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A team of researchers affiliated with several institutions in Israel has used a Floquet quantum detector to constrain axion-like dark matter, hoping to reduce its parameter space. In their paper published in the journal Science Advances, the group describes their approach to constraining the theoretical dark matter particle as a means to learning more about its properties.

Despite several years of effort by physicists around the world, dark matter remains a mystery. Most physicists agree that it exists, but thus far, no one has been able to prove it. One promising theory involving the existence of interacting massive particles has begun to lose its luster, and some teams are looking for something else. In this new effort, the researchers seek axions, or axion-like particles. Such dark matter particles have been theorized to be zero-spin and able to possess any number of combinations of mass and interaction strength. The team sought to constrain the features of axion-like particles to reduce the number of possibilities of their existence and thereby increase the chances of proving their existence.

The researchers used a shielded glass cell filled with rubidium-85 and xenon-129 atoms. They fired two lasers at the cell—one to polarize the rubidium atoms’ electronic spin and the xenon’s nuclear spin, and the other to measure spin changes. The experiment was based on the idea that the oscillating field of the axions would impact on the xenon’s spin when they are close in proximity. The researchers then applied a magnetic field to the cell as a means of blocking the spin of the xenon to within a narrow range of frequencies, allowing them to scan the possible oscillation frequencies that correspond to the range of the axion-like particles. Under this scenario, the Floquet field is theorized to have a frequency roughly equal to the difference between the nuclear magnetic resonance (NMR) and the electron paramagnetic resonance, and their experiment closes that gap.

Strongly interacting systems play an important role in quantum physics and quantum chemistry. Stochastic methods such as Monte Carlo simulations are a proven method for investigating such systems. However, these methods reach their limits when so-called sign oscillations occur.

This problem has now been solved by an international team of researchers from Germany, Turkey, the U.S., China, South Korea and France using the new method of wavefunction matching. As an example, the masses and radii of all nuclei up to mass number 50 were calculated using this method. The results agree with the measurements, the researchers now report in the journal Nature.

All matter on Earth consists of tiny particles known as atoms. Each atom contains even smaller particles: protons, neutrons and electrons. Each of these particles follows the rules of quantum mechanics. Quantum mechanics forms the basis of quantum many-body theory, which describes systems with many particles, such as atomic nuclei.

Exploring the complex domain of subatomic particles, researchers at the The Institute of Mathematical Science (IMSc) and the Tata Institute of Fundamental Research (TIFR) have recently published a novel finding in the journal Physical Review Letters. Their study illuminates a new horizon within quantum chromodynamics (QCD), shedding light on exotic subatomic particles and pushing the boundaries of our understanding of the strong force.

Every year, beer breweries generate and discard thousands of tons of surplus yeast. Researchers from MIT and Georgia Tech have now come up with a way to repurpose that yeast to absorb lead from contaminated water.

Through a process called biosorption, yeast can quickly absorb even trace amounts of lead and other heavy metals from water. The researchers showed that they could package the yeast inside hydrogel capsules to create a filter that removes lead from water. Because the yeast cells are encapsulated, they can be easily removed from the water once it’s ready to drink.

“We have the hydrogel surrounding the free yeast that exists in the center, and this is porous enough to let water come in, interact with yeast as if they were freely moving in water, and then come out clean,” says Patricia Stathatou, a former postdoc at the MIT Center for Bits and Atoms, who is now a research scientist at Georgia Tech and an incoming assistant professor at Georgia Tech’s School of Chemical and Biomolecular Engineering.

Antiferromagnetic spintronics offer high speed operations, and reduced issues with stray fields compared to ferromagnetic systems, however, antiferromagnets are typically more challenging to manipulate electrically. Here, Yang, Kim, and coauthors demonstrate electrical control of magnon dispersion and frequency in an α-Fe2O3/Pt heterostructure.

A new nucleosynthesis process denoted as the νr-process has been suggested by scientists from GSI Helmholtzzentrum für Schwerionenforschung, Technische Universität Darmstadt, and the Max Planck Institute for Astrophysics. It operates when neutron-rich material is exposed to a high flux of neutrinos.

The first stars of the universe were monstrous beasts. Comprised only of hydrogen and helium, they could be 300 times more massive than the sun. Within them, the first of the heavier elements were formed, then cast off into the cosmos at the end of their short lives. They were the seeds of all the stars and planets we see today. A new study published in Science suggests these ancient progenitors created more than just the natural elements.

Except for hydrogen, helium, and a few traces of other light elements, all of the atoms we see around us were created through astrophysical processes, such as supernovae, collisions of neutron stars, and high-energy particle collisions. Together they created heavier elements up to Uranium-238, which is the heaviest naturally occurring element. Uranium is formed in supernova and neutron star collisions through what is known as the r-process, where neutrons are rapidly captured by atomic nuclei to become a heavier element. The r-process is complex, and there is still much we don’t understand about just how it occurs, or what its upper mass-limit might be. This new study, however, suggests that the r-process in the very first stars could have produced much heavier elements with atomic masses greater than 260.

The team looked at 42 stars in the Milky Way for which the elemental composition is well understood. Rather than simply looking for the presence of heavier elements, they looked at the relative abundances of elements across all the stars. They found that the abundance of some elements such as silver and rhodium doesn’t agree with the predicted abundance from known r-process nucleosynthesis. The data suggests that these elements are the decay remnants from much heavier nuclei of more than 260 atomic mass units.

The Standard Model of Particle Physics is scientists’ best understanding of the forces that describe how subatomic particles interact. The Standard Model encompasses four forces: the strong nuclear force, the weak nuclear force, the electromagnetic force, and the gravitational force. All four forces govern the way our universe works. However, the weak nuclear force is exceptionally difficult to study as it is overshadowed by the much greater effects of the strong nuclear and electromagnetic forces.

In its superconducting state, an exotic metal harbors charge carriers that appear to have 4 and 6 times the charge of a single electron, suggesting the formation of Cooper-pair “molecules.”

A kagome crystal features two-dimensional atomic layers whose structure resembles a traditional Japanese basket weave called kagome. For several decades, the kagome crystals that attracted the most attention were insulating magnets. The geometric frustration inherent in their kagome structure could, it was hoped, engender a much-sought exotic state known as a quantum spin liquid. By contrast, the metallic side of the kagome family was more of a theoretical curiosity. That status changed in 2019 with the discovery of exotic electronic behavior—Dirac fermions and flat bands—in the kagome metal FeSn [1]. A bigger surprise followed a year later when superconductivity was observed in the kagome metal cesium vanadium antimonide (CsV₃Sb₅, or CVS for short) [2].