In a marathon, everyone starts at roughly the same place at roughly the same time. But the faster runners will gradually increase their lead, and in the end, the distribution of runners on the street will be very broad. Something similar happens to a pulse of light sent through a medium. The pulse is a combination of different colors (or wavelengths), and when they are sent through a medium like glass, they travel at different speeds.
A potential avenue to quantum computing currently generating quite the buzz in the high-tech industry is “valleytronics,” in which information is coded based on the wavelike motion of electrons moving through certain 2-D semiconductors. Now, a promising new pathway to valleytronic technology has been uncovered by researchers with the Lawrence Berkeley National Laboratory.
The idea of computing systems based on controlling atomic spins just got a boost from new research performed at MIT and Brookhaven National Laboratory. By constructing tiny "mirrors" to trap light around impurity atoms in diamond crystals, the team dramatically increased the efficiency with which photons transmit information about those atoms' electronic spin states, which can be used to store quantum information.
Scientists have demonstrated a nanoscale memory technology for superconducting computing that could hasten the advent of an urgently awaited, low-energy alternative to power-hungry conventional data centers and supercomputers. In recent years, the stupendous and growing data demands of cloud computing, expanded Internet use, mobile device support and other applications have prompted the creation of large, centralized computing facilities.
Understanding this electronic effect in organic molecules is crucial for their use in optoelectronic applications. In their article published in Nature Physics, the research team demonstrates measurements on the organic molecule cobalt phthalocyanine (CoPC) that can be explained only by taking into consideration how electrons in the molecule interact with each other.
NIST scientists have developed a novel method to rapidly and accurately calibrate gas flow meters, such as those used to measure natural gas flowing in pipelines, by applying a fundamental physical principle: When a sound wave travels through a gas containing temperature gradients, the sound wave's average speed is determined by the average temperature of the gas.
Graphene has many desirable properties. Magnetism alas is not one of them. Magnetism can be induced in graphene by doping it with magnetic impurities, but this doping tends to disrupt graphene's electronic properties. Now a team of physicists at the Univ. of California, Riverside has found an ingenious way to induce magnetism in graphene while also preserving graphene's electronic properties.
Unlike Bilbo's magic ring, which entangles human hearts, engineers have created a new microring that entangles individual particles of light, an important first step in a whole host of new technologies. Entanglement is one of the most intriguing and promising phenomena in all of physics. Properly harnessed, entangled photons could revolutionize computing, communications and cyber security.
Since the beginning of recorded time, humans have used materials found in nature to improve their lot. Since the turn of this century, scientists have studied metamaterials, artificial materials engineered to bend electromagnetic, acoustic and other types of waves in ways not possible in nature. Now, a discovery has been made with these synthetic materials that may take engineers one step closer to building microscopes with superlenses.
Scientists at the Univ. of Liverpool have controlled the structure of a material to simultaneously generate both magnetization and electrical polarization, an advance which has potential applications in information storage and processing. The researchers demonstrated that it's possible to unlock these properties in a material which initially displayed neither by making designed changes to its structure.
Theoretical physicists at Rice Univ. are living on the edge as they study the astounding properties of graphene. In a new study, they figure out how researchers can fracture graphene nanoribbons to get the edges they need for applications. New research shows it should be possible to control the edge properties of graphene nanoribbons by controlling the conditions under which the nanoribbons are pulled apart.
One of the reasons solar cells are not used more widely is cost: The materials used to make them most efficient are expensive. Engineers are exploring ways to print solar cells from inks, but the devices don’t work as well. A team of engineers has developed a technique to increase the performance and electrical conductivity of thin films that make up these materials using nanotechnology.
Scientists have long known that the speed of light can be slowed slightly as it travels through materials such as water or glass. However, it has generally been thought impossible for particles of light, known as photons, to be slowed as they travel through free space, unimpeded by interactions with any materials.
New laser-driven compression experiments reproduce the conditions deep inside exotic super-Earths and giant planet cores, and the conditions during the violent birth of Earth-like planets, documenting the material properties that determined planet formation and evolution processes. The experimentsreveal the unusual properties of silica under the extreme pressures and temperatures relevant to planetary formation and interior evolution.
Univ. of Chicago scientists have experimentally observed, for the first time, a phenomenon in ultracold, three-atom molecules predicted by Russian theoretical physicist Vitaly Efimov in 1970. In this quantum phenomenon, called geometric scaling, the triatomic molecules fit inside one another like an infinitely large set of Russian nesting dolls.
Scientists have proved a fundamental relationship between energy and time that sets a “quantum speed limit” on processes ranging from quantum computing and tunneling to optical switching. The energy-time uncertainty relationship is the flip side of the Heisenberg uncertainty principle, which sets limits on how precisely you can measure position and speed, and has been the bedrock of quantum mechanics for nearly 100 years.
Sound waves passing through the air, objects that break a body of water and cause ripples or shockwaves from earthquakes all are considered “elastic” waves. These waves travel at the surface or through a material without causing any permanent changes to the substance’s makeup. Now, researchers have developed a material that has the ability to control these waves.
Yale Univ. astronomers have identified the first “changing look” quasar, a gleaming object in deep space that appears to have its own dimmer switch. The discovery may offer a glimpse into the life story of the universe’s great beacons. Quasars are massive, luminous objects that draw their energy from black holes. Until now, scientists have been unable to study both the bright and dim phases of a quasar in a single source.
Does glass ever stop flowing? Researchers have combined computer simulation and information theory, originally invented for telephone communication and cryptography, to answer this puzzling question. Watching a glass blower at work we can clearly see the liquid nature of hot glass. Once the glass has cooled down to room temperature though, it has become solid and we can pour wine in it or make window panes out of it.
The generation of cosmic magnetic fields has long intrigued astrophysicists. Since it was first described in 1959, a phenomenon known as Weibel filamentation instability has generated tremendous theoretical interest from astrophysicists and plasma physicists as a potential mechanism for seed magnetic field generation in the universe. However, direct observation of Weibel-generated magnetic fields remained challenging for decades.
Scientists from the Univ. of Southampton have developed a new technique to generate more powerful, more energy-efficient and low-cost pulsed lasers. The technique, which was developed by researchers from the university's Optoelectronics Research Centre (ORC), has potential applications in a number of fields that use pulsed lasers including telecommunications, metrology, sensing and material processing.
An international team of physicists has succeeded in mapping the condensation of individual atoms, or rather their transition from a gaseous state to another state, using a new method. The team was able to monitor for the first time how xenon atoms condensate in microscopic measuring beakers, or quantum wells, thereby enabling key conclusions to be drawn as to the nature of atomic bonding.
By zapping ordinary metals with femtosecond laser pulses researchers from the Univ. of Rochester have created extraordinary new surfaces that efficiently absorb light, repel water and clean themselves. The multifunctional materials could find use in durable, low maintenance solar collectors and sensors.
Yale Univ.-led research may have solved one of the biggest mysteries in geology: namely, why do tectonic plates beneath the Earth’s surface, which normally shift over the course of tens to hundreds of millions of years, sometimes move abruptly? A new study says the answer comes down to two things: thick crustal plugs and weakened mineral grains.
The discovery of "topologically protected" electrical conductivity on the surface of some materials whose bulk interior acts as an insulator was among the most sensational advances in the last decade of condensed matter physics, with predictions of numerous unusual electronic states and new potential applications. But many of these predicted phenomena have yet to be observed, until now.