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Superconductor Theory Under Cold-Atom Scrutiny
Snapshot measurements of cold-atom gases reveal hidden spin correlations that could force an update of some superconductivity theories.
Our understanding of nature is inherently bound to the experimental tools we build to observe the world. Superconductivity, for example, has been traditionally studied using current and voltage meters under a variety of temperatures and other environmental conditions. From these observations, theorists have developed models—notably the Bardeen-Cooper-Schrieffer (BCS) theory, which assumes that the zero-resistance flow in a superconductor arises from electrons forming so-called Cooper pairs. This theory has been successful in explaining a large class of superconductors, but Tarik Yefsah from the Ecole Normale Supérieure in Paris and colleagues have now observed behavior that contradicts BCS predictions [1]. Using a recently developed technique called atom-resolved continuum quantum gas microscopy, the researchers directly observed spatial correlations in cold atoms that mimic superconducting electrons.
Machine learning accelerates analysis of fusion materials
Tungsten’s superior performance in extreme environments makes it a leading candidate for plasma-facing components (PFCs) in fusion reactors, but the ultra-high heat can damage its microscopic structure and lead to component failure. Scanning electron microscopy (SEM) can capture and quantify these microstructure changes, but assembling a sufficiently large dataset of SEM imagery is expensive and logistically challenging.
To augment this dataset, researchers at Oak Ridge National Laboratory trained a generative machine learning model using 3,200 SEM images of tungsten samples exposed to fusion-relevant conditions. The model can generate novel SEM images with realistic microstructures and surface features, such as cracks and pores, without replicating the original images.
“This work is not about making pretty pictures, it’s about capturing the statistics of real damage on these materials,” said ORNL’s Rinkle Juneja, the project’s principal investigator. “We train our generative workflow to learn tungsten’s microstructure signatures, like crack patterns, so it can generate new, statistically consistent microstructures, laying the groundwork for robust, data-driven assessment of PFC fusion materials.”
Gravity follows Newton and Einstein’s rules, even at cosmic scales
Gravity, as most people understand it, is the familiar force that pulls a falling apple toward Earth. But for astronomers and theoretical physicists, it is also a vexing invisible architect that guides the shape and evolution of the largest cosmic structures across the universe.
For decades, puzzling observations of unusually fast-moving galaxies have forced cosmologists like the University of Pennsylvania’s Patricio A. Gallardo to revisit the fundamentals of physics, exploring, for example, whether the laws of gravity as described by Isaac Newton and Albert Einstein truly apply everywhere.
“Astrophysics has been plagued by a massive discrepancy in the cosmic ledger,” says Gallardo. “When we look at how stars orbit within galaxies or how galaxies move within galaxy clusters, some appear to be traveling way too fast for the amount of visible matter they contain.”
Quantum-inspired algorithm solves 268 million-site quasicrystal simulation in a heartbeat
Quantum technologies like quantum computers are built from quantum materials. These types of materials exhibit quantum properties when exposed to the right conditions. Curiously, engineers can also trigger quantum behavior by manipulating a material’s structure; for example, by stacking layers of graphene on top of each other and twisting them to create a moiré pattern, which suddenly turns them into a superconductor.
The layers can be arranged in increasingly complex ways all the way to quasicrystals and super-moiré materials. The fundamental problem is that scientists must first calculate the properties of potential new materials to predict if they could be useful. Quasicrystals, for example, are so complex they can require processing more than a quadrillion numbers—far beyond the capacity of the world’s most powerful supercomputers.
Now researchers at Aalto University’s Department of Applied Physics have shown how a quantum-inspired algorithm makes solving these colossal, non-periodic quantum materials possible in a heartbeat. The research is published in the journal Physical Review Letters as an Editor’s suggestion.
