General Physics Thread

Scientists go to great lengths to extend superlow friction: "When nanosized pieces of graphite slide against each other, there can be virtually no friction between them. For many years, superlow friction, or 'superlubricity,' was known to exist only on the nanoscale. Then in 2012, scientists first demonstrated superlubricity beyond the nanoscale when they discovered the phenomenon in micrometer-sized graphite. Building on this and related research, scientists in a new study have now theoretically shown that superlow friction could extend to lengths of tens of centimeters.

In the new study published in Physical Review Letters, researchers Ming Ma, et al., have theoretically investigated the maximum length of a chain of particles that exhibits superlubricity. Their model shows that this critical length depends on the experimental parameters and the material's properties, especially its stiffness. For very stiff materials, such as carbon nanotubes, the scientists found that superlubricity may hold for up to tens of centimeters, after which it abruptly disappears."

Correlations of quantum particles help in distinguishing physical processes: "Communication security and metrology could be enhanced through a study of the role of quantum correlations in the distinguishability of physical processes, by researchers at the Universities of Strathclyde and Waterloo.

The study involved analysing the impact of quantum steering - the way a measurement performed on a particle can affect another distant particle. The study authors devised a method for both precisely quantifying steering's impact and relating it to the task of distinguishing physical processes.

The research could have significant implications for quantum information processing."

Researchers find easy way to deposit metal nanoparticles on a surface using tape: "A combined team of researchers from Northwestern University in the U.S. and Bilkent University in Turkey has found that ordinary Scotch tape can be used to create a metal nanoparticle surface. In their paper published in the Journal of the American Chemical Society, the team describes how they used ordinary sticky tape to create the surfaces and why it worked so well.

Adding metal nanoparticles to a surface offers a way to confer properties onto it that would not be present otherwise—allowing rubbers to conduct electricity, for example. But, getting metal nanoparticles to adhere to desired products oftentimes involves a lot of time, effort or money (not to mention hazardous waste byproducts) which can detract from its usefulness. In this new effort, the researchers found that common, inexpensive sticky tape provides an opportunity for adding nanoparticles to a surface in a simple, clean way."

Possible discovery in 2015 of a new particle in physics: "The world's largest atom-smasher could help physicists understand mysterious dark matter in the universe, and later this year it may offer a discovery even more fascinating than the Higgs-Boson, researchers say.

The Large Hadron Collider, built by the European Organization for Nuclear Research (CERN), has undergone major upgrades this year will begin its second, three-year run.

CERN says that after a two-year break for upgrades, the LHC will be twice as powerful this time."

The future of electronics—now in 2-D: "The future of electronics could lie in a material from its past, as researchers from The Ohio State University work to turn germanium—the material of 1940s transistors—into a potential replacement for silicon.

At the American Association for the Advancement of Science meeting, assistant professor of chemistry Joshua Goldberger reported progress in developing a form of germanium called germanane."

Researchers have found a way to see light through opaque materials: "Over the past decade, scientists have made huge progress in finding ways to see visible light through opaque materials, and now researchers in the US have found a way to see through a mouse’s ear in real time.

While we've been looking at objects inside the body using X-rays and ultrasound for several decades, the results are still pretty fuzzy and we often need to perform biopsies to really find out what’s going on at a deeper level.

But if we could shine visible light through the body, it would give us far clearer images than any other technique, and would mean we could do away with many intrusive surgeries. We could potentially even use laser light to treat inoperable tumours or brain aneurysms."

edited 16th Feb '15 4:46:16 PM by rmctagg09

Novel solid-state nanomaterial platform enables terahertz photonics: "Compact, sensitive and fast nanodetectors are considered to be somewhat of a 'Holy Grail' sought by many researchers around the world. And now a team of scientists in Italy and France has been inspired by nanomaterials and has created a novel solid-state technology platform that opens the door to the use of terahertz (THz) photonics in a wide range of applications.

During the past decade, materials research has played an essential role in filling the THz gap, beginning with the development of THz quantum cascade lasers, which rely heavily on semiconductor heterostructured artificial nanomaterials. The development of THz spectroscopy, nanospectroscopy and THz imaging expanded the range of powerful tools for the characterization of a broad range of materials—including one-dimensional or two-dimensional semiconductors, biomolecules and graphene."

Nano switch could store memory using coordinated 'dance' of atoms: "In one of the tiniest switches ever made, five atoms appear to "dance" around each other in a complex choreographic sequence, with their final arrangement corresponding to one of two stable states. This concerted motion of multiple atoms is unlike that in other nano switches, which typically involve movement of only a single atom or molecule. The motion of multiple atoms gives the switch a major advantage: due to its stability, it is one of the few atomic-scale switches capable of operating at room temperature instead of cryogenic temperatures."

