rozhkov, has presented theoretical calculations which indicate the possible existence of fermionic matter in a previously unknown state. It is defined as a 1-D liquid, which cannot be described within the framework of existing models. According to Rozhkov, the 1-D liquid state of matter is not necessarily one that can be observed with the naked eye on a macroscopic scale.
Imaging and mapping of electric fields at radio frequencies (RF) currently requires the use of metallic structures such as dipoles, probes and reference antennas. To make such measurements efficiently, the size of these structures needs to be on the order of the wavelength of the RF fields to be mapped. This poses practical limitations on the smallest features that can be measured.
Inspired by anomalies that arise in certain mathematical equations, researchers have demonstrated a laser system that paradoxically turns off when more power is added rather than becoming continuously brighter. The finding could lead to new ways to manipulate the interaction of electronics and light, an important tool in modern communications networks and high-speed information processing.
Nanopores may one day lead a revolution in DNA sequencing. By sliding DNA molecules one at a time through tiny holes in a thin membrane, it may be possible to decode long stretches of DNA at lightning speeds. Scientists, however, haven’t quite figured out the physics of how polymer strands like DNA interact with nanopores.
Physicists at the Univ. of Rochester have created a silicon nanocavity that allows light to be trapped longer than in other similarly sized optical cavities. An innovative design approach, which mimics evolutionary biology, allowed them to achieve a 10-fold improvement on the performance of previous nanocavities.
The National Science Foundation has announced a five-year, $4 million award to tackle the challenge of synchronizing time in cyber-physical systems, which are systems that integrate sensing, computation, control and networking into physical objects and infrastructure. The grant brings together expertise from five universities to improve the way computers maintain knowledge of time and synchronize it with other networked devices.