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.
A large team of scientists have developed a “nanobarrel” molecular container that traps and concentrates light onto single molecule. These nanobarrels, which act as tiny test tubes, have been combined with gold nanoparticles so that researchers can detect what is in each one. The invention could be used as a low-cost and reliable diagnostic test.
A breakthrough has been made in identifying the origin of superconductivity in high-temperature superconductors, which has puzzled researchers for the past three decades. Researchers in the U.K. have found that ripples of electrons, known as charge density waves or charge order, create twisted ‘pockets’ of electrons in these materials, from which superconductivity emerges.
Hydrogen is a neutral atom. Its single electron orbits a single proton, and the net effect is no electrical charge. But what about hydrogen’s antimatter counterpart, antihydrogen? Made of a positron that orbits an antiproton, the antihydrogen atom should be neutral too. Various results have indicated as much, but because the charge of antiatoms is difficult to measure, it has remained an open question.
Normally, keeping glass clean and clear depends on repelling or wiping away water droplets. Or a coating attached to help do this. But researchers in Singapore have discovered that doing just the opposite, collecting water, is the key to keeping a surface clear. Their superhydrophilic coating attracts water to create a uniform, thin, transparent layer.
A remarkable consequence of the rules in quantum mechanics is the ability of a quantum particle to penetrate a potential barrier even though its energy should allow it to travel the classical trajectory. This is the quantum tunnel effect. Physicists in Austria have now directly observed quantum particles transmitting through a whole series of up to five potential barriers under conditions where a single particle could not do the move.
Researchers report evidence for an oceans worth of water deep beneath the U.S. Though not in the familiar liquid form—the ingredients for water are bound up in rock deep in the Earth’s mantle—the discovery may represent the planet’s largest water reservoir. The presence of liquid water on the surface is what makes our “blue planet” habitable, and scientists have tried to figure out just how much water may be cycling between Earth’s surface.
Research is conducted worldwide to develop quantum computers. Quantum computers could tackle specialized computational problems such as integer factorization or big data analysis much faster than conventional digital computers. Quantum computers will use one of a number of possible approaches to create quantum bits to compute and store data, giving them unique advantages over computers based on silicon transistors.
Researchers in Spain have recently demonstrated, through experimentation, that a nonlinear interferometer can outperform an equivalent linear measurement, confirming theoretical predictions that nonlinear systems can outperform their linear counterparts if enough photons are used in the measurement. The result answers a fundamental quantum mechanics questions and could enable more sensitive measurements from interferometers.
Researchers in Germany have converted the frequencies of droplets flowing through thin channels into musical notes. This is more than just a gimmick: The fact that droplets can be controlled so precisely that they become musical instruments means they are also of interest with regard to medical diagnostics applications.
Scientists seeking ways to engineer the assembly of tiny particles measuring just billionths of a meter have achieved a new first: the formation of a single layer of nanoparticles on a liquid surface where the properties of the layer can be easily switched. Understanding the assembly of such nanostructured thin films could lead to the design of new kinds of membranes with a variable mechanical response for a wide range of applications.
SLAC National Accelerator Laboratory scientists have found a new way to produce bright pulses of light from accelerated electrons that could shrink "light source" technology used around the world since the 1970s to examine details of atoms and chemical reactions.
Real invisibility cloaks are complex and only work in certain situations. Physics laws prevent an optical invisibility cloak from making objects in air invisible for any directions, colors or polarization. If the medium is changed, however, it is easier to hide objects. Physicists have now manufactured, relatively simply, and tested an ideal invisibility cloak for diffusive light-scattering media, such as fog or milk.
With precarious particles called polaritons that straddle the worlds of light and matter, Univ. of Michigan researchers have demonstrated a new, practical and potentially more efficient way to make a coherent laser-like beam. They have made what's believed to be the first polariton laser that is fueled by electrical current as opposed to light, and also works at room temperature, rather than way below zero.
Researchers in California have created a nanoscale magnetic component for computer memory chips that could significantly improve their energy efficiency and scalability. The design brings spintronics one step closer to being used in computer systems by adopting a new strategy called “spin-orbit torque” that eliminates the need for a magnetic field for switching processes.
The potential of terahertz waves has yet to be reached because they are difficult to generate and manipulate. Current sources are large devices that require complex vacuum, lasers and cooling systems. A Northwestern Univ. team is the first to produce terahertz radiation in a simplified system. Their room-temperature, compact, continuous terahertz radiation source is six times more efficient than previous systems.
Researchers at the Univ. of Adelaide in South Australia have created a thermometer three times more precise than any existing device, able to measure temperature to 30 billionths of a degree. Using the phenomenon called a “whispering gallery”, which projects sounds, the scientists have designed a crystalline disk that concentrates and reinforces light, allowing them to track a minute difference in speed between red light and green light.
Quantum criticality, the strange electronic state that may be intimately related to high-temperature superconductivity, is notoriously difficult to study. But a new discovery of “quantum critical points” could allow physicists to develop a classification scheme for quantum criticality—the first step toward a broader explanation.
Nanoscale magnetic swirls known as skyrmions can form in certain materials such as thin magnetic films. These tiny vortices pack into dense lattices that are more stable than conventional magnetic domains and can be manipulated with minimal electrical power. Researchers in Japan have now made major progress in understanding this phenomenon by conducting the first 3-D analysis of skyrmion lattices using an electron holography microscope.
Quantum criticality, the strange electronic state that may be intimately related to high-temperature superconductivity, is notoriously difficult to study. But a new discovery of “quantum critical points” could allow physicists to develop a classification scheme for quantum criticality, the first step toward a broader explanation.
At the Technical University of Vienna, a new method has developed to utilize quantum mechanical vibrations for high precision measurements. The well-known concept of the Ramsey interferometer was applied to a complex multi-particle system consisting of hundreds of atoms. By “shaking” them the right way, not only can the internal states of atoms be used for interferometric measurements, but also the collective motion state of all particles.