Novel crumpling method takes flat graphene from 2D to 3D: "Researchers at the University of Illinois at Urbana-Champaign have developed a unique single-step process to achieve three-dimensional (3D) texturing of graphene and graphite. Using a commercially available thermally activated shape-memory polymer substrate, this 3D texturing, or 'crumpling,' allows for increased surface area and opens the doors to expanded capabilities for electronics and biomaterials.

'Fundamentally, intrinsic strains on crumpled graphene could allow modulation of electrical and optical properties of graphene,' explained SungWoo Nam, an assistant professor of mechanical science and engineering at Illinois. 'We believe that the crumpled graphene surfaces can be used as higher surface area electrodes for battery and supercapacitor applications. As a coating layer, 3D textured/crumpled nano-topographies could allow omniphobic/anti-bacterial surfaces for advanced coating applications.'"

edited 17th Feb '15 9:50:09 PM by rmctagg09

Researchers first to observe Higgs boson analogue in superconductors: "The Nobel Prize-winning discovery of the Higgs boson - the 'God particle' believed responsible for all the mass in the universe - took place in 2012 at CERN's Large Hadron Collider, an underground facility where accelerated sub-atomic particles zip around the circumference of a 27-kilometer (16.9-mile) ring-shaped tunnel. But what goes around comes around: more than 50 years ago, the first hint of Higgs was inspired by the study of superconductors - a special class of metals that, when cooled to very low temperatures, allow electrons to move without resistance.

Now, a research team led by Israeli and German physicists has closed a circle, by reporting the first-ever observations of the Higgs mode in superconducting materials.

Unlike the mega-expensive sub-atomic smashups at CERN - a facility that cost about $4.75 billion to build - these findings, presented in the prestigious scientific journal Nature Physics, were achieved through experiments conducted in a regular laboratory at relatively low cost."

Perfect colors, captured with one ultra-thin lens: "A completely flat, ultrathin lens can focus different wavelengths of light at the same point, achieving instant color correction in one extremely thin, miniaturized device."

Could classical theory be just as weird as quantum theory?: "Quantum mechanics is often described as 'weird' and 'strange' because it abandons many of the intuitive traits of classical physics. For example, the ideas that the world is objective, is deterministic, and exists independent of measurement are basic features of classical theory, but do not always hold up in quantum theory. But what if it turns out that these intuitive ideas are not true features of classical physics, either? Would classical theory be just as weird as quantum theory?

In a new study published in Physical Review Letters, physicists Radu Ionicioiu, et al., have shown that the three apparently reasonable classical assumptions mentioned above—objectivity, determinism, and independence—are mutually incompatible with any theory, not only with quantum mechanics. The scientists show that, while any two of the three assumptions are compatible, all three are not. All told, our seemingly reasonable classical assumptions may not be so reasonable after all."

Simulating superconducting materials with ultracold atoms (w/ Video): "Using ultracold atoms as a stand-in for electrons, a Rice University-based team of physicists has simulated superconducting materials and made headway on a problem that's vexed physicists for nearly three decades.

The research was carried out by an international team of experimental and theoretical physicists and appears online this week in the journal Nature. Team leader Randy Hulet, an experimental physicist at Rice, said the work could open up a new realm of unexplored science.

Nearly 30 years have passed since physicists discovered that electrons can flow freely through certain materials—superconductors—at relatively elevated temperatures. The reasons for this high-temperature, or 'unconventional' superconductivity are still largely unknown. One of the most promising theories to explain unconventional superconductivity—called the Hubbard model—is simple to express mathematically but is impossible to solve with digital computers."

Ultra-thin nanowires can trap electron 'twisters' that disrupt superconductors: "Superconductor materials are prized for their ability to carry an electric current without resistance, but this valuable trait can be crippled or lost when electrons swirl into tiny tornado-like formations called vortices. These disruptive mini-twisters often form in the presence of magnetic fields, such as those produced by electric motors.

To keep supercurrents flowing at top speed, Johns Hopkins scientists have figured out how to constrain troublesome vortices by trapping them within extremely short, ultra-thin nanowires. Their discovery was reported Feb. 18 in the journal Physical Review Letters."

Physicists offer a solution to the puzzle of the origin of matter in the universe: "Most of the laws of nature treat particles and antiparticles equally, but stars and planets are made of particles, or matter, and not antiparticles, or antimatter. That asymmetry, which favors matter to a very small degree, has puzzled scientists for many years. Physicists offer a possible solution to the mystery of the origin of matter in the universe."

