Lifeboat Foundation

The James Webb Space Telescope continues to provide answers about the earliest days of the universe, but it’s also discovering more questions.

Question marks, to be precise. The James Webb Space Telescope (JWST) team at the European Space Agency (ESA) released an image on Wednesday (June 26) offering the most detailed look yet at two actively forming young stars located 1,470 light-years from Earth in the Vela Constellation. In the image, the stars, named Herbig-Haro 46/47, are surrounded by a disk of material that “feeds” the stars as they grow for millions of years.

While the superconducting properties and strong electron correlations observed in two-dimensional moiré superlattices do not persist in the three-dimensional bulk material, the teams’ observed Brown-Zak oscillations suggest that the bizarre characteristics of the 2D systems can be adopted even within thick graphite stacks. There may be a path toward reintroducing these more fascinating properties into bulk materials, Yankowitz says.

Moreover, the persistence of certain 2D behaviors in such thicker structures may explain some odd behaviors of graphite that have been observed as far back as the 1970s. “The behavior of graphite in a very strong magnetic field has been a bit of a mystery for a long time,” says Allan MacDonald, a physicist at the University of Texas at Austin, who did not participate in the work. “And these new papers may give a new handle on trying to understand what’s going on.”

This, Yankowitz says, opens up a new avenue of research in studying hybrid-dimensional materials. “Where this will lead right now is unclear, but it’s the foundation of understanding these new types of hybrid 2D-3D systems,” he says.

Every so often, along comes a story which, like [Fox Mulder] with his unexplained phenomena, we want to believe. EM drives and cold fusion for example would be the coolest of the cool if they worked, but sadly they crumbled when subjected to scientific inquiry outside the labs of their originators. The jury’s still out on the latest example, a claimed room-temperature superconductor, but it’s starting to seem that it might instead be a diamagnetic semiconductor.

We covered some of the story surrounding the announcement of LK-99 and subsequent reports of it levitating under magnetic fields, but today’s installment comes courtesy of a team from Beihang University in Beijing. They’ve published a paper in which they characterize their sample of LK-99, and sadly according to them it’s no superconductor.

Instead it’s a diamagnetic semiconductor, something that in itself probably bears some explanation. We’re guessing most readers will be familiar with semiconductors, but diamagnetic substances possess the property of having an external magnetic field induce an internal magnetic field in the opposite direction. This means that they will levitate in a magnetic field, but not due to the Meissner effect, the property of superconductors which causes magnetic field to flow round their outside. The Beijing team have shown by measuring the resistance of the sample that it’s not a superconductor.

Electronic devices typically use the charge of electrons, but spin — their other degree of freedom — is starting to be exploited. Spin defects make crystalline materials highly useful for quantum-based devices such as ultrasensitive quantum sensors, quantum memory devices, or systems for simulating the physics of quantum effects. Varying the spin density in semiconductors can lead to new properties in a material — something researchers have long wanted to explore — but this density is usually fleeting and elusive, thus hard to measure and control locally.

Now, a team of researchers at MIT and elsewhere has found a way to tune the spin density in diamond, changing it by a factor of two, by… More.

MIT researchers found a way to tune the spin density in diamond by applying an external laser or microwave beam. The finding could open new possibilities for advanced quantum devices.

In a breakthrough for optical computing, researchers developed a nanosecond-scale volatile modulation scheme integrating a phase-change material.

Technological advancements such as autonomous driving and computer vision have spurred a significant increase in demand for computational power. Optical computing, characterized by its high throughput, energy efficiency, and low latency, has attracted significant interest from both academia and industry. However, current optical computing chips are hampered by their power consumption and size, which limit the scalability of optical computing networks.

Nonvolatile integrated photonics has emerged to address these issues, offering optical computing devices the ability to perform in-memory computing while operating with zero static power consumption. Phase-change materials (PCMs), with their high refractive index contrast between different states and reversible transitions, have become promising candidates for enabling photonic memory and nonvolatile neuromorphic photonic chips. This makes PCMs ideally suited for large-scale nonvolatile optical computing chips.

Scientists with the Huazhong University of Science and Technology have replicated LK-99’s levitation abilities at room temperature, which they showcased in a video uploaded to Billibilli.

Topology has become a critical factor in the field of modern condensed matter physics and beyond. It explains the way solid materials may possess two distinct and seemingly conflicting characteristics. An example of this is topological insulators, materials whose bulk acts as an insulator, and can still conduct electricity at their surfaces and edges.

Over the past several decades, the idea of topology has revolutionized the understanding of electronic structure and the overall properties of materials. Additionally, it has opened doors to technological advancements by facilitating the integration of topological materials into electronic applications.

At the same time, topology is quite tricky to measure, often requiring combinations of multiple experimental techniques such as photoemission and transport measurements. A method known as high harmonic spectroscopy has recently emerged as a key technique to observe the topology of a material. In this approach a material is irradiated by intense laser light.

“A place for everything and everything in its place”—making sense of order, or disorder, helps us understand nature. Animals tend to fit nicely into categories: Mammals, birds, reptiles, whatever an axolotl is, and more. Sorting also applies to materials: Insulator, semiconductor, conductor, and even superconductor. Where exactly a material lands in the hierarchy depends on a seemingly invisible interplay of electrons, atoms, and their surroundings.

Unlike animals, the boundaries are less sharp, and tweaking a material’s environment can force it to bounce between categories. For example, dialing down the temperature will turn some materials into superconductors. Snapping on a magnetic field might reverse this effect. Within a single category, different types of order, or phases, can emerge from the sea of particles.

Unfortunately, we can’t see this nanoscopic universe with our eyes, but scientists can use advanced imaging tools to visualize what’s going on. Every once in a while, they uncover unexpected and surprising behaviors.

The main ring is surrounded by a faint halo and with many delicate structures. The interior of the ring is filled with hot gas. The star which ejected all this material is visible at the very center. It is extremely hot, with a temperature in excess (NASA, ESA, CSA, JWST Ring Nebula Team photo; image processing by Roger Wesson)

The images were released Thursday by an international team of astronomers, including three from the Canadian Western University’s Institute for Earth and Space Exploration.