Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: particle physics – Page 15

A new route to electrically controlled helimagnetic structures

Advanced magnetic memory and spintronic devices rely on the ability to control magnetic states using electricity. Today, such technologies work by manipulating relatively simple magnetic structures found in ferromagnets, where all the magnetic moments point the same way. However, researchers are becoming increasingly interested in controlling more complex magnetic systems because these could offer higher information density and improved efficiency.

Helimagnets are a prime example of such systems. In these materials, the magnetic moments form spiral or helical patterns that wind through the material. The direction in which these magnetic patterns propagate plays an important role in determining the material’s electrical and magnetic behavior.

However, researchers had not established a reliable way to reversibly control the orientation of helical magnetic structures using an electric current, and current-driven techniques developed for ferromagnets do not directly carry over to helimagnetic systems.

AI identifies new particle models that may explain neutrinos’ tiny mass

Physicists at the University of California, Irvine, have developed an artificial intelligence system that can autonomously design theoretical physics models, a task traditionally carried out by human theorists. The approach allows researchers to explore large, uncharted areas of particle physics theory, helping identify promising new explanations for the behavior of neutrinos.

The system is called Autonomous Model Builder (AMBer), and was developed by a research team led by UC Irvine doctoral candidates Victoria Knapp-Pérez and Jake Rudolph in the Department of Physics and Astronomy. The work is published in Communications Physics.

AMBer uses reinforcement learning, a form of artificial intelligence that learns through trial and error rather than by following predefined instructions. As it explores possible particle physics theories, the system evaluates its own choices and improves over time.

Programmable light simulates quantum matter across 300 processes without bigger circuits

A team of researchers at the University of Ottawa and its Nexus for Quantum Technologies Institute, in collaboration with researchers from Federico II University in Italy, has developed a programmable quantum simulator that shapes a beam of light to replicate how particles move through complex materials, avoiding the need for ever-larger electronic hardware.

Check your ingredients’: A new blueprint for using Fermi’s ‘Golden Rule

Underpinning much of modern technology, from smartphones to scanning tunneling microscopes to particle colliders, is Fermi’s Golden Rule. Named for 20th-century Italian American physicist Enrico Fermi (but actually discovered by British physicist Paul Dirac), the rule is a formula that connects what can be measured in an experiment—such as how fast atoms “jump” between energy states—to the microscopic properties of a quantum mechanical system. The formula is taught in every undergraduate quantum physics class.

Yet scientists sometimes misapply it. They either misjudge the conditions under which the formula works, or they miss the “window” for its use. A “user manual” for Fermi’s Golden Rule would be a boon to researchers, says Yale physicist Nir Navon—and now he and his lab partners have provided one.

“We put one of the most famous formulas in all of quantum mechanics to the test, and found where it works and where it fails, including ways that many physicists weren’t fully aware of,” said Navon, an associate professor of physics in Yale’s Faculty of Arts and Sciences and senior author of a new study published in the journal Nature Physics. “We’re telling everyone who uses it to take a breath first and check their ingredients.”

China Built a Working CPU With Transistors Just 3 Atoms Thick

Recommended RISC-V development and chip-inspection tools:

Freenove Raspberry Pi Pico 2 W — Dual ARM and RISC-V Microcontroller:
https://amzn.to/4eOMIlu.

Seeed Studio XIAO ESP32C3 — Compact 32-Bit RISC-V Development Board:
https://amzn.to/4v1d1Lh.

Raspberry Pi Pico 2 WH Basic Kit — Dual ARM and RISC-V Architecture:
https://amzn.to/4euVwOu.

Elikliv 1000X LCD Digital Microscope for Electronics Inspection:
https://amzn.to/4xY2hA7

Disclosure: These are affiliate links. I may earn a commission at no extra cost to you. As an Amazon Associate I earn from qualifying purchases.

Continue reading “China Built a Working CPU With Transistors Just 3 Atoms Thick” | >

Researchers develop a new way to build molecular ‘ladders’ for organic electronics

Ladder-type oligothiophenes are an important class of sulfur-containing π-conjugated molecules. Because their fused, ladder-like structures can support efficient electronic interactions, they are widely studied as core motifs for organic semiconductors, organic field-effect transistors, flexible electronics and related molecular materials.

In molecular electronics, however, simply connecting rings together is not enough. The electronic properties of these molecules depend strongly on how the thiophene rings are fused and how sulfur atoms are oriented along the molecular framework. Some arrangements produce highly conjugated systems, while others introduce cross-conjugated segments that can alter the band gap and molecular packing.

Although interest in such mixed conjugated/cross-conjugated molecular systems is growing, a general method for systematically constructing regioisomeric ladder-type oligothiophenes with precise control over thiophene ring orientation has not been well established.

A Widening Anomaly Strains the Standard Model

Does a new measurement of a rare decay of the neutral B meson portend new physics?

In particle physics, ten years is a long time to sit with a puzzle. Since 2013, measurements of a rare decay—a neutral B meson (B0) transforming into an excited kaon (K*0) and a muon–antimuon pair (µ+µ –)—have stubbornly refused to match the predictions of the standard model, the theory that describes all known particles and forces [1]. Small enough to be dismissed at first as a statistical fluctuation, the pattern of discrepancies has grown with each new dataset into one of the most tantalizing hints of new physics in experimental particle physics. Now the LHCb Collaboration at CERN in Switzerland has published its most comprehensive analysis of the decay to date [2]. The result is clear: The anomaly persists. Encouragingly, the theoretical and experimental tools to understand it have never been sharper.

Within the mathematical framework of the standard model, the decay in question, B0 → K*0µ+µ–, can occur only through so-called higher-order electroweak loop diagrams in which a bottom, or b, quark transforms into a strange, or s, quark [3]. As a result, the decay is extraordinarily rare. In every million B-meson decays of all kinds, you can expect to find only one. That rarity makes the decay valuable: It could bear measurable imprints of particles beyond the standard model that contribute to the same loop processes but have so far escaped detection because they are too heavy.

Catching hydrogen in the act: Tracking the absorption process over time

If you’re looking for hydrogen on the elemental chart, it won’t take you long to find it. It is right there at the beginning, the lightest possible material. One electron, one proton, one neutron. Simple, minimalistic, the Marie Kondo of the elemental chart, but with enormous potential in terms of possible technological applications.

A very prominent example interests every single one of us: Let’s look into the daytime sky.

If we think of the sun as a furnace, then hydrogen atoms are the coal ingots.

Why some glasses break suddenly while others deform smoothly

If a liquid is cooled slowly to its freezing point, it becomes a crystal in which the constituent particles are arranged in an ordered pattern. In contrast, when the liquid is cooled very quickly, the particles are unable to arrange themselves in an ordered fashion, and it becomes glass. Glassy materials are all around us in everyday life. Common examples include window glass, certain metal alloys, polymers, foams, gels and even soft materials like emulsions and colloids.

These materials can behave very differently when an external force is applied to them, such as bending, stretching or compressing. Some materials change shape slowly and smoothly under strain (this property is called ductility). Some materials may resist deformation at first but then suddenly break or crack without warning (this property is called brittleness). Whether a material bends or breaks determines how safely and reliably it can be used in everyday objects and engineering applications.

Scientists broadly classify glasses into two types: strong and fragile glasses.

/* */