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Category: particle physics – Page 4

Multi-scale turbulence observations reveal new plasma confinement performance mechanism

Around the world, research is advancing to efficiently confine fusion plasma and harness its immense energy for power generation. However, it is known that turbulence occurring at various scales within the plasma causes the release of plasma energy and constituent particles, degrading the confinement performance.

Elucidating this physical phenomenon and suppressing performance degradation is critically important. Particularly in the high-temperature plasma experiments currently conducted worldwide, micro-scale (just a few centimeters) turbulent eddies forming at various locations within the plasma significantly impact this confinement performance degradation.

While it was known that suppressing this micro-scale could improve performance to a certain extent, the reason why further improvement could not be achieved remained unclear. In addition, theoretical simulation studies predict that in future fusion power reactors, turbulence smaller than micro-scale will interact and exert influence.

Ireland officially joins CERN as associate member state

Ireland has officially joined the European Organisation for Nuclear Research (CERN) as an associate member state.

CERN is an intergovernmental organisation that operates the largest particle physics laboratory in the world on the Franco-Swiss border, just outside Geneva.

The main focus of activity in CERN is the Large Hadron Collider (LHC), a 27km underground ring in which protons are accelerated and collided into one another.

Quantum simulations that once needed supercomputers now run on laptops

UB physicists have upgraded an old quantum shortcut, allowing ordinary laptops to solve problems that once needed supercomputers. A team at the University at Buffalo has made it possible to simulate complex quantum systems without needing a supercomputer. By expanding the truncated Wigner approximation, they’ve created an accessible, efficient way to model real-world quantum behavior. Their method translates dense equations into a ready-to-use format that runs on ordinary computers. It could transform how physicists explore quantum phenomena.

Picture diving deep into the quantum realm, where unimaginably small particles can exist and interact in more than a trillion possible ways at the same time.

It’s as complex as it sounds. To understand these mind-bending systems and their countless configurations, physicists usually turn to powerful supercomputers or artificial intelligence for help.

Dual torque from electron spins drives magnetic domain wall displacement

A research team has taken a major step forward in the field of spintronics, a technology that uses not only the charge but also the spin of electrons to create faster, smarter, and more energy-efficient electronic devices. Their discovery could pave the way for the next generation of memory chips that combine high speed with low power consumption.

In spintronic memory, information is stored using tiny magnetic regions called . A magnetic domain with its magnetic moments pointing upward represents a “1,” while one pointing downward represents a “0.” Data can be read or written by shifting these domains with an .

The boundaries between them, known as domain walls, play a crucial role, as moving domains means moving these walls. Achieving fast and efficient domain wall motion is essential for developing advanced memories such as magnetic shift registers and three-terminal magnetic random access memories (MRAM).

Graphene partially screens van der Waals interactions depending on layer thickness, study reveals

Two-dimensional (2D) materials, which are only a few atoms thick, are known to exhibit unique electrical, mechanical and optical properties, which differ considerably from the properties of bulk materials. Some recent studies have also been probing these materials’ “transparency” to intermolecular interactions, such as van der Waals (vdW) forces—weak forces arising from fluctuating electrical charges, which prompt the attraction between molecules or surfaces.

Determining the extent to which these forces are screened by atomically thin materials could have important implications for the development of various technologies based on 2D materials.

Researchers at Peking University, Nanjing University of Aeronautics and Astronautics and Tsinghua University recently set out to shed light on whether 2D graphene systems fully transmit, partially screen or block vdW interactions.

Magnetized plasmas offer a new handle on nanomaterial design

Imagine a cloud that shines like a neon sign, but instead of raindrops, it contains countless microscopic dust grains floating in midair. This is a dusty plasma, a bizarre state of matter found both in deep space and in the laboratory.

In a new study, published this week in Physical Review E, Auburn University physicists report that even can reshape how these dusty plasmas behave—slowing down or speeding up the growth of nanoparticles suspended inside. Their experiments show that when a magnetic field nudges into spiraling paths, the entire plasma reorganizes, changing how particles charge and grow.

