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Category: physics

New LVK catalog adds 128 gravitational-wave candidates, more than doubling detections

When the densest objects in the universe collide and merge, the violence sets off ripples, in the form of gravitational waves, that reverberate across space and time, over hundreds of millions and even billions of years. By the time they pass through Earth, such cosmic ripples are barely discernible.

And yet, scientists are able to detect them, thanks to a global network of gravitational-wave observatories: the U.S.-based National Science Foundation Laser Interferometer Gravitational-Wave Observatory (NSF LIGO), the Virgo interferometer in Italy, and the Kamioka Gravitational Wave Detector (KAGRA) in Japan. Together, the observatories “listen” for faint wobbles in the gravitational field that could have come from far-off astrophysical smash-ups.

Now the LIGO-Virgo-KAGRA (LVK) Collaboration is publishing its latest compilation of gravitational-wave detections, presented in a forthcoming special issue of Astrophysical Journal Letters. From the findings, it appears that the universe is echoing all over with a kaleidoscope of cosmic collisions.

Molecular ‘catapult’ fires electrons at the limits of physics

Electrons can be “kicked across” solar materials at almost the fastest speed nature allows, scientists have discovered, challenging long-held theories about how solar energy systems work. The finding could help researchers design more efficient ways of harvesting sunlight and converting it into electricity. The research is published in Nature Communications.

In experiments capturing events lasting just 18 femtoseconds —less than 20 quadrillionths of a second—researchers at the University of Cambridge observed charge separation happening within a single molecular vibration.

“We deliberately designed a system that—according to conventional theory—should not have transferred charge this fast,” said Dr. Pratyush Ghosh, Research Fellow, at St John’s College, Cambridge, and first author of the study. “By conventional design rules, this system should have been slow, and that’s what makes the result so striking.

Chimps’ love for crystals could help us understand our own ancestors’ fascination with these stones

Crystals have repeatedly been found at archaeological sites alongside Homo remains. Evidence shows that hominins have been collecting these stones for as long as 780,000 years. Yet, we know that our ancestors did not use them as weapons, tools, or even jewelry. So why did they collect them at all?

Now, in a new study appearing in Frontiers in Psychology, scientists in Spain have investigated which characteristics of crystals may have made them so fascinating to our ancestors. They designed experiments with chimpanzees—one of the two great ape species most closely related to modern humans—to identify the physical properties of crystals that may have attracted early hominins.

“We show that enculturated chimpanzees can distinguish crystals from other stones,” said lead author Prof. Juan Manuel García-Ruiz, an Ikerbasque Research Professor of crystallography at the Donostia International Physics Center in San Sebastián. “We were pleasantly surprised by how strong and seemingly natural the chimpanzees’ attraction to crystals was. This suggests that sensitivity to such objects may have deep evolutionary roots.”

What Geminga’s 100 TeV cutoff may mean for cosmic-ray acceleration in the Milky Way

For the first time, the Tibet ASγ Experiment has successfully measured magnetohydrodynamic (MHD) turbulence on scales below one parsec (approximately 3.3 light-years) within the gamma-ray halo surrounding the Geminga pulsar wind nebula (PWN). This observation extends to the highest energies, above 100 tera-electron volts (TeV), providing new insights into the behavior of cosmic rays and magnetic fields within the Milky Way.

The findings are published in Science Advances. The study was conducted by the Tibet ASγ Experiment, including the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences (CAS) and the National Astronomical Observatories of CAS.

Reduce rust by dumping your wok twice, and other kitchen tips

When you reach the bottom of a container of milk or honey, you might be tempted to tip the container over to get that last pesky little bit out. After all, you only need another teaspoon for that recipe, and you’re sure it’s in there. From emptying jars to drying dishes, research about thin film flows in the kitchen highlights everyday connections to physics.

In Physics of Fluids, researchers from Brown University present two related studies about thin film fluid flows in the kitchen: one about the relationship between how long it takes to tip the remaining liquid out of a container and its viscosity, and the other about the ideal time to wait before dumping water out of a wok to minimize rusting—it’s more effective to wait a few minutes to let the water accumulate so there’s more to pour out. “The kitchen is sort of the prime laboratory,” said author Jay Tang. “It deals with a lot of chemistry, materials science, and physics.”

Most people have an intuitive sense of what viscosity is, often described as how thick a fluid feels. It is measured scientifically by applying a certain amount of force to a fluid and measuring its flow rate.

Hidden atomic dichotomy drives superconductivity in ultra-thin compound

Physicists in China have unveiled new clues to the origins of high-temperature superconductivity in an iron-based material just a single unit-cell thick. Led by Qi-Kun Xue and Lili Wang at Tsinghua University, the team’s experiments show that the effect emerges through a striking dichotomy between two atomic “sublattices” in the material—offering deeper insight into how superconductivity arises. Their results are published in Physical Review Letters.

When cooled below its critical temperature, a superconductor allows electrical currents to flow with virtually zero resistance. While most superconductors discovered so far have critical temperatures close to absolute zero, recent decades have seen the discovery of increasingly advanced materials that host the effect at ever higher temperatures, making them far easier to implement for practical applications.

In 2012, superconductivity was discovered in a single-unit-cell-thick layer of iron selenide (FeSe), consisting of a Se–Fe–Se trilayer only 0.55 nm thick. However, it remained unclear how such a strong superconducting effect could emerge in such an ultrathin system.

Light-powered soft robot jumps 188 times without electronics

An insect-scale robot that jumps using only light has completed 188 continuous leaps without a single electronic component.

The soft machine bends, snaps and resets itself automatically, powered entirely by material physics instead of chips or wires.

The robot is built mainly from liquid crystal elastomers, a rubber-like material that changes shape when exposed to light. When illuminated, the material bends and stores elastic energy in a curved beam structure.

3D-printed ‘plug’ links fiber optics to photonic chips with low loss

Physicists and chemists at Heidelberg University have realized a photonic microchip that is driven by light just as easily as electronic components via a “plug.” Their development could serve as the basis for fast and cost-effective production of photonic integrated systems that are of great importance for implementing innovative computing and communications systems.

Prof. Dr. Wolfram Pernice of the Kirchhoff Institute for Physics headed up the research on this novel coupling concept for light-controlled chips. The results appear in the journal Science Advances.

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