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Category: particle physics – Page 2

From smartphones and TVs to credit cards, technologies that manipulate light are deeply embedded in our daily lives, many of which are based on holography. However, conventional holographic technologies have faced limitations, particularly in displaying multiple images on a single screen and in maintaining high-resolution image quality.

Recently, a research team led by Professor Junsuk Rho at POSTECH (Pohang University of Science and Technology) has developed a groundbreaking metasurface technology that can display up to 36 on a surface thinner than a . This research has been published in Advanced Science.

This achievement is driven by a special nanostructure known as a metasurface. Hundreds of times thinner than a human hair, the metasurface is capable of precisely manipulating light as it passes through. The team fabricated nanometer-scale pillars using silicon nitride, a material known for its robustness and excellent optical transparency. These pillars, referred to as meta-atoms, allow for fine control of light on the metasurface.

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The precise measurement of states in atomic and molecular systems can help to validate fundamental physics theories and their predictions. Among the various platforms that can help to validate theoretical predictions are so-called diatomic molecular hydrogen ions (MHI), molecular ions that consist of two hydrogen nuclei (i.e., protons or their isotopes) and a single electron.

Compared to , these molecular ions have a more complex internal structure, as they contain two nuclei instead of one. Even when they are in their lowest possible electronic energy level (i.e., the electron’s ground state), these two nuclei can still rotate and vibrate, producing a wide range of rovibrational states.

Researchers at the Max Planck Institute for Nuclear Physics recently introduced a new method to precisely control and non-destructively measure the rovibrational ground state of a single molecular hydrogen ion in a Penning trap (i.e., a device that confines charged particles using static electric and magnetic fields).

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A team of physicists has embarked on a journey where few others have gone: into the glue that binds atomic nuclei. The resultant measurement, which was extracted from experimental data taken at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility, is the first of its kind and will help physicists image particles called gluons.

The paper revealing the results is published and featured as an editor’s suggestion in Physical Review Letters.

Gluons mediate the strong force that “glues” together quarks, another type of subatomic particle, to form the protons and neutrons situated at the center of atoms of ordinary matter. While previous measurements have allowed researchers to learn about the distribution of gluons in solitary protons or neutrons, they know less about how gluons behave inside protons or neutrons bound in nuclei.

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Juan Casado Cordón, Professor of Physical Chemistry at the University of Malaga, considers graphene—an infinite layer of carbon atoms—as one of the greatest discoveries of the last 20 years due to its “unique properties” such as high electrical and thermal conductivity or its great flexibility and, also, resistance. Qualities that become exceptional, he explains, with a recently found evolution consisting in joining two layers of this material—bilayer graphene.

Researchers from the University of Malaga, led by Casado Cordón, and from the Complutense University, under the coordination of Professor Nazario Martín, have taken a step further and created an unprecedented molecular model of that is capable of controlling rotation, which in turn allows controlling conductivity and achieving “potentially spectacular semiconducting properties.”

The result is a new model molecule of bilayer graphene. “By designing covalently bound molecular nanographenes we can simulate the search for the magic angle between graphene-like sheets, which is where semiconductivity is achieved, a key property in, for example, the construction of transistors, the basic units of computers,” explains this scientist from the Faculty of Science. This finding has been published in Nature Chemistry.

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A research team has discovered how to make a promising energy-harvesting material much more efficient—without relying on rare or expensive elements. The material, called β-Zn4Sb3, is a tellurium-free thermoelectric compound that can convert waste heat into electricity.

In their study published in Advanced Science, scientists used advanced neutron scattering techniques to peek inside the crystal and found something surprising: tiny heat vibrations (called phonons) were being disrupted by “rattling” atoms inside the structure. This phenomenon, known as avoided crossing, dramatically slowed down how heat travels through the material.

Thanks to this effect, the material’s dropped to extremely low levels—great news for . Even better, the researchers found that the single-crystal version of this material also conducts electricity better than its polycrystalline counterpart, reaching a high power conversion efficiency of 1.4%.

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The COVID-19 pandemic increased public awareness of the importance of mask use for personal protection. However, when the mesh size of mask fabrics is small enough to capture viruses, which are usually around one hundred nanometers in size, the fabric typically also restricts air flow, resulting in user discomfort. Researchers from Japan have now developed a new filter material that effectively captures nanoparticles, although further improvements are needed to make it suitable for comfortable mask use.

In a study published this month in Materials Advances, researchers from the Institute of Industrial Science at the University of Tokyo have developed a filter capable of capturing nanoparticles such as viruses. While the filter demonstrates high filtration efficiency, its airflow resistance is currently higher than the standards required for face masks, indicating that additional development is necessary before it can be used for personal protective equipment.

The filter is constructed from nanosheets consisting of an ordered mesh composed of porphyrins, which are flat, ring-shaped molecules with a central hole. The in the porphyrin molecules are suitably sized to allow the easy passage of the small gas molecules in air while blocking the movement of larger particles, such as viruses. The nanosheets are then supported on a fabric modified with nanofibers containing pores of several hundred nanometers to form the filter.

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