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Category: particle physics – Page 585

Another reason for being in east TN this month.

Genevieve Martin/ORNL This rendering illustrates the excitation of a spin liquid on a honeycomb lattice using neutrons. As with many other liquids, it is difficult to see a spin liquid unless it is “splashed,” in this case by neutrons depicted as moving balls. The misaligned and vibrating spin pair in the middle signifies the ephemeral Majorana fermion constantly in motion. The ripples formed when the neutrons hit the spin liquid represent the excitations that are a signature of the Majorana fermions. The atomic structure on the left signifies the honeycomb alpha-ruthenium trichloride, in which each ruthenium atom has a spin and is surrounded by a cage of chlorine atoms.

Researchers from the U.S. Department of Energy’s Oak Ridge National Laboratory and UT’s Department of Materials Science and Engineering and Department of Physics and Astronomy used neutrons to uncover novel behavior in materials that holds promise for quantum computing.

The findings, published in Nature Materials, provide evidence for long-sought phenomena in a two-dimensional magnet.

Continue reading “ORNL, UT Team Up on Breakthrough That Could Aid Quantum Computing” | >

Very cool.

For more than a decade, biomedical researchers have been looking for better ways to deliver cancer-killing medication directly to tumors in the body. Tiny capsules, called nanoparticles, are now being used to transport chemotherapy medicine through the bloodstream, to the doorstep of cancerous tumors. But figuring out the best way for the particles to get past the tumor’s “velvet rope” and enter the tumor is a challenge scientists are still working out. Drexel University researchers believe that the trick to gaining access to the pernicious cellular masses is to give the nanoparticles a new look—and that dressing to impress will be able to get them past the tumor’s biological bouncers.

Targeted cancer therapy is most effective when the medication is released as close as possible to the interior of a , to increase its odds of penetrating and killing off cancerous cells. The challenge that has faced cancer researchers for years is making a delivery vehicle that is sturdy enough to safely get the medication through the bloodstream to tumors—which is no smooth ride—but is also lithe enough to squeeze through the tumor’s dense extra cellular space—a matrix stuffed with sugars called hyaluronic acid.

In research recently published in the journal Nano Letters, lead author Hao Cheng, PhD, an assistant professor with an appointment in Drexel’s College of Engineering, and affiliation with School of Biomedical Engineering, Science and Health Systems; reports that the way to get past the tumor’s front door has everything to do with how the tiny particle is suited up for the journey.

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Nanostructured samples and materials can be efficiently and reliable characterized using Anton Paar’s SAXSpace small- and wide-angle X-ray scattering (SWAXS) system. Users can obtain the size, shape, and size distribution of nano-sized samples and particle domains with the help of the SAXSpace. The device is ideally suited for the analysis of colloidal, biological (Bio-SAXS), and isotropic samples.

The SWAXS system also has a wide selection of accurate and versatile sample stages to meet each SAXS application. Easy handling and automatic alignment facilitate smooth operation. With the unique combination of robust design, short measurement time, and high system uptime, the device not only provides superior WAXS or SAXS results but also ensures high sample throughput. These capabilities make SAXSpace ideally suited to explore nanostructure in various materials, including surfactants, pharmaceuticals, proteins, foods, polymers, and nanoparticles.

Key Features

The key features of the SAXSpace are as follows:

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University of Oregon physicists have combined light and sound to control electron states in an atom-like system, providing a new tool in efforts to move toward quantum-computing systems.

The work was done on diamond topped with a layer of zinc oxide containing electrical conductors and performed at a temperature of 8 degrees Kelvin (−445.27 Fahrenheit, −265.15 Celsius) — just above absolute zero.

Using sound waves known as surface acoustic waves to change electron states could foster data transfer between quantum bits, the researcher said. The interaction of qubits, as is the case with binary bits in current computing, is seen as vital in building advanced systems.

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The theoretical results of a piece of international research published in Nature, whose first author is Ion Errea, a researcher at the UPV/EHU and DIPC, suggest that the quantum nature of hydrogen (in other words, the possibility of it behaving like a particle or a wave) considerably affects the structural properties of hydrogen-rich compounds (potential room-temperature superconducting substances). This is in fact the case of the superconductor hydrogen sulphide: a stinking compound that smells of rotten eggs, which when subjected to pressures a million times higher than atmospheric pressure, behaves like a superconductor at the highest temperature ever identified. This new advance in understanding the physics of high-temperature superconductivity could help to drive forward progress in the search for room-temperature superconductors, which could be used in levitating trains or next-generation supercomputers, for example.

