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Dec 24, 2024

Machine learning speeds up prediction of materials’ spectral properties

Posted by in categories: particle physics, robotics/AI

Many techniques in computational materials science require scientists to identify the right set of parameters that capture the physics of the specific material they are studying. Calculating these parameters from scratch is sometimes possible but costs a lot of time and computational power. Consequently, scientists are always eager to find more efficient ways to estimate them without doing the full calculation.

This is the case for Koopmans functionals, a promising approach to expand the power of density-functional theory so that it can be used to predict the spectral properties of materials (such as what frequencies of light a material absorbs), and not just their ground state (such as the optimal positions of the atoms in that material). The accuracy of Koopmans functionals relies on finding the right “ parameters” for the system one is studying.

“You can interpret the screening parameters as the degree to which the rest of the electrons in a system react to the addition or removal of an electron,” explains Edward Linscott, a postdoc at the Center for Scientific Computing, Theory and Data of the Paul Scherrer Institute, and member of MARVEL.

Dec 24, 2024

High-quality nanodiamonds offer new bioimaging and quantum sensing potential

Posted by in categories: biological, chemistry, nanotechnology, particle physics, quantum physics

Quantum sensing is a rapidly developing field that utilizes the quantum states of particles, such as superposition, entanglement, and spin states, to detect changes in physical, chemical, or biological systems. A promising type of quantum nanosensor is nanodiamonds (NDs) equipped with nitrogen-vacancy (NV) centers. These centers are created by replacing a carbon atom with nitrogen near a lattice vacancy in a diamond structure.

When excited by light, the NV centers emit photons that maintain stable spin information and are sensitive to external influences like magnetic fields, electric fields, and temperature. Changes in these spin states can be detected using optically detected (ODMR), which measures fluorescence changes under .

In a recent breakthrough, scientists from Okayama University in Japan developed nanodiamond sensors bright enough for bioimaging, with spin properties comparable to those of bulk diamonds. The study, published in ACS Nano, on 16 December 2024, was led by Research Professor Masazumi Fujiwara from Okayama University, in collaboration with Sumitomo Electric Company and the National Institutes for Quantum Science and Technology.

Dec 24, 2024

Printable laser-emitting droplets offer new display technology

Posted by in categories: innovation, materials

Researchers at the University of Tsukuba have developed an innovative method for rapidly creating laser light sources in large quantities using an inkjet printer that ejects laser-emitting droplets.

By applying an electric field to these droplets, the researchers demonstrated that switching the emission of light on and off is possible. Furthermore, they successfully created a compact laser by arranging these droplets on a circuit board.

The study is published in Advanced Materials.

Dec 24, 2024

Scientists reinvent equations governing formation of snowflakes, raindrops and Saturn’s rings

Posted by in categories: engineering, information science, mathematics, particle physics, space

Skoltech researchers have proposed novel mathematical equations that describe the behavior of aggregating particles in fluids. This bears on natural and engineering processes as diverse as rain and snow formation, the emergence of planetary rings, and the flow of fluids and powders in pipes.

Reported in Physical Review Letters, the new equations eliminate the need for juggling two sets of equations that had to be used in conjunction, which led to unacceptable errors for some applications.

Fluid aggregation is involved in many processes. In the atmosphere, agglomerate into rain, and ice microcrystals into snow. In space, particles orbiting come together to form rings like those of Saturn.

Dec 24, 2024

Synchrotron study measures largest magnetic anisotropy of a single molecule

Posted by in categories: chemistry, computing, nanotechnology

At the Berlin synchrotron radiation source BESSY II, the largest magnetic anisotropy of a single molecule ever measured experimentally has been determined. The larger a molecule’s anisotropy is, the better suited it is as a molecular nanomagnet. Such nanomagnets have a wide range of potential applications, for example, in energy-efficient data storage.

Researchers from the Max Planck Institute for Kohlenforschung (MPI KOFO), the Joint Lab EPR4Energy of the Max Planck Institute for Chemical Energy Conversion (MPI CEC) and the Helmholtz-Zentrum Berlin were involved in the study.

The research involved a bismuth complex synthesized in the group of Josep Cornella (MPI KOFO). This molecule has unique magnetic properties that a team led by Frank Neese (MPI KOFO) recently predicted in . So far, however, all attempts to measure the magnetic properties of the bismuth complex and thus experimentally confirm the theoretical predictions have failed.

