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Category: particle physics – Page 96

What Are Electrons Made Of? Unveiling the Mystery!

Electrons, those fundamental particles that orbit atomic nuclei, are central to electromagnetism and chemical processes. Ever since their discovery, scientists have pondered over what electrons are made of and their basic structure. While particles such as protons and neutrons have shown internal complexity, electrons appear impenetrable to such analysis. So, what constitutes an electron? Are they truly indivisible, or do they hide smaller components within?

Speaking of the atom, the term “indivisible” now seems outdated, especially with modern scientific understanding. The notion that atoms are the most fundamental units of matter dates back to Democritus over 2,000 years ago. However, as centuries passed and scientific discoveries unfolded, it became clear that atoms were not the ultimate particles of matter. Indeed, advancements in physics have shown that atoms are made up of even smaller particles: protons, neutrons, and electrons. While protons and neutrons can be broken down into quarks, the question remains for electrons: are they also made of smaller components, or are they indivisible?

Since their discovery over 125 years ago, electrons have challenged the logic of decomposition. No experiment has yet detected any more complex internal structure, even during high-energy collisions aimed at probing deeper levels of matter. Electrons thus seem to defy the notion of being made up of smaller particles. They are currently regarded as fundamental particles within the standard model of particle physics, meaning they are entities that cannot be divided further.

Researchers reveal full-gray optical trap in structured light

A research group led by Prof. Yao Baoli and Dr. Xu Xiaohao from Xi’an Institute of Optics and Precision Mechanics (XIOPM) of the Chinese Academy of Sciences have revealed a full-gray optical trap in structured light, which is able to capture nanoparticles but appears at the region where the intensity is neither maximized nor minimized. The study is published in Physical Review A.

The optical trap is one of the greatest findings in optics and photonics. Since the pioneering work by Arthur Ashkin in the 1970s, the has been employed in a broad range of applications in life sciences, physics, and engineering. Akin to its thermal and acoustic counterparts, this trap is typically either bright or dark, located at the field intensity maxima or minima.

In this study, researchers developed a high-order multipole model for gradient forces based on multipole expansion theory. Through immersing the Si particles in the structured light with a petal-shaped field, they found that the high-order multipole gradient forces can trap Si particles at the optical intensity, which is neither maximized nor minimized.

MIT’s light-activated antiferromagnetic memory could replace today’s ferromagnets

The research team, led by physics professor Nuh Gedik, concentrated on a material called FePS₃, a type of antiferromagnet that transitions to a non-magnetic state at around −247°F. They hypothesized that precisely exciting the vibrations of FePS₃’s atoms with lasers could disrupt its typical antiferromagnetic alignment and induce a new magnetic state.

In conventional magnets (ferromagnets), all atomic spins align in the same direction, making their magnetic field easy to control. In contrast, antiferromagnets have a more complex up-down-up-down spin pattern that cancels out, resulting in zero net magnetization. While this property makes antiferromagnets highly resistant to stray magnetic influences – an advantage for secure data storage – it also creates challenges in intentionally switching them between “0” and “1” states for computing.

Gedik’s innovative laser-driven approach seeks to overcome this obstacle, potentially unlocking antiferromagnets for future high-performance memory and computational technologies.

Cosmic Origins of Complex Organic Molecules Unveiled

Recent studies indicate that the cosmos is rich in complex organic molecules, essential components for understanding the origins of life. The European Space Agency’s Rosetta probe, which examined the comet 67P/Churyumov-Gerasimenko over a two-year mission, provided significant insights into the presence of these molecules in space.

Organic molecules, defined as compounds containing carbon, are abundant not only on Earth but also throughout the universe. Their structure allows carbon atoms to create stable chains, forming the backbone of various biological compounds. The findings from Rosetta have transformed our understanding of where these building blocks of life might originate.

During its mission, Rosetta detected over 44 distinct organic molecules, including glycine, a fundamental amino acid. Moreover, recent analyses of the data identified dimethyl sulfide, a gas associated exclusively with biological processes on Earth, suggesting that the conditions for life may be more widespread than previously assumed.

Grapes double sensor magnetic power in an epic quantum breakthrough

Grape pairs enhance magnetic fields, advancing compact, cost-effective quantum sensor technology.

In interesting research, insights from ordinary supermarket grapes led researchers to boost quantum sensor performance.

The study reveals that grape pairs generate localized magnetic field hotspots for microwaves, aiding compact and cost-effective quantum sensor development.

The Macquarie University team’s work in Sydney builds on viral videos of grapes producing plasma, glowing charged particles, in microwave ovens.

Machine learning speeds up prediction of materials’ spectral properties

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.

High-quality nanodiamonds offer new bioimaging and quantum sensing potential

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.

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

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.

Seeking Signatures of High-Energy Vortex States

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.