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New atomic fountain clock joins elite group that keeps the world on time

Clocks on Earth are ticking a bit more regularly thanks to NIST-F4, a new atomic clock at the National Institute of Standards and Technology (NIST) campus in Boulder, Colorado.

This month, NIST researchers published an article in Metrologia establishing NIST-F4 as one of the world’s most accurate timekeepers. NIST has also submitted the clock for acceptance as a primary standard by the International Bureau of Weights and Measures (BIPM), the body that oversees the world’s time.

NIST-F4 measures an unchanging frequency in the heart of cesium atoms, the internationally agreed-upon basis for defining the second since 1967. The clock is based on a “fountain” design that represents the gold standard of accuracy in timekeeping. NIST-F4 ticks at such a steady rate that if it had started running 100 million years ago, when dinosaurs roamed, it would be off by less than a second today.

Combing Through the Sun’s Corona for Dark Matter

Researchers have turned NASA’s Parker Solar Probe into a dark-matter detector, taking advantage of its close encounters with the Sun to search for dark-photon signals.

Dark matter is an elusive but consequential substance. It accounts for 27% of the total energy content of the Universe and plays a crucial role in the formation of cosmic structures, acting as the skeleton for the “cosmic web” of galaxies [1]. However, its nongravitational interactions with known particles remain a mystery. Among the many types of dark-matter particles that have been proposed, a compelling candidate is the ultralight dark photon [2]. Just as the photon mediates the electromagnetic force between electrically charged particles, the dark photon would mediate interactions between a hypothetical set of dark particles. Researchers have previously looked for dark photons using lab-based particle detectors and Earth-bound telescopes. But now Haipeng An from Tsinghua University in China and his colleagues have utilized a unique vantage point next to the Sun to search for a dark-photon signal [3].

Can We Program Life? Rewriting the Rulebook on How Cells Self-Organize

Non-reciprocal interactions between particles enable the regulation of dynamic states. Most systems, whether companies, societies, or entire nations, tend to function most effectively when each member performs their designated role. This efficiency is often supported by spatial organization, whic

Particle Physics Breakthroughs: The Outstanding Contributions of US Universities to Large Hadron Collider Research and Talent Development

Particle Physics Breakthroughs: The Outstanding Contributions of US Universities to Large Hadron Collider Research and Talent Development — fully visualized data of colleges rankings, basic information, admission, graduation, tuition, majors, students, campus safety and more information.

New review urges rigorous testing for single-atom catalysts in industry

Many modern industrial processes depend on complex chemistry. Take fertilizer production, for example: to make it, companies must first produce ammonia, a key ingredient.

These need ingredients of their own—catalysts, which speed up reactions without being consumed or creating unwanted byproducts.

One emerging type of catalyst—known as a “single-atom” or “atomically dispersed” catalyst—is getting a lot of attention for its potential to make industrial processes cleaner and more efficient. Academic journals are overflowing with studies on them.

What is dark energy? One of science’s great mysteries, explained

Dark energy makes up roughly 70% of the universe, yet we know nothing about it.

Around 25% of the universe is the equally mysterious dark matter, leaving just 5% for everything that we can see and touch—matter made up of atoms.

Dark energy is the placeholder name scientists have given to the unknown force causing the universe to expand faster and faster over time.

Scientists discover elusive third type of quantum particle

But now, a bold new idea is challenging this tidy system. Scientists at Rice University in Texas believe there may be a third kind of particle—one that doesn’t follow the rules of fermions or bosons. They’ve developed a mathematical model showing how these unusual entities, called paraparticles, could exist in real materials without breaking the laws of physics.

“We determined that new types of particles we never knew of before are possible,” says Kaden Hazzard, one of the researchers behind the study. Along with co-author Zhiyuan Wang, Hazzard used advanced math to explore this idea.

Their work, published in Nature, suggests that paraparticles might arise in special systems and act differently than anything scientists have seen before.

New physics theory to study low-energy excitations in quantum quasicrystals

Quasicrystals, exotic states of matter characterized by an ordered structure with non-repeating spatial patterns, have been the focus of numerous recent physics studies due to their unique organization and resulting symmetries. Among the quasicrystals that have sparked significant interest among the physics community are so-called quantum quasicrystals, which are comprised of bosons (i.e., subatomic particles that have spin in integer values, such as 0, 1, 2, and so on, and can occupy the same quantum state simultaneously).

Researchers at the Max Planck Institute for the Physics of Complex Systems (MPIPKS) recently introduced a new theoretical framework that describes low-energy excitations in bosonic quantum quasicrystals. Their newly devised theory, outlined in a paper published in Physical Review Letters, is an extension of conventional theories of elasticity, which also accounts for the unique symmetries of quantum quasicrystals.

“This paper is part of an ongoing collaboration with two colleagues, Prof. Francesco Piazza and Dr. Mariano Bonifacio, which began in 2022 when I was a guest scientist at MPIPKS in Dresden, Germany,” Alejandro Mendoza-Coto, first author of the paper, told Phys.org.

Observatory develops high-efficiency muon detection system with novel plastic scintillator design

Researchers from Sun Yat-sen University (SYSU) and the Institute of High Energy Physics (IHEP) have developed a novel top veto tracker system for the Taishan Antineutrino Observatory (TAO) experiment.

This system features a top veto tracker system with remarkable characteristics such as high light yield, distinct signal-background differentiation and high detection efficiency even at high thresholds, and provides the TAO experiment with a robust capability to suppress cosmic muon induced fast neutron and radioisotope events, which are significant correlated backgrounds for the neutrino signal. This scalable solution establishes a transferable technique for next-generation neutrino detectors requiring muon identification efficiency 99.5% across multi-ton volumes.

The findings are published in the journal Nuclear Science and Techniques.