US-UK company Quantinuum has produced a fault-tolerant quantum computer with high performance.
Get the latest international news and world events from around the world.
Vulnerable ALS neurons reveal molecular warning signs before cell death begins
A new study from the Knight Initiative for Brain Resilience researchers may help explain an enduring mystery about amyotrophic lateral sclerosis (ALS): why the disease kills off some of the brain and spinal cord’s movement-controlling neurons while others show greater resilience.
As ALS progresses, more and more of those motor neurons degenerate and die. As a result, patients lose control of their bodies and become unable to breathe. Many people are diagnosed in middle to late adulthood, and most survive only three to five years after diagnosis.
“It’s a cruelly rapid disease,” said Olivia Gautier, a postdoctoral scholar in the lab of Knight Initiative researcher Aaron Gitler, the Stanford Medicine Basic Science Professor and a professor of genetics at Stanford Medicine.
The Placenta: The Organ That Programs Human Health Before Birth | Dr. Perrie O’Tierney-Ginn
Dr. Perrie O’Tierney-Ginn, Ph.D. — Executive Director of the Woman, Mother & Baby Research Institute — Tufts.
Before your heart, brain, or lungs fully developed, one remarkable temporary organ was making decisions that may influence your health for decades. Dr. Perrie O’Tierney-Ginn (https://www.placentascience.com/) explains why the placenta could be the most important organ you’ve never thought about.
Dr. Perrie O’Tierney-Ginn, Ph.D. is Executive Director of the Woman, Mother & Baby Research Institute at Tufts Medical Center (https://www.tuftsmedicine.org/researc… and a Research Associate Professor in both Obstetrics & Gynecology at Tufts University School of Medicine (https://www.tuftsmedicine.org/researc… and the Friedman School of Nutrition Science and Policy (https://nutrition.tufts.edu/academics…).
A self-described \.
Special Spin State Triggered by Curved Surface
The field of magnonics aims to take advantage of spin waves, which are waves of precessing spins that can propagate in certain magnetic materials. A spin wave containing many equally spaced frequencies—called a magnon frequency comb (MFC)—would be especially useful for information processing and magnetic-field detection. Unfortunately, generating such waves is complicated. Now Peng Yan and his colleagues at the University of Electronic Science and Technology of China have shown theoretically that MFCs could be produced by simply creating a tiny bump in a thin magnetic layer [1].
Creating an MFC in a magnetic material usually entails creating an intricate pattern or “texture” of spin orientations in a small region—such as a spin vortex—and irradiating those spins with monochromatic microwaves. To avoid the complexities of spin textures, Yan and his colleagues propose introducing a bump in a few-nanometer-thick magnetic film. Previous research showed that material curvature can affect spin waves, for example, by modifying the frequency–wavelength relationship.
Exploiting another curvature effect, the theorists showed that a bump between 4 and 64 nm high can spontaneously create a set of spin waves that remain restricted to the bump region. Irradiating the bump with microwaves of a specific frequency then excites these waves and launches an MFC that travels away from the bump. Adjusting the height of the bump changes the spacing of the comb frequencies. Team member Hao Zhao says that in addition to possibly making MFCs more widely available, the work shows the potential for using geometry to manipulate spin waves in new ways.
Trios of quantum particles form checkerboard layouts when particle density hits sweet spot
Trions form when three particles, like quarks or electrons, come together. This formation occurs in quantum particles in nuclear physics, semiconductors and magnets, and understanding its behavior can be challenging. Rice University’s Kaden Hazzard and his team recently developed a theory on how these formations occur and behave, which was published in Physical Review Letters.
“Our theory sheds light on how trions form and interact with each other,” said Hazzard, associate professor of physics and astronomy and corresponding author on the paper. “It predicts the strength of the interactions needed to form the trions, and that, after formation, they arrange themselves in a checkerboard pattern.”
If you imagine a space full of equal amounts of red, blue and yellow balls, a trion would form when a red, blue and yellow ball all stuck to each other, Hazzard explained. Once all the balls, or particles, are bound together, he was curious about how these trions would arrange themselves in space.
A thermodynamic approach to gravity could explain cosmic acceleration without dark energy
Gravity, the force that attracts objects toward each other, is currently framed by Albert Einstein’s theory of general relativity. This framework describes gravity as the curvature of spacetime, the invisible four-dimensional fabric of the universe.
While general relativity is now the central theory of gravity, it fails to explain some cosmological phenomena and mysteries, such as the so-called cosmological constant problem. This is the unexplained mismatch between the observed energy of empty space and the far greater values predicted by quantum theories.
In a recent paper published in Physical Review Letters, researchers at Imperial College London tried to frame gravity using thermodynamics, the framework that describes how energy and heat transform. Their study builds on a seminal paper by theoretical physicist Ted Jacobson, published more than three decades ago.
The universe should look the same in all directions at large scales, but DESI data suggest otherwise
Earlier this year, the Dark Energy Spectroscopic Instrument (DESI) completed observations that mapped 47 million galaxies across 11 billion light-years, allowing astronomers to better evaluate the large-scale structure of the visible universe. After studying these data, astronomers Francesco Sylos Labini and Marco Galoppo say the universe may not look the same in all directions. Their results, published in Nature, contradict a fundamental assumption in modern cosmology.
At the scale of a single galaxy or local groups of galaxies, the universe clearly appears to be anisotropic, meaning the structure is different depending on which direction you look. In one direction, there may be more void space, while another direction may have a cluster of galaxies.
However, the cosmological principle says that at larger scales, the universe consists of matter that is more or less distributed evenly in all directions. This is based on the Copernican principle, which states that there should be no “special observers” in the universe, meaning that at large scales, the universe should look the same from anywhere else in the universe.
Scientists find molecular-level evidence for two structures in liquid water
A study published in Nature Physics provides new molecular-level evidence from simulations that liquid water is not a single uniform substance, but a constantly shifting mixture of two distinct microscopic structures.
The idea that water might exist in two distinct structural states is not new. For decades, scientists have theorized that liquid water is composed of two interconvertible local structures—one denser and more disordered, the other less dense and more ordered.
This “two-state model” has been invoked to explain water’s many anomalous properties, including why it becomes easier to compress as it cools and why it reaches maximum density at 4°C (39°F) rather than at its freezing point. But the model has remained controversial because direct molecular-level evidence for the two structures has been elusive.
Thirsty desert lizards inspire a new water-harvesting system
When the desert horned lizard (Phrynosoma platyrhinos) is thirsty, it cannot just lap up water or scoop it up like a bird because it lives in environments where water is extremely scarce. Typically, it’s found in damp soil or, even more rarely, in drops of rain.
Instead, its skin contains microscopic channels between overlapping scales that pull in moisture by capillary action. But how it gets that water from these channels into its mouth has remained a mystery until now.
Scientists have discovered how that happens, and it inspired them to design a water-harvesting system that borrows from how the reptiles do it.