‘Interstellar glaciers’: NASA’s SPHEREx maps vast galactic ice regions
NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) mission has mapped interstellar ice at an unprecedented scale. Covering regions in our Milky Way galaxy more than 600 light-years across, the ice was found inside giant molecular clouds—vast regions of gas and dust where dense clumps of matter collapse under gravity, giving birth to stars. A study describing these findings was published Wednesday in The Astrophysical Journal.
One of SPHEREx’s main goals is to map the chemical signatures of various types of interstellar ice. This ice includes molecules like water, carbon dioxide, and carbon monoxide, which are vital to the chemistry that allows life to develop. Researchers believe these ice reservoirs, attached to the surfaces of tiny dust grains, are where most of the universe’s water is formed and stored. The water in Earth’s oceans —and the ices in comets and on other planets and moons in our galaxy—originates from these regions.
“These vast frozen complexes are like ‘interstellar glaciers’ that could deliver a massive water supply to new solar systems that will be born in the region,” said study co-author Phil Korngut, the instrument scientist for SPHEREx at Caltech in Pasadena, California. “It’s a profound idea that we are looking at a map of material that could rain on nascent planets and potentially support future life.”
A monster black hole appeared first, then its galaxy began to grow around it
Using observations gathered by the James Webb Space Telescope (JWST), an international team of astronomers have revealed that one supermassive black hole in the early universe must have formed before a galaxy developed around it. Publishing their results in Monthly Notices of the Royal Astronomical Society, a team led by Roberto Maiolino at the University of Cambridge hope their results could lead to a better understanding of the origins of these immense objects.
Supermassive black holes (SMBH) are known to lurk at the centers of most galaxies, including our own Milky Way. Carrying up to billions of times the mass of the sun, they have presented a long-standing conundrum to astronomers.
According to our latest models, black holes form from the remnants of supernova explosions, which most often occur when massive stars reach the ends of their lives. Afterwards, they can grow by consuming gas from surrounding accretion disks—but their growth rate is restricted by a brightness threshold called the “Eddington limit.” Beyond this point, the outward pressure from radiation exceeds the gravitational pull, and material is ejected into space.
Astronomers crack a decades-old mystery, catching gas morphing into planet-building disks around newborn stars
An international team led by Dr. Indrani Das of Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) has shown, for the first time, how infalling gas from star-forming cores gradually transitions into planet-forming disks. Their findings, combining numerical simulations with Atacama Large Millimeter/submillimeter Array (ALMA) observations, are published today in The Astrophysical Journal.
Protoplanetary disks form around young stars when dense molecular cloud cores collapse under their own gravity. An outer shroud of gas and dust, known as the envelope, surrounds and feeds both the young star and the forming disk. While it is well understood that planets eventually form within these disks and follow Keplerian orbits, the mechanism that transforms rapid infalling gas motion from the envelope into ordered Keplerian motion within the disk has remained a mystery for decades.
Based on both theoretical and observational evidence, the recent study discovered that there exists a distinct transition zone at the envelope-disk interface of a young star-disk system, which Das named ENDTRANZ (Envelope Disk Transition Zone). The findings have established that infalling gas motions gradually transition into Keplerian motions across this transition zone. Crucially, this transition is far from abrupt and contradicts earlier infall models that are based on classical test-particle dynamics.
Planets need more water to support life than scientists previously thought
Unfortunately for science fiction fans, desert worlds outside our solar system are unlikely to host life, according to new research from the University of Washington. Scientists show that an Earth-sized planet needs at least 20 to 50% of the water in Earth’s oceans to maintain a critical natural cycle that keeps water on the surface.
Scientists believe that there are billions of planets outside our solar system. More than 6,000 of these exoplanets are confirmed, but only some of them are candidates for life. The search for life has focused on planets in the “habitable zone,” a sweet spot that is neither too close nor too far from a central star. Planets in this zone are considered viable because they can maintain liquid surface water.
“When you are searching for life in the broad landscape of the universe with limited resources, you have to filter out some planets,” said lead author Haskelle White-Gianella, a UW doctoral student of Earth and space sciences.