Study demonstrates an electronic switch based on stereoisomerism: "As devices get smaller and smaller, scientists are running up against limits to how small one can feasibly construct a circuit using bulk materials. Molecular circuits offer a possible solution to overcoming these size constraints, and have led to a growing field merging chemistry with electronics.

One study from lead author Timothy A. Su and a team from Columbia University report the first of its kind single-molecule switch with two distinct conductance phases that is based on the molecule's two stereoisomers. Their work appeared in Nature Chemistry."

Optical features embedded in marine shells may help develop responsive, transparent displays: "The blue-rayed limpet is a tiny mollusk that lives in kelp beds along the coasts of Norway, Iceland, the United Kingdom, Portugal, and the Canary Islands. These diminutive organisms — as small as a fingernail — might escape notice entirely, if not for a very conspicuous feature: bright blue dotted lines that run in parallel along the length of their translucent shells. Depending on the angle at which light hits, a limpet's shell can flash brilliantly even in murky water."

Caging of molecules allows investigation of equilibrium thermodynamics: "High performance materials for gas storage, thermal insulators or nanomachines need a thorough understanding of the behavior of the material down to the molecular level. Thermodynamics, which have been developed two hundred years ago to increase the efficiency of steam engines, typically observes and averages over a large number of molecules. Now a team of scientists has developed a methodology, to investigate the equilibrium thermodynamics of single molecules.

On the search for high performance materials for applications such as gas storage, thermal insulators or dynamic nanosystems it is essential to understand the thermal behavior of matter down to the molecular level. Classical thermodynamics average over time and over a large number of molecules. Within a three dimensional space single molecules can adopt an almost infinite number of states, making the assessment of individual species nearly impossible.

Now researchers from Technische Universität München (TUM) and Linköping University (LIU) have developed a methodology, which allows to explore equilibrium thermodynamics of single molecules with atomic resolution at appreciable temperatures. The breakthrough study is based on two pillars: a technology which allows to cage molecules within two-dimensional nanopores and extensive computational modelling.

New research signals big future for quantum radar: "A prototype quantum radar that has the potential to detect objects which are invisible to conventional systems has been developed by an international research team led by a quantum information scientist at the University of York.

The new breed of radar is a hybrid system that uses quantum correlation between microwave and optical beams to detect objects of low reflectivity such as cancer cells or aircraft with a stealth capability. Because the quantum radar operates at much lower energies than conventional systems, it has the long-term potential for a range of applications in biomedicine including non-invasive NMR scans."

Forbidden atomic transitions: Controlling matter 1,000 times more precisely using high-resolution spectroscopy: "A new twist on an old tool lets scientists use light to study and control matter with 1,000 times better resolution and precision than previously possible. Physicists have demonstrated "ponderomotive spectroscopy," which allows researchers to peer more deeply into the structure of atoms and direct their behavior at a much finer scale. The new technique could have applications in quantum computing."

Breakthrough in organic light emitting diodes technology: "Organic light emitting diodes (OLEDs), which are made from carbon-containing materials, have the potential to revolutionize future display technologies, making low-power displays so thin they'll wrap or fold around other structures, for instance."

First ever photograph of light as a particle and a wave: "Light behaves both as a particle and as a wave. Since the days of Einstein, scientists have been trying to directly observe both of these aspects of light at the same time. Now, scientists have succeeded in capturing the first-ever snapshot of this dual behavior."

Black phosphorus is new 'wonder material' for improving optical communication: "Phosphorus, a highly reactive element commonly found in match heads, tracer bullets, and fertilizers, can be turned into a stable crystalline form known as black phosphorus. In a new study, researchers from the University of Minnesota used an ultrathin black phosphorus film—only 20 layers of atoms—to demonstrate high-speed data communication on nanoscale optical circuits.

The devices showed vast improvement in efficiency over comparable devices using the earlier 'wonder material' graphene."

Light, meet matter: Single-photon quantum memory in diamond optical phonons at room temperature: "Photonic quantum technologies – including cryptography, enhanced measurement and information processing – face a conundrum: They require single photons, but these are difficult to create, manipulate and measure. At the same time, quantum memories enable these technologies by acting as a photonic buffer. Therefore, an ideal part of the solution would be a single-photon on-demand read/write quantum memory. To date, however, development of a practical single-photon quantum memory has been stymied by (1) the need for high efficiency, (2) the read/write lasers used introducing noise that contaminates the quantum state, and (3) decoherence of the information stored in the memory.

