Psychology.
Experiments identify temperature ranges where exotic materials known as spin ices are in equilibrium or out of equilibrium.
Periodic structures known as metamaterials can interact with electromagnetic waves in unusual ways. In one counterintuitive example, standing waves remain trapped in a volume even though they’re surrounded by radiating waves that should carry their energy away. These standing waves, called bound states in the continuum (BICs), can provide a boost to resonant systems—such as lasers, filters, or sensors—by mitigating radiative losses. Researchers have recently demonstrated a promising design that produces high-quality BICs; however, it works only at microwave frequencies. Simulations by Pietro Brugnolo and his colleagues at the Technical University of Denmark now suggest that a straightforward change could allow the design to be adapted to optical wavelengths [1].
The previous design involves thin metamaterials, or metasurfaces, made of metallic bars arranged around cylindrical cavities. In such a configuration, BICs emerge when characteristic metasurface resonances match the cavity resonance. The metallic elements, however, result in resistive losses when used at wavelengths shorter than those of microwaves. Brugnolo’s team thus set out to investigate an all-dielectric version of the scheme.
The researchers simulated devices in which the metallic elements were replaced with silicon particles distributed on a cylindric surface. Their results showed that the structure displayed both an electrical and an effective magnetic response, which could be tailored to create the standing-wave patterns characteristic of BICs. For a wave at telecommunication wavelengths (1550 nm), their simulations predicted a cavity quality factor of 1.7 × 104, on par with the microwave version of the same scheme.
Temporal measurements in conditions similar to those in the Sun rebut a leading hypothesis for why models and experiments disagree on how much light iron absorbs.
Understanding how light interacts with matter inside stars is crucial for predicting stars’ evolution, structure, and energy output. A key factor in this process is opacity—the degree to which a material absorbs radiation. Recent experimental findings have challenged long-standing models, showing that iron, a major contributor to stellar opacity, absorbs more light than expected. This discrepancy has profound implications for our understanding of the Sun and of other stars. Over the past two decades, three groundbreaking studies [1–3] have taken major steps toward resolving this mystery, using advanced laboratory experiments to measure iron’s opacity under extreme conditions similar to those of the Sun’s interior. However, the discrepancy remained, with researchers hypothesizing that it came from systematic errors from temporal gradients in plasma properties.
In a new Physical Review Letters study, researchers propose an experimental approach that could finally determine whether gravity is fundamentally classical or quantum in nature.
The nature of gravity has puzzled physicists for decades. Gravity is one of the four fundamental forces, but it has resisted integration into the quantum framework, unlike the electromagnetic, strong, and weak nuclear forces.
Rather than directly tackling the challenging problem of constructing a complete quantum theory of gravity or trying to detect individual gravitons—the hypothetical mediator of gravity—the researchers take a different approach.
Iron oxide minerals are found in rocks around the globe. Some are magnetic, and some of them rust—especially when exposed to water and oxygen. These characteristics provide clues about the history of these minerals.
Utah State University geoscientists describe a new forensic tool for determining the timing of geochemical oxidation reactions in iron-oxide minerals occurring in the Earth’s crust, which could shed light on how and when large, unexplained gaps in the rock record—known as “unconformities”—developed.
“A challenge for geoscientists is accurately constraining when rocks resided in the near-surface environment,” says Alexis Ault, associate professor in USU’s Department of Geosciences. “It’s tricky to pinpoint the timing of such processes, because the geologic evidence has often been erased.”
The Electronic Frontier Foundation (EFF) has released a free, open-source tool named Rayhunter that is designed to detect cell-site simulators (CSS), also known as IMSI catchers or Stingrays.
Stingray devices mimic legitimate cell towers to trick phones into connecting, allowing them to capture sensitive data, accurately geolocate users, and potentially intercept communications.
With the release of the Rayhunter, EFF seeks to give users the power to detect these instances, allowing them to protect themselves and also help draw a clearer picture of the exact deployment scale of Stingrays.
YouTube warns that scammers are using an AI-generated video featuring the company’s CEO in phishing attacks to steal creators’ credentials.
The attackers are sharing it as a private video with targeted users via emails claiming YouTube is changing its monetization policy.
“We’re aware that phishers have been sharing private videos to send false videos, including an AI generated video of YouTube’s CEO Neal Mohan announcing changes in monetization,” the online video sharing platform warned in a pinned post on its official community website.
In a new development that could help redefine the future of technology, a team of physicists has uncovered a fundamental insight into the upper limit of superconducting temperature.
This research, accepted for publication in the Journal of Physics: Condensed Matter, suggests that room-temperature superconductivity —long considered the “holy grail” of condensed matter physics—may indeed be possible within the laws of our universe.
Superconductors, materials that can conduct electricity without resistance, have the potential to revolutionize energy transmission, medical imaging, and quantum computing. However, until now, they have only functioned at extremely low temperatures, making them impractical for widespread use. The race to find a superconductor that works at ambient conditions has been one of the most intense and elusive pursuits in modern science.