Superconductors are materials that carry electrical current with zero electrical resistance. Conventional or low-temperature ones behave that way only when the substance is cooled down to temperatures close to absolute zero (−273 °C o 0 degrees Kelvin). Last year, however, German researchers identified the high-temperature superconducting properties of hydrogen sulphide which makes it the superconductor at the highest temperature ever discovered: −70 °C or 203 K.

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Nice read that ties Quantum properties such as tunneling to everything around us including our own blood supply in our bodies.

Objects of the quantum world are of a concealed and cold-blooded nature: they usually behave in a quantum manner only when they are significantly cooled and isolated from the environment. Experiments carried out by chemists and physicists from Warsaw have destroyed this simple picture. It turns out that not only does one of the most interesting quantum effects occur at room temperature and higher, but it plays a dominant role in the course of chemical reactions in solutions!

We generally derive our experimental knowledge of quantum phenomena from experiments carried out using sophisticated equipment under exotic conditions: at extremely low temperatures and in a vacuum, isolating quantum objects from the disturbing influence of the environment. Scientists from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw, led by Prof. Jacek Waluk and Prof. Czeslaw Radzewicz’s group from the Faculty of Physics, University of Warsaw (FUW), have just shown that one of the most spectacular quantum phenomena — that of tunneling — takes place even at temperatures above the boiling point of water. However, what is particularly surprising is the fact that the observed effect applies to hydrogen nuclei, which tunnel in particles floating in solution. The results of measurements leave no doubt: in the studied system, in conditions typical for our environment, tunneling turns out to be the main factor responsible for the chemical reaction!

“For some time chemists have been getting used to the idea that electrons in molecules can tunnel. We have shown that in the molecule it is also possible for protons, that is, nuclei of hydrogen atoms, to tunnel. So we have proof that a basic chemical reaction can occur as a result of tunneling, and in addition in solution and at room temperature or higher,” explains Prof. Waluk.

Continue reading “Exotic quantum effects can govern the chemistry around us” | >

HUGE deal for wearables and biomed technologies.

Researchers from the University of Illinois at Urbana-Champaign have demonstrated a new approach to modifying the light absorption and stretchability of atomically thin two-dimensional (2D) materials by surface topographic engineering using only mechanical strain. The highly flexible system has future potential for wearable technology and integrated biomedical optical sensing technology when combined with flexible light-emitting diodes.

“Increasing graphene’s low light absorption in visible range is an important prerequisite for its broad potential applications in photonics and sensing,” explained SungWoo Nam, an assistant professor of mechanical science and engineering at Illinois. “This is the very first stretchable photodetector based exclusively on graphene with strain-tunable photoresponsivity and wavelength selectivity.”

Graphene—an atomically thin layer of hexagonally bonded carbon atoms—has been extensively investigated in advanced photodetectors for its broadband absorption, high carrier mobility, and mechanical flexibility. Due to graphene’s low optical absorptivity, graphene photodetector research so far has focused on hybrid systems to increase photoabsorption. However, such hybrid systems require a complicated integration process, and lead to reduced carrier mobility due to the heterogeneous interfaces.

Continue reading “Crumpling approach enhances photodetectors’ light responsivity” | >

A strange new property of light, which correlates the spin of a light wave’s electric field with its momentum, could usher in a new age in photonics.

A new discovery links the spin and momentum of light waves, and could mean a major advance in the development of new photonic and spintronic devices.

Scientists from Purdue University have discovered a property of light waves called “spin-momentum locking,” which means that a rotating electric field accompanying light moves in a certain direction according to the photons’ momentum. In other words, light waves spinning counterclockwise move only “forward,” those spinning clockwise move only “backward.”

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Researchers with the University of Cambridge say they have the first real evidence of a new state of matter, some 40 years after it was first theorized.

Known as “quantum spin liquid,” the matter states causes normally unbreakable electrons to fracture into pieces, called “Majorana fermions.” These fermions are an important discovery: Physicists believe the material is crucial to further develop quantum computing. Computers employing Majorana fermions would be able to carry out calculations beyond the scope of modern computers quickly, they say.

Quantum spin liquid explains some of the odd behaviors inside magnetic materials. In these materials, the electrons should behave like small bar magnets, all aligning towards magnetic north when a material is cooled. But not all magnetic materials do this — if the material contains quantum spin liquid, the electrons don’t all line up and become entangled.

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