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Category: particle physics – Page 71

Faster, more stable plasma simulations help advance chip manufacturing

Plasma—the electrically charged fourth state of matter—is at the heart of many important industrial processes, including those used to make computer chips and coat materials.

Simulating those plasmas can be challenging, however, because millions of math operations must be performed for thousands of points in the simulation, many times per second. Even with the world’s fastest supercomputers, scientists have struggled to create a kinetic simulation—which considers individual particles—that is detailed and fast enough to help them improve those manufacturing processes.

Now, a new method offers improved stability and efficiency for kinetic simulations of what’s known as inductively coupled plasmas. The method was implemented in a developed as part of a private-public partnership between the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) and chip equipment maker Applied Materials Inc., which is already using the tool. Researchers from the University of Alberta, PPPL and Los Alamos National Laboratory contributed to the project.

Record-high Curie temperature achieved in ferromagnetic semiconductor

Ferromagnetic semiconductors (FMSs) combine the unique properties of semiconductors and magnetism, making them ideal candidates for developing spintronic devices that integrate both semiconductor and magnetic functionalities. However, one of the key challenges in FMSs has been achieving high Curie temperatures (TC) that enable their stable operation at room temperature.

Though previous studies achieved a TC of 420 K, which is higher than room temperature, it was insufficient for effectively operating the spin , highlighting the demand for an increase in TC among FMSs. This challenge has been featured among the 125 unsolved questions selected by the journal Science in 2005.

Materials such as (Ga, Mn)As exhibit low TC, limiting their practical use in spintronic devices. While adding Fe to narrow bandgap semiconductors like GaSb seemed promising, incorporating high concentrations of Fe while maintaining crystallinity proved difficult, restricting the attainable TC.

Overlooked electron property opens up new avenues for orbitronics

The orbital angular momentum of electrons has long been considered a minor physical phenomenon, suppressed in most crystals and largely overlooked. Scientists at Forschungszentrum Jülich have now discovered that in certain materials it is not only preserved but can even be actively controlled. This is due to a property of the crystal structure called chirality, which also influences many other processes in nature.

The discovery has the potential to lead to a new class of electronic components capable of transmitting information with exceptional robustness and energy efficiency.

From electronics to spintronics, and now to orbitronics: In classical electronics, it is primarily the charge of the electron that counts. In modern approaches such as and spintronics, the focus has shifted to the electron’s spin.

Researchers Used a One-Atom Quantum Computer to Simulate Real Molecules Over Time

We also simulated “open-system” dynamics, where the molecule interacts with its environment. This is typically a much harder problem for classical computers.

By injecting controlled noise into the ion’s environment, we replicated how real molecules lose energy. This showed environmental complexity can also be captured by quantum simulation.

On the Qualia Problem of Perception and the Measurement Problem of Quantum Theory

The qualia problem of perception is simply pointing out that the way we perceive the world is in terms of subjective qualities rather than numerical quantities. For example, we perceive the color of light in the things we see rather than the frequency of light wave vibrations or wavelengths, just as we perceive the quality of the sounds we hear rather than the frequency of sound wave vibrations. Another example is emotional qualities, like the perception of pleasure and pain and the perception of other emotional qualities, like the emotional qualities that color the perception of the emotional body feelings we perceive with emotional expressions of fear and desire. There is no possible way to understand the perception of these emotional qualities, just as there is no way to understand the perception of the colors we see or the qualities of the sounds we hear, in terms of the neuronal firing rates of neurons in the brain or other nervous systems. The frequency of wave vibrations and the neuronal firing rates of neurons are both examples of quantities. The problem is we do not perceive things in terms of numerical quantities, but rather in terms of subjective qualities.

All our physical theories are formulated in terms of numerical quantities, not in terms of subjective qualities. For example, in ordinary quantum theory or in quantum field theory, we speak of the frequency of light wave vibrations or the wavelength of a light wave in terms of a quantum particle called the photon. A photon or light wave is characterized by the numerical quantities of frequency and wavelength. When we formulate the nature of a light wave or photon in quantum theory in terms of Maxwell’s equations for the electromagnetic field, we can only describe numerical quantities. In ordinary quantum theory and quantum field theory, the electromagnetic field is the quantum wave-function, ψ(x, t), that specifies the quantum probability that the point particle called the photon can be measured at a position x in space at a moment t in time. That quantum probability is specified in terms of the frequency and wavelength that characterizes the wave-function for the photon.

AI enhances the Higgs boson’s ‘charm’

The Higgs boson, discovered at the Large Hadron Collider (LHC) in 2012, plays a central role in the Standard Model of particle physics, endowing elementary particles such as quarks with mass through its interactions. The Higgs boson’s interaction with the heaviest “third-generation” quarks—top and bottom quarks—has been observed and found to be in line with the Standard Model.

But probing its interactions with lighter “second-generation” quarks, such as the quark, and the lightest “first-generation” quarks—the up and down quarks that make up the building blocks of atomic nuclei—remains a formidable challenge, leaving unanswered the question of whether or not the Higgs boson is responsible for generating the masses of the quarks that make up ordinary matter.

Researchers study the Higgs boson’s interactions by looking at how the particle decays into—or is produced with—other particles in high-energy proton–proton collisions at the LHC.

Invisible currents at the edge: Study shows how magnetic particles reveal hidden rule of nature

If you’ve ever watched a flock of birds move in perfect unison or seen ripples travel across a pond, you’ve witnessed nature’s remarkable ability to coordinate motion. Recently, a team of scientists and engineers at Rice University discovered a similar phenomenon on a microscopic scale, where tiny magnetic particles driven by rotating fields spontaneously move along the edges of clusters driven by invisible “edge currents” that follow the rules of an unexpected branch of physics.

The research is published in the journal Physical Review Research.

“When I saw the initial data—with streams of particles moving faster along the edges than in the middle—I said ‘these are edge flows’ and we got to work exploring this,” said corresponding author Evelyn Tang, assistant professor of physics and astronomy. “What’s very exciting is that we can explain their emergence using ideas from topological physics, a field that became prominent due to quantum computers and .”

Researchers uncover a mechanism enabling glasses to self-regulate their brittleness

Materials with self-adaptive mechanical responses have long been sought after in material science. Using computer simulations, researchers at the Tata Institute of Fundamental Research (TIFR), Hyderabad, now show how such adaptive behavior can emerge in active glasses, which are widely used as models for biological tissues.

The findings, published in the journal Nature Physics, provide new insights—ranging from how cells might regulate their glassiness to aiding in the design of new metamaterials.

Glasses (or amorphous solids) are materials whose components lack any particular ordering. Contrast this with a crystal, where atoms are arranged in neat, repeating patterns on a well-defined lattice. While crystals are ordered and nearly perfect, amorphous materials are defined by their disorder.

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