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Category: particle physics – Page 20

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.

Bright Streak Appears Over US During Aurora Storm, Mystifying Skywatchers

On the night of Saturday 17 May, skywatchers across the US as far south as New Mexico were treated to a peculiar sight: a brilliant stream of whitish light, stretching across the sky.

That was a night for auroral activity, as Earth’s magnetic field was buffeted by an influx of particles ejected from the Sun several days earlier. Initially, explanations favored STEVE, the name given to the white-mauve streaks of light emitted by rivers of charged particles flowing through Earth’s ionosphere.

STEVE is not an aurora, but, like the auroral displays it often appears alongside, is also a product of space weather.

The US test fired its most powerful laser ever

Accomplishing this and other experimental feats does require some safeguards. ZEUS includes optical devices known as diffraction gratings that stretch out the initial infrared pulse over time. This ensures the initial power doesn’t get so intense that it begins tearing apart the air around it.

Another goal is to ultimately create beams of electrons with energies similar to those found in particle accelerators hundreds of feet longer than ZEUS at a fraction of both its size and operating costs. At only $16 million to construct, the University of Michigan previously described the machine as a “bargain.”

Years of construction, calibration, and expertise is showcased in an astoundingly short amount of time. ZEUS’ 2 petawatt firing lasted just 25 quintillionths of a second. But future experiments will make the most of these moments.

Chandra diagnoses cause of fracture in galactic ‘bone’

Astronomers have discovered a likely explanation for a fracture in a huge cosmic “bone” in the Milky Way galaxy, using NASA’s Chandra X-ray Observatory and radio telescopes.

The bone appears to have been struck by a fast-moving, rapidly spinning neutron star, or a pulsar. Neutron stars are the densest known stars and form from the collapse and explosion of massive stars. They often receive a powerful kick from these explosions, sending them away from the explosion’s location at high speeds.

Enormous structures resembling bones or snakes are found near the center of the galaxy. These elongated formations are seen in radio waves and are threaded by magnetic fields running parallel to them. The radio waves are caused by energized particles spiraling along the magnetic fields.

CASIMIR EFFECT II Creator Of Mysterious Force Carrier

CASIMIR EFFECT @SEVENTHQUANTUMACADEMY

This video will tell you the mysterious creator of force carrier particle particularly Graviton and then chronologically gluon, photon and boson. You will see delving into the string theory and quantum physics and dimensional physics that how this force was first created immediately after the first quantum vacuum fluctuation and the creation of Planck’s length and hence the Planck’s world. You will observe with tremendous astonishment that it is telling some other stories regarding birth of invisible universe which is the predecessor of the visible third dimensional universe we can see today. So to delve into this mysterious world, watch the full video with concentration and to get more subscribe SEVENTH QUANTUM ACADEMY and tap the bell icon to get notified when the new video gets published.

An ‘invisible order’ in glass shapes vibrations in the terahertz frequency range

Although glasses exhibit disordered atomic structures, X-ray and neutron scattering reveal a subtle periodicity. Researchers at the University of Tsukuba have demonstrated that this hidden periodicity—referred to as “invisible order”—plays a critical role in determining vibrational fluctuations in the terahertz (THz) frequency range, which significantly influence the physical properties of glass.

The research is published in the journal Scientific Reports.

At first glance, glass appears to be a random network of atoms. However, X-ray and neutron beam analysis reveals a faint but consistent periodic feature known as the first sharp diffraction peak (FSDP).

Scientists map activation of prostaglandin E₂ receptor EP1 at atomic level

Prostaglandin E2 (PGE2), a bioactive lipid derived from arachidonic acid, mediates a broad range of physiological processes through four G protein-coupled receptor (GPCR) subtypes: EP1–EP4. While the high-resolution structures of EP2, EP3 and EP4 have been resolved, EP1 remained structurally uncharacterized due to its intrinsic instability, hindering detailed understanding of its Gq-mediated signaling.

In a study published in Proceedings of the National Academy of Sciences, a research team led by Eric H. Xu (Xu Huaqiang) and Xu Youwei from the Shanghai Institute of Materia Medica of the Chinese Academy of Sciences reported the cryo– (cryo-EM) structure of the human EP1 receptor in complexes with PGE2 and the heterotrimeric Gq protein, completed structural atlas of EP receptor family, and revealed EP1-specific mechanisms of ligand recognition and signal transduction.

To overcome the instability of EP1, the researchers employed a multi-pronged engineering strategy, including BRIL fusion, truncation of flexible loops, incorporation of a mini-Gq chimera, and NanoBiT-assisted complex stabilization. They resolved the structure of the EP1–PGE2–Gq complex at 2.55 Å resolution using single-particle cryo-EM, enabling detailed analysis of both ligand binding and G protein coupling interfaces.

Scientists observe collective behavior of femtoscopic droplets at CERN

At CERN’s Large Hadron Collider (LHC), lead atom nuclei, accelerated in opposite directions, collide at speeds close to the speed of light. In such scattering processes, the quarks and gluons that make up these nuclei collide, creating other quarks and gluons, produced by the fundamental interaction known as the “strong interaction.” The number of particles created is around one hundred times greater than the initial number.

As the particles created are numerous and interact strongly with one another, emergent phenomena arise: the whole is more than the sum of its parts. More precisely, the 30,000 or so created particles form a fluid (with droplets of femtoscopic size, 10-14 m), where their individuality disappears.

This description has the advantage of simplicity, as the fluid is characterized by a handful of parameters: (about 2,500 billion degrees) and velocity.

Nuclear Glow Illuminates Dark Matter

High-energy particles or gamma rays are usually needed to kick an atomic nucleus up to a higher-energy state. But last year, scientists excited thorium-229 nuclei with just laser light (see Viewpoint: Shedding Light on the Thorium-229 Nuclear Clock Isomer). Laser-excited nuclei could be useful for making precise timekeepers and sensitive quantum sensors. And now, Wolfram Ratzinger at the Weizmann Institute of Science in Israel and his colleagues have shown how these nuclei also provide a way to detect certain speculative particles that may constitute dark matter [1].

Several models of dark matter involve axions or other extremely light bosons. Thanks to their lightness, these particles would have to be abundant—so much so that they would collectively behave like a classical field, oscillating at a frequency proportional to their mass. The particles’ interactions with the building blocks of nuclei—quarks and gluons—would cause various nuclear properties to oscillate at that same frequency. Among those properties is the energy of the photon emitted by an excited thorium-229 nucleus. Crucially, the oscillations in that energy are predicted to be much more pronounced, and therefore easier to detect, than those in other properties.

Ratzinger and his colleagues conducted the first-ever search for these oscillations in a previously reported spectrum of light emitted by excited thorium-229 nuclei. Finding no oscillations, the researchers set upper limits on the coupling strength of ultralight dark matter particles to quarks and gluons for particles ranging in mass from 10–20 to 10–13 eV. These limits are less stringent than those obtained through other means, but the team anticipates that ongoing and future experiments could set much stronger and possibly decisive constraints.