Recently, scientists at National Research Council of Canada, Ottawa and Institute for Quantum Computing, University of Waterloo demonstrated storage and retrieval of terahertz-bandwidth single photons via a quantum memory in the optical phonons modes of a room-temperature bulk diamond. The researchers report that the quantum memory is low noise, high speed and broadly tunable, and therefore promises to be a versatile light-matter interface for local quantum processing applications. Moreover, unlike existing approaches, the novel device does not require cooling or optical preparation before storage, and is a few millimeters in size. The scientists conclude that diamond is a robust, convenient, and high-speed system extremely well-suited to evaluating operational memory parameters, studying the effects of noise, and developing quantum protocols."

Na-ion batteries get closer to replacing Li-ion batteries: "As lithium resources continue to decline worldwide, the next generation of portable electronics will most likely be powered by something other than Li-ion batteries. One potential candidate is the sodium-ion (Na-ion) battery, which stands out because sodium is cheaper, non-toxic, and more abundant than lithium.

Currently, one of Na-ion's largest drawbacks is that the batteries take a long time to charge and discharge, and a slow discharge rate does not supply enough power density for high-power applications. In general, there is a tradeoff between the charge/discharge rate and capacity, so that attempts to increase the charge/discharge rate have resulted in severely reduced capacity.

Now in a new study published in the Journal of the American Chemical Society, researchers led by Yong Lei, a professor at the Technical University of Ilmenau in Germany, have achieved a significant improvement in this area. The researchers demonstrated a Na-ion battery that exhibits charge/discharge rate and capacity values that are among the highest achieved for both organic Na-ion and Li-ion batteries. The large improvement may help pave the way toward the integration of Na-ion batteries in portable and wearable electronics."

Magnetic vortices in nanodisks reveal information: "Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Forschungszentrum Jülich (FZJ) together with a colleague at the French Centre National de la Recherche Scientifique (CNRS) in Strasbourg have found a new way to electrically read out the orientation of magnetic vortices in nanodisks. Their method relies on measuring characteristic microwaves emanating from the vortices. The new knowledge about these signals could be used in the construction of extremely small components for novel memory technology or wireless data transmission. The results of the study appear in the current edition of the scientific journal Nature Communications."

Researchers develop the first-ever quantum device that detects and corrects its own errors: "When scientists develop a full quantum computer, the world of computing will undergo a revolution of sophistication, speed and energy efficiency that will make even our beefiest conventional machines seem like Stone Age clunkers by comparison.

But, before that happens, quantum physicists like the ones in UC Santa Barbara's physics professor John Martinis' lab will have to create circuitry that takes advantage of the marvelous computing prowess promised by the quantum bit ('qubit'), while compensating for its high vulnerability to environmentally-induced error.

In what they are calling a major milestone, the researchers in the Martinis Lab have developed quantum circuitry that self-checks for errors and suppresses them, preserving the qubits' state(s) and imbuing the system with the highly sought-after reliability that will prove foundational for the building of large-scale superconducting quantum computers."

Buckybomb shows potential power of nanoscale explosives: "Scientists have simulated the explosion of a modified buckminsterfullerene molecule (C₆₀), better known as a buckyball, and shown that the reaction produces a tremendous increase in temperature and pressure within a fraction of a second. The nanoscale explosive, which the scientists nickname a 'buckybomb,' belongs to the emerging field of high-energy nanomaterials that could have a variety of military and industrial applications."

Sub-micrometer carbon spheres reduce engine friction as oil additive: "Tiny, perfectly smooth carbon spheres added to motor oil have been shown to reduce friction and wear typically seen in engines by as much as 25 percent, suggesting a similar enhancement in fuel economy.

The researchers also have shown how to potentially mass-produce the spheres, making them hundreds of times faster than previously possible using ultrasound to speed chemical reactions in manufacturing."

Simulations provide new insight into emerging nanoelectronic device: "Researchers have used an advanced model to simulate in unprecedented detail the workings of 'resistance-switching cells' that might replace conventional memory for electronics applications, with the potential to bring faster and higher capacity computer memory while consuming less energy."

When temperature goes quantum: "A UA-led collaboration of physicists and chemists has discovered that temperature behaves in strange and unexpected ways in graphene, a material that has scientists sizzling with excitement about its potential for new technological devices ranging from computing to medicine.

Imagine setting a frying pan on the stove and cranking up the heat, only to discover that in a few spots the butter isn't melting because part of the pan remains at room temperature. What seems like an impossible scenario in the kitchen is exactly what happens in the strange world of quantum physics, researchers at the University of Arizona have discovered.

