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Combinatorial optimization problems (COPs) arise in various fields such as shift scheduling, traffic routing, and drug development. However, they are challenging to solve using traditional computers in a practical timeframe.

Alternatively, annealing processors (APs), which are specialized hardware for solving COPs, have gained significant attention. They are based on the Ising model, in which COP variables are presented as magnetic spins and constraints as interactions between spins. Solutions are obtained by finding the spin state that minimizes the energy of the system.

There are two types of Ising models, the sparsely-coupled model and the fully-coupled model. Sparsely-coupled models offer high scalability by allowing more spins, but require COPs to be transformed to fit the model. Fully-coupled models, on the other hand, allow any COP to be mapped directly without transformation, making them highly desirable.

Using the Five-hundred-meter Aperture Spherical Radio Telescope (FAST), Chinese astronomers have discovered a new millisecond pulsar. The newfound pulsar, designated PSR J2129-1210O, was missed by previous searches as its spin period is close to the harmonics of the known pulsar PSR J2129+1210A.

The finding was reported in a paper published April 23 on the arXiv pre-print server.

Pulsars are highly magnetized, rotating emitting a beam of electromagnetic radiation. The most rapidly rotating pulsars, with rotation periods below 30 milliseconds, are known as (MSPs).

Humans are known to make mental associations between various real-world stimuli and concepts, including colors. For example, red and orange are typically associated with words such as “hot” or “warm,” blue with “cool” or “cold,” and white with “clean.”

Interestingly, some past psychology studies have shown that even if some of these associations arise from people’s direct experience of seeing colors in the world around them, many people who were born blind still make similar color-adjective associations. The processes underpinning the formation of associations between colors and specific adjectives have not yet been fully elucidated.

Researchers at the University of Wisconsin-Madison recently carried out a study to further investigate how language contributes to how we learn about color, using mathematical and computational tools, including Open AI’s GPT-4 (LLM). Their findings, published in Communications Psychology, suggest that color-adjective associations are rooted in the structure of language itself and are thus not only learned through experience.

Scientists at the University of California, Berkeley, and Boise State University have found evidence suggesting that the Marinoan glaciation began approximately 639 million years ago and lasted for approximately 4 million years. In their study published in the Proceedings of the National Academy of Sciences, the group used drone and field imagery along with isotopic dating of glacial deposits to learn more about global glaciation events during the Neoproterozoic Era.

Prior research has shown that during the early days of the planet, during the Neoproterozoic Era, Earth underwent two ice ages. The first, known as the Sturtian glaciation, lasted approximately 56 million years and covered the entire planet with ice. Less is known about the second event, called the Marinoan glaciation. In this new effort, the research team set themselves the task of figuring out when it began and how long it lasted.

The work involved sending drones over a part of Namibia, where prior research has uncovered evidence of glacial activity during the Marinoan. This allowed the team to map that were stacked up in a way that showed little vertical shift had occurred, which meant the glaciers did not move much during the time they were there. Additional field imagery helped confirm what the team found in the images.

University of Oregon researchers have uncovered a molecule produced by yeast living on human skin that showed potent antimicrobial properties against a pathogen responsible for a half-million hospitalizations annually in the United States.

It’s a unique approach to tackling the growing problem of antibiotic-resistant bacteria. With the global threat of drug-resistant infections, fungi inhabiting human skin are an untapped resource for identifying , said Caitlin Kowalski, a postdoctoral researcher at the UO who led the study.

Described in a paper published in Current Biology, the common skin fungus Malassezia gobbles up oil and fats on human skin to produce fatty acids that selectively eliminate Staphylococcus aureus. One out of every three people has Staphylococcus aureus harmlessly dwelling in their nose, but the bacteria are a risk factor for serious infections when given the opportunity: open wounds, abrasions and cuts. They’re the primary cause of skin and soft tissue infections known as staph infections.

Plants are susceptible to a wide range of pathogens. For the common potato plant, one such threat is Pectobacterium atrosepticum, a bacterium that causes stems to blacken, tissues to decay, and often leads to plant death, resulting in significant agricultural losses each year.

In 2012, researchers isolated a new virus that infects and kills this bacterium—a bacteriophage named φTE (phiTE). Now, for the first time, scientists have uncovered the atomic structure of φTE, revealing a possible mechanism of infection that may be more complex than previously thought.

The study, published earlier this month in Nature Communications, is the result of a multidisciplinary collaboration between researchers from the Okinawa Institute of Science and Technology (OIST) and the University of Otago. It brings together expertise across several fields, including virology, , , protein engineering, biochemistry, and biophysics.

Criegee intermediates (CIs)—highly reactive species formed when ozone reacts with alkenes in the atmosphere—play a crucial role in generating hydroxyl radicals (the atmosphere’s “cleansing agents”) and aerosols that impact climate and air quality. The syn-CH3CHOO is particularly important among these intermediates, accounting for 25%–79% of all CIs depending on the season.

Until now, scientists have believed that syn-CH3CHOO primarily disappeared through self-decomposition. However, in a study published in Nature Chemistry, a team led by Profs. Yang Xueming, Zhang Donghui, Dong Wenrui and Fu Bina from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences has uncovered a surprising new pathway: syn-CH3CHOO’s reaction with is approximately 100 times faster than previously predicted by theoretical models.

Using advanced laser techniques, the researchers experimentally measured the reaction rate between syn-CH3CHOO and water vapor, and discovered the faster reaction time. To uncover the reason behind this acceleration, they constructed a high-accuracy full-dimensional (27D) potential energy surface using the fundamental invariant-neural network approach and performed full-dimensional dynamical calculations.

An atomic clock research team from the National Time Service Center of the Chinese Academy of Sciences has proposed and implemented a compact optical clock based on quantum interference enhanced absorption spectroscopy, which is expected to play an important role in micro-positioning, navigation, timing (μPNT) and other systems.

Inspired by the successful history of the coherent population trapping (CPT)-based chip-scale microwave atomic clock and the booming of optical microcombs, a chip-scale optical clock was also proposed and demonstrated with better frequency stability and accuracy, which is mainly based on two-photon transition of Rubidium atom ensemble.

However, the typically required high cell temperatures (~100 ℃) and laser powers (~10 mW) in such a configuration are not compliant with the advent of a fully miniaturized and optical clock.

He Qinglin’s group at the Center for Quantum Materials Science, School of Physics, has reported the first observation of non-reciprocal Coulomb drag in Chern insulators. This breakthrough opens new pathways for exploring Coulomb interactions in magnetic topological systems and enhances our understanding of quantum states in such materials. The work was published in Nature Communications.

Coulomb arises when a current in one conductor induces a measurable voltage in a nearby, electrically insulated conductor via long-range Coulomb interactions.

Chern insulators are magnetic topological materials that show a quantized Hall effect without , due to intrinsic magnetization and chiral edge states.

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.