“Dusty plasmas are like in a vacuum box,” said Bhavesh Ramkorun, lead author of the study. “We found that by introducing magnetic fields, we could make these particles grow faster or slower, and the ended up with very different sizes and lifetimes.”

Phosphorus chains display true 1D electronic properties on a silver substrate

For the first time, a team at BESSY II has succeeded in demonstrating the one-dimensional electronic properties of a material through a highly refined experimental process.

The samples consisted of short chains of phosphorus atoms that self-organize at specific angles on a silver substrate. Through sophisticated analysis, the team was able to disentangle the contributions of these differently aligned chains. This revealed that the electronic properties of each chain are indeed one-dimensional. Calculations predict an exciting phase transition to be expected as soon as these chains are more closely packed. While material consisting of individual chains with longer distances is semiconducting, a very dense chain structure would be metallic.

The work is published in the journal Small Structures.

Quasicrystals Grow Smoothly Around Obstacles

Large-scale obstacles to crystal growth can throw the whole lattice off kilter, but quasicrystals can accommodate them without losing their atomic-scale order.

When a growing crystal encounters an obstacle, the orderly array of atoms may have to adjust in ways that create lattice defects or large-scale rearrangements. But a research team has found through experiments that peculiar materials called quasicrystals can take such disruptions in stride [1] The quasicrystalline lattice, which is orderly but not periodic, can accommodate obstacles without sacrificing its order, thanks to a type of rearrangement unique to quasicrystals. The work suggests the possibility of making quasicrystalline metal alloys that are more durable than conventional alloys.

Quasicrystals, discovered in 1984, are typically compounds composed of metals such as aluminum, nickel, and manganese. X-ray diffraction seems to show that their atomic lattices have symmetries that aren’t permitted in conventional crystals, such as pentagonal or decagonal symmetry. But these symmetries can exist in small regions because quasicrystals are not conventional crystals—you can’t shift the atomic lattice in space and then superimpose it exactly on the original lattice.

Vortices in ultralight dark matter halos could reveal new clues to cosmic structure

The nature of dark matter remains one of the greatest mysteries in cosmology. Within the standard framework of non-collisional cold dark matter (CDM), various models are considered: WIMPs (Weakly Interacting Massive Particles, with masses of around 100 GeV/c2), primordial black holes, and ultralight axion-like particles (mass of 10-22 to 1 eV/c2). In the latter case, dark matter behaves like a wave, described by a Schrödinger equation, rather than as a collection of point particles. This generates specific behaviors at small scales, while following standard dynamics (CDM) at large scales.

Philippe Brax and Patrick Valageas, researchers at the Institute of Theoretical Physics, studied models of ultralight cold dark matter with repulsive self-interactions, whose dynamics are described by a non-linear variant of the Schrödinger equation, known as the Gross-Pitaevskii equation, also encountered in the physics of superfluids and Bose-Einstein condensates. In their work, the authors follow the formation and dynamics of particular structures, called “vortices” (whirlpools) and “solitons” (cores in hydrostatic equilibrium), within halos of rotating ultralight dark matter.

The papers are published in the journal Physical Review D.

Diamond probe measures ultrafast electric fields with femtosecond precision

Researchers at University of Tsukuba have successfully measured electric fields near the surfaces of two-dimensional layered materials with femtosecond temporal and nanometer spatial resolution. They employed a diamond containing a nitrogen-vacancy center—a lattice defect—as a probe within an atomic force microscope, enabling atomic-scale spatial precision.

When nitrogen is incorporated as an impurity in a , the absence of a neighboring carbon atom forms a nitrogen-vacancy (NV) center. Applying an to diamond containing NV centers modifies its , a phenomenon known as the electro-optic (EO) effect. Notably, this effect has not been observed in pure diamond alone.

In previous work, the research team used a to detect lattice vibrations in diamond with high sensitivity by measuring the EO effect in high-purity diamond containing NV centers. These results demonstrated that diamond can act as an ultrafast EO crystal and serve as a probe—termed a diamond NV probe—for measuring electric fields.

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