The findings, published in the scientific journal Physical Review B, suggest that quantum effects play a role in how heat moves through a material, challenging that classic notion that heat simply diffuses from a hot spot to a cold spot until the temperature is the same throughout."

New class of monofluoro acylboronates that is stable in air and water: "Boron is the ambivert of atoms. Technically classified as a metalloid, boron can undergo organic reactions, forming covalent bonds like carbon, but it can also form ions resulting in metal-like bonds. Several studies have exploited both of these properties of boron to isolate acylborons, by coordinating the boron to a ligand, similar to a metal-ligand interaction.

Hidetoshi Noda and Jeffrey W. Bode of the Department of Chemistry and Applied Biosciences at ETH Zurich report in the Journal of the American Chemical Society a series of acylborons and determined a new class of bidentate ligands that when the acylborons are coordinated, makes acylboronate compounds that are stable in air, water, and silica gel. These coordinated acylboronates react with hydroxylamines more readily than their potassium acyltriflouroborate (KAT) analogs to produce amides. Additionally, this is the first B-chiral acylboronates that are reported in the literature."

Quantum sensor's advantages survive entanglement breakdown: "The extraordinary promise of quantum information processing—solving problems that classical computers can't, perfectly secure communication—depends on a phenomenon called 'entanglement,' in which the physical states of different quantum particles become interrelated. But entanglement is very fragile, and the difficulty of preserving it is a major obstacle to developing practical quantum information systems.

In a series of papers since 2008, members of the Optical and Quantum Communications Group at MIT's Research Laboratory of Electronics have argued that optical systems that use entangled light can outperform classical optical systems—even when the entanglement breaks down."

New paint makes tough self-cleaning surfaces: "A new paint that makes robust self-cleaning surfaces has been developed. The coating can be applied to clothes, paper, glass and steel and when combined with adhesives, maintains its self-cleaning properties after being wiped, scratched with a knife and scuffed with sandpaper."

Traveling without moving: Quantum communication scheme transfers quantum states without transmitting physical particles: "While Einstein considered quantum entanglement as 'spooky action at a distance,' and those who fully accept entanglement acknowledge it to be counterintuitive, current entanglement-based quantum communication schemes for transferring an unknown quantum state from one place to another require classical transportation of particles between sender and receiver. Now consider this: Recently, scientists in China at Harbin Institute of Technology, Yanbian University and Changchun University demonstrated what is known as a counterfactual approach in which quantum information can be transferred between two distant participants without sending any physical particles between them. The researchers accomplished this by entangling two nonlocal qubits with each other without interaction – meaning that the present scheme can transport an unknown qubit in a nondeterministic manner without prior entanglement sharing or classical communication between the participants. Moreover, the scientists state that their approach provides a new method for creating entanglement that allows two qubits to be entangled without interaction between them."

Hybrid nanowires eyed for computers, flexible displays: "A new process for coating copper nanowires with graphene - an ultrathin layer of carbon – lowers resistance and heating, suggesting potential applications in computer chips and flexible displays.

'Highly conductive copper nanowires are essential for efficient data transfer and heat conduction in many applications like high-performance semiconductor chips and transparent displays,' said doctoral student Ruchit Mehta, working with Zhihong Chen, an associate professor of electrical and computer engineering at Purdue University.

Now, researchers have developed a technique for encapsulating the wires with graphene and have shown that the hybrid wires are capable of 15 percent faster data transmission while lowering peak temperature by 27 percent compared with uncoated copper nanowires."

Popular origami pattern makes the mechanical switch: "An origami paper-folding pattern called the square twist is the basis of a microscopic switch that Cornell physicists say could lead to origami-inspired materials and machines."

Mystery of the dancing droplets solved: "A puzzling observation, pursued through hundreds of experiments, has led researchers to a simple yet profound discovery: under certain circumstances, droplets of fluid will move like performers in a dance choreographed by molecular physics. The unexpected findings may prove useful in semiconductor manufacturing and self-cleaning solar panels."

Largest-scale silicon photonic switch: Low loss optical design enables up to 2,500 switch elements on 1 x 1 cm chip: "Today's explosion of video and Internet data is driving unprecedented traffic demand within datacenters. With data transfer rates exceeding 100 gigabits-per-second (Gb/s), communication between servers requires optical switches with faster switching time (micro-to nano-second level), broader band operation, larger capacity for switching elements and lower energy consumption.

Researchers at the University of California, Berkeley have developed a novel silicon photonic switch, which is the largest-scale and the lowest-energy loss switch reported to date. It features a switching time of sub-micro seconds and a broad bandwidth of hundreds of nanometers."