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New research combining experimental and computational approaches provides deeper insights into proton spin contributions from gluons.

Nuclear physicists have been tirelessly exploring the origins of proton spin. A novel approach, merging experimental data with cutting-edge calculations, has now illuminated the spin contributions from gluons—the particles that bind protons. This advancement also sets the stage for three-dimensional imaging of the proton structure.

Joseph Karpie, a postdoctoral associate at the Center for Theoretical and Computational Physics (Theory Center) at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility, led this groundbreaking research.

For decades, nuclear physicists have been working to uncover the mysterious origins of the proton’s spin. According to a new study, they seem to have finally made some progress.

By combining experimental data with state-of-the-art calculations, researchers have revealed a more detailed picture of the spin contributions from the very glue that holds protons together, paving the way for imaging the proton’s 3D structure.

The mystery of the proton’s spin began in 1987 when measurements revealed that the proton’s building blocks, its quarks, only provide about 30% of the proton’s total measured spin. This unexpected finding left physicists wondering about the sources of the remaining spin.

Swiss company Transmutex will use particle-accelerator technology to make uranium that produces less nuclear waste when used in fission reactions.

Researchers at the Princeton Plasma Physics Laboratory are harnessing artificial intelligence and machine learning to enhance fusion energy production, tackling the challenge of controlling plasma reactions. Their innovations include optimizing the design and operation of containment vessels and using AI to predict and manage instabilities, significantly improving the safety and efficiency of fusion reactions. This technology has been successfully applied in tokamak reactors, advancing the field towards viable commercial fusion energy. Credit: SciTechDaily.com.

The intricate dance of atoms fusing and releasing energy has fascinated scientists for decades. Now, human ingenuity and artificial intelligence are coming together at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) to solve one of humankind’s most pressing issues: generating clean, reliable energy from fusing plasma.

Unlike traditional computer code, machine learning — a type of artificially intelligent software — isn’t simply a list of instructions. Machine learning is software that can analyze data, infer relationships between features, learn from this new knowledge, and adapt. PPPL researchers believe this ability to learn and adapt could improve their control over fusion reactions in various ways. This includes perfecting the design of vessels surrounding the super-hot plasma, optimizing heating methods, and maintaining stable control of the reaction for increasingly long periods.

The Standard Model Lagrangian specifies all known particles that might come into being during a collision and how they might interact.

particle physics

By Matt von Hippel

Continue reading “The S-Matrix Is the Oracle Physicists Turn To in Times of Crisis” »

Diamonds are famously formed under high pressure and temperature, which is partly why they’re so valuable. But now, scientists have created diamonds in a lab under regular pressure in just 15 minutes.

Diamonds are basically just plain old carbon that’s been put under immense pressure and temperature, causing the atoms to crystallize into a particular structure. On Earth, the only place with the right natural conditions is deep in the mantle, hundreds of miles down. Only later are they brought closer to the surface, hitching rides in volcanic eruptions, which makes them pretty rare. Couple that with some of the most insidious marketing in history, and you’ve got a highly sought-after little rock.

Scientists have been growing diamonds in labs for decades, but it usually still needs those extreme conditions – almost 50,000 atmospheres of pressure, and temperatures of about 1,500 °C (2,732 °F). But a new technique has now produced diamonds under normal pressure levels and cooler temperatures.

Similar to optical vortex beams, terahertz (THz) vortex beams (TVBs) also carry orbital angular momentum (OAM). However, little research has been reported on the generation of TVBs. In this paper, based on the detour phase technique, we design a series of spintronic terahertz emitters with a helical Fresnel zone plate (STE-HFZP) to directly generate focused TVBs with topological charges (TCs) of l = ±1, ±2 and ±3, respectively. The STE-HFZP is a hybrid THz device composed of a terahertz emitter and a THz lens, and it has a high numerical aperture (NA), achieving subwavelength focal spots. Its focus properties are surveyed systemically through accurate simulations. This STE-HFZP can also generate focused TVBs with higher order TCs.

Researchers at the University of Hong Kong discovered Dirac spinons in the material YCu3-Br, providing evidence of a quantum spin liquid state and potentially advancing applications in quantum computing and high-temperature superconductivity.

Quasiparticles are fascinating entities that arise from collective behavior within materials and can be treated as a group of particles. Specifically, Dirac spinons are anticipated to exhibit unique characteristics similar to Dirac particles in high-energy physics and Dirac electrons in graphene and quantum moiré materials, such as a linear dispersion relation between energy and momentum. However, spin-½ charge-neutral quasiparticles had not been observed in quantum magnets until this work.

‘“To find Dirac spinons in quantum magnets has been the dream of generations of condensed matter physicists; now that we have seen the evidence of them, one can start to think about the countless potential applications of such highly entangled quantum material. Who knows, maybe one-day people will build quantum computers with it, just as people have been doing in the past half-century with silicon,’” said Professor Meng, HKU physicist and one of the corresponding authors of the paper.

Many of today’s quantum devices rely on collections of qubits, also called spins. These quantum bits have only two energy levels, the ‘0’ and the ‘1’. However, unlike classical bits, qubits can exist in superpositions, meaning they can simultaneously be in a combination of the ‘0’ and ‘1’ states. Spins in real devices also interact with light and vibrations known as bosons, greatly complicating calculations.

In a new publication in Physical Review Letters (“Fast quantum state preparation and bath dynamics using non-Gaussian variational Ansatz and quantum optimal control”), researchers in Amsterdam demonstrate a way to describe spin-boson systems and use this to efficiently configure quantum devices in a desired state.

Quantum devices use the quirky behaviour of quantum particles to perform tasks that go beyond what ‘classical’ machines can do, including quantum computing, simulation, quantum sensing, quantum communication and quantum metrology. These devices can take many forms, such as a collection of superconducting circuits, or a lattice of atoms or ions held in place by lasers or electric fields.