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Category: particle physics – Page 51

Physicists capture elusive plasma instability in unprecedented detail

For the first time, scientists have ‘photographed’ a rare plasma instability, where high-energy electron beams form into spaghetti-like filaments.

A new study, published in Physical Review Letters, outlines how a high-intensity infrared laser was used to generate filamentation instability—a phenomenon that affects applications in -based particle accelerators and fusion energy methods.

Plasma is a super-hot mixture of charged particles, such as ions and electrons, which can conduct electricity and are influenced by magnetic fields. Instabilities in plasmas can occur because the flow of particles in one direction or within a specific region can be different from the rest, causing some particles to group up into thin spaghetti-like filaments.

Can a Particle Be Neither Matter Nor Force?

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All particles belong to two large groups: fermions like protons and electrons make everything we consider “matter”, while bosons like photons and gluons transmit the fundamental forces. And that about covers the universe: matter moving through space and time under the action of forces. But what if we could create particles in between these two possibilities. Physics says these neither matter nor force anyons can exist, and they may have some pretty incredible uses. They’re called anyons.

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Physicists “Slow Down Light” to Just 61 Kilometers per Hour Using Ultracold Quantum Matter

The speed of light is often regarded as the ultimate cosmic speed limit, but researchers have now managed to slow it down dramatically—to just 61 kilometers per hour. This was achieved by using a Bose-Einstein condensate (BEC), a peculiar quantum state of matter that allows light to be slowed or even stopped entirely. This discovery, which builds on decades of research, has implications for quantum physics, computing, and information storage.

The Quantum Jelly Effect In everyday conditions, light moves at 299,792,458 meters per second in a vacuum, and its speed decreases slightly when passing through materials like glass or water. However, these reductions are relatively small. In contrast, when light travels through a Bose-Einstein condensate, it can be slowed to a near standstill.

A Bose-Einstein condensate is an exotic state of matter, first predicted by Albert Einstein and Satyendra Nath Bose, that occurs when a gas is cooled to temperatures just above absolute zero. Under these conditions, the atoms behave as a single quantum entity, exhibiting superfluidity and interacting with light in ways not seen in ordinary materials.

Sneaky clocks: Uncovering Einstein’s relativity in an interacting atomic playground

For over a century, physicists have grappled with one of the most profound questions in science: How do the rules of quantum mechanics, which govern the smallest particles, fit with the laws of general relativity, which describe the universe on the largest scales?

The optical lattice clock, one of the most precise timekeeping devices, is becoming a powerful tool used to tackle this great challenge. Within an optical lattice clock, atoms are trapped in a “lattice” potential formed by laser beams and are manipulated with precise control of quantum coherence and interactions governed by .

Simultaneously, according to Einstein’s laws of general relativity, time moves slower in stronger gravitational fields. This effect, known as gravitational redshift, leads to a tiny shift of atoms’ internal energy levels depending on their position in gravitational fields, causing their “ticking”—the oscillations that define time in optical lattice clocks—to change.

Quantum algorithm excels at finding local minima of many-body systems

Many physicists and engineers have recently been trying to demonstrate the potential of quantum computers for tackling some problems that are particularly demanding and are difficult to solve for classical computers. A task that has been found to be challenging for both quantum and classical computers is finding the ground state (i.e., lowest possible energy state) of systems with multiple interacting quantum particles, called quantum many-body systems.

When one of these systems is placed in a thermal bath (i.e., an environment with a fixed temperature that interacts with the systems), it is known to cool down without always reaching its . In some instances, a can get trapped at a so-called local minimum; a state in which its energy is lower than other neighboring states but not at the lowest possible level.

Researchers at California Institute of Technology and the AWS Center for Quantum Computing recently showed that while finding the local minimum for a system is difficult for classical computers, it could be far easier for quantum computers.

Nitrogen’s dominant role in global organic aerosol absorption revealed

A collaborative research team has introduced a nitrogen-centric framework that explains the light-absorbing effects of atmospheric organic aerosols. Published in Science, this study reveals that nitrogen-containing compounds play a dominant role in the absorption of sunlight by atmospheric organic aerosols worldwide. This discovery signifies a major step towards improving climate models and developing more targeted strategies to mitigate the climate impact of airborne particles.

Atmospheric organic aerosols influence climate by absorbing and scattering sunlight, particularly within the near-ultraviolet to visible range. Due to their complex composition and continuous chemical transformation in the atmosphere, accurately assessing their climate effects has remained a challenge.

The study was jointly led by Prof. Fu Tzung-May, Professor of the School of Environmental Science and Engineering at Southern University of Science and Technology (SUSTech) and National Center for Applied Mathematics Shenzhen (NCAMS), and Prof. Yu Jianzhen, Chair Professor of the Department of Chemistry and the Division of Environment and Sustainability at Hong Kong University of Science and Technology (HKUST).

Controlling electrons in molecules at ultrafast timescales with tailor-made terahertz light pulses

Scientists at Yokohama National University, in collaboration with RIKEN and other institutions in Japan and Korea, have made an important discovery about how electrons move and behave in molecules. This discovery could potentially lead to advances in electronics, energy transfer, and chemical reactions.

Published in the Science, their study reveals a new way to control the distribution of electrons in molecules using very fast phase-controlled pulses of light in the .

Atoms and molecules contain negatively charged electrons that usually stay in specific energy levels, like layers, around the positively charged nucleus. The way these electrons are arranged in the molecule is key to how the molecule behaves.

Laser light made into a supersolid for the first time

A small international team of nanotechnologists, engineers and physicists has developed a way to force laser light into becoming a supersolid. Their paper is published in the journal Nature. The editors at Nature have published a Research Briefing in the same issue summarizing the work.

Supersolids are entities that exist only in the quantum world, and, up until now, they have all been made using . Prior research has shown that they have zero viscosity and are formed in crystal-like structures similar to the way atoms are arranged in salt crystals.

Because of their nature, supersolids have been created in extremely cold environments where the can be seen. Notably, one of the team members on this new effort was part of the team that demonstrated more than a decade ago that light could become a fluid under the right set of circumstances.

Neutrinos could tell us about the inside of the sun and establish density structure

Neutrinos generated through solar fusion reactions travel effortlessly through the sun’s dense core. Each specific fusion process creates neutrinos with distinctive signatures, potentially providing a method to examine the sun’s internal structure. Multiple neutrino detection observatories on Earth are now capturing these solar particles, which can be analyzed alongside reactor-produced neutrinos with the data eventually enabling researchers to construct a detailed map of the interior of the sun.

The sun is a massive sphere of hot plasma at the center of our solar system and provides the light and heat to make life on Earth possible. Composed mostly of hydrogen and helium, it generates energy through , converting hydrogen into helium in its core. This process releases an enormous amount of energy which we perceive as heat and light.

The sun’s surface, or photosphere, is around 5,500°C, while its core reaches over 15 million°C. It influences everything from our climate to space weather, sending out and occasional bursts of radiation known as . As an average middle-aged star, the sun is about 4.6 billion years old and will (hopefully) continue burning for another 5 billion years before evolving into a red giant and eventually becoming a white dwarf.