Dec 24, 2024

Seeking Signatures of High-Energy Vortex States

Posted by in categories: nuclear energy, particle physics

Photons, electrons, and other particles can propagate as wave packets with helical wave fronts that carry an orbital angular momentum. These vortex states can be used to probe the dynamics of atomic, nuclear, and hadronic systems. Recently, researchers demonstrated vortex states of x-ray photons and proposed ways to realize such states for particles at higher energies (MeV to GeV). But verifying high-energy vortex states will be challenging, because characterization techniques used at lower energies would perform poorly. Zhengjiang Li of Sun Yat-sen University in China and his colleagues at Shanghai Institute of Optics and Fine Mechanics propose a new diagnostic method for high-energy vortex states. Their approach would reveal such states through an exotic scattering phenomenon called a superkick.

A superkick is a theorized effect occurring when an atom placed near the axis of a vortex light beam absorbs a photon. Under such conditions, the atom may get kicked to the side with a transverse momentum greater than that carried by the photon. Li and his colleagues considered a similar superkick involving electrons. They analyzed the elastic head-on collision of two electron wave packets at 10 MeV, one in a vortex state and the other in a nonvortex one. According to their calculations, two electrons in the beam, upon scattering, would acquire a nonzero total transverse momentum that could be detectable. The researchers predict an unmistakable signature of the vortex state: The momentum imbalance increases as the collision point gets closer to the vortex axis.

The researchers expect the superkick effect—which has never been observed—to be detectable with realistic experimental settings. They say the idea could be extended to high-energy vortices of photons, ions, and even hadrons.

Dec 24, 2024

Toward a Second Law for Living Systems

Posted by in categories: biological, law, physics

A new theory related to the second law of thermodynamics describes the motion of active biological systems ranging from migrating cells to traveling birds.

In 1944, Erwin Schrödinger published the book What is life? [1]. Therein, he reasoned about the origin of living systems by using methods of statistical physics. He argued that organisms form ordered states far from thermal equilibrium by minimizing their own disorder. In physical terms, disorder corresponds to positive entropy. Schrödinger thus concluded: “What an organism feeds upon is negative entropy […] freeing itself from all the entropy it cannot help producing while alive.” This statement poses the question of whether the second law of thermodynamics is valid for living systems. Now Benjamin Sorkin at Tel Aviv University, Israel, and colleagues have considered the problem of entropy production in living systems by putting forward a generalization of the second law [2].

Dec 24, 2024

Darkness Unleashed: NASA’s Breakthrough Discoveries From the 2024 Solar Eclipse

Posted by in categories: innovation, transportation

The 2024 solar eclipse across North America spurred numerous NASA-supported research projects that observed the eclipse’s impact on the sun’s corona, Earth’s atmosphere, and radio communications.

Significant data were gathered from ground-based telescopes, aircraft, amateur radio transmissions, and student-launched high-altitude balloons.

Continue reading “Darkness Unleashed: NASA’s Breakthrough Discoveries From the 2024 Solar Eclipse” »

Dec 23, 2024

How a new fungi study could affect how we think about cognition

Posted by in categories: food, neuroscience

Editor’s note: This story has been updated to clarify the type of trees affected by Phanerochaete velutina.

A species of wood-eating fungus didn’t need a brain to pass a cognitive test with flying colors, and researchers say this first-of-its-kind discovery could have broader implications for understanding consciousness and intelligence in a variety of life forms.

A team of researchers at Japan’s Tohoku University, led by Yu Fukasawa, associate professor in the Graduate School of Agricultural Science, set out to determine whether fungi could recognize shapes. Their study, published in the journal Fungal Ecology in October, found evidence that these bottom feeders possess memory and decision-making abilities despite not having a central nervous system.

Dec 23, 2024

Astronomers have measured a black hole spinning at half the speed of light

Posted by in categories: cosmology, evolution

Astronomers have discovered a new way to study black holes, the mysterious cosmic entities that destroy anything in their path. By observing X-ray bursts from a star being torn apart by a black hole, researchers calculated the black hole’s spin rate for the first time using X-rays. The black hole was found spinning at nearly 50 percent of the speed of light. This research, published in Science, opens new possibilities for understanding black holes’ behavior and evolution.

The discovery dates back to November 2014, when astronomers observed a supermassive black hole in a galaxy 300 million light years away. This black hole ripped apart a star that had ventured too close, an event known as a tidal disruption flare. The flare generated intense bursts of X-rays that were visible from Earth. Since black holes themselves don’t produce many X-rays, researchers saw an opportunity to study this flare closely.

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