A startup from former Google X employees is building an AI app that acts as a “second brain.”
A recent study by researchers identifies pterostilbene nanoliposomes (PT-NLPs) which addresses long-standing challenges with pterostilbene.
Evidence suggests Mars could very well have been teeming with life billions of years ago. Now cold, dry, and stripped of what was once a potentially protective magnetic field, the red planet is a kind of forensic scene for scientists investigating whether Mars was indeed once habitable, and if so, when.
The “when” question in particular has driven researchers in Harvard’s Paleomagnetics Lab in the Department of Earth and Planetary Sciences. A new paper in Nature Communications makes their most compelling case to date that Mars’ life-enabling magnetic field could have survived until about 3.9 billion years ago, compared with previous estimates of 4.1 billion years—so hundreds of millions of years more recently.
The study was led by Griffin Graduate School of Arts and Sciences student Sarah Steele, who has used simulation and computer modeling to estimate the age of the Martian “dynamo,” or global magnetic field produced by convection in the planet’s iron core, like on Earth. Together with senior author Roger Fu, the John L. Loeb Associate Professor of the Natural Sciences, the team has doubled down on a theory they first argued last year that the Martian dynamo, capable of deflecting harmful cosmic rays, was around longer than prevailing estimates claim.
The identification of a new type of symmetry in statistical mechanics could help scientists derive and interpret fundamental relationships in this branch of physics.
Symmetry is a foundational concept in physics, describing properties that remain unchanged under transformations such as rotation and translation. Recognizing these invariances, whether intuitively or through complex mathematics, has been pivotal in developing classical mechanics, the theory of relativity, and quantum mechanics. For example, the celebrated standard model of particle physics is built on such symmetry principles. Now Matthias Schmidt and colleagues at the University of Bayreuth, Germany, have identified a new type of invariance in statistical mechanics (the theoretical framework that connects the collective behavior of particles to their microscopic interactions) [1]. With this discovery, the researchers offer a unifying perspective on subtle relationships between observable properties and provide a general approach for deriving new relations.
The concept of conserved, or time-invariant, properties has roots in ancient philosophy and was crucial to the rise of modern science in the 17th century. Energy conservation became a cornerstone of thermodynamics in the 19th century, when engineers uncovered the link between heat and work. Another important type of invariance is Galilean invariance, which states that the laws of physics are identical in all reference frames moving at a constant velocity relative to each other, resulting in specific relations between positions and velocities in different frames. Its extension, Lorentz invariance, posits that the speed of light is independent of the reference frame. Einstein’s special relativity is based on Lorentz invariance, while his general relativity broadens the idea to all coordinate transformations. These final examples illustrate that invariance not only provides relations between physical observables but can shape our understanding of space, time, and other basic concepts.
A new analysis of B-meson decays strongly hints that they harbor physics beyond the standard model.
By manipulating and detecting nuclear spins in a tiny floating diamond, scientists have reported a record-long spin coherence time for a levitated system.
Contrary to conventional wisdom, a lattice of engineered nanoparticles called meta-atoms can have a chiral optical response even when each meta-atom is not chiral.
A new framework that embeds electrons in a surrounding bath captures nonlocal correlation effects that are relevant to metals, semiconductors, and correlated insulators.
Searching for new types of superconductors, magnets, and other useful materials is a bit like weaving a tapestry with threads of many different colors. The weaver selects a short-range (local) pattern for how the individual threads intertwine and at the same time chooses colors that will give an overall (nonlocal) mood. A materials scientist works in a similar way, mixing atoms instead of threads, trying to match the motion of their electrons—their correlations—on both local and nonlocal scales. Doing so by trial-and-error synthesis is time intensive and costly, and therefore numerical simulations can be of huge help. To contribute to bridging computations to material discovery, Jiachen Li and Tianyu Zhu from Yale University have developed a new approach that treats local and nonlocal electronic correlations on an equal footing [1] (Fig. 1). They demonstrated their method by accurately predicting the photoemission spectra of several representative materials.
Low-frequency radio observations could allow researchers to distinguish among several dark matter models, thanks to dark matter’s influence on the early Universe.
The profusion of dark matter candidates reflects how easy it is for any of them to explain the current large-scale structure of the Universe. Decisive clues about dark matter’s true nature are more likely to appear at earlier epochs. Unfortunately, those clues are harder to observe. Now Jo Verwohlt of the University of Copenhagen in Denmark and her collaborators have shown how a deeply redshifted hydrogen line could unmask dark matter [1]. To do so, they also identified confounding signatures from regular, baryonic matter.
Some theories posit that dark matter interacts with so-called dark radiation. In the dense early Universe, the heating effect of that interaction could have been enough for large concentrations of dark matter known as halos to temporarily and repeatedly resist gravitational collapse. Termed dark acoustic oscillations (DAOs), these cycles of expansion and collapse would have quickly died out. But before they did, they could have affected the onset of “cosmic dawn.” That’s when the first galaxies formed from primordial gas drawn into the halos.
The search for the universe’s dark matter could end tomorrow—given a nearby supernova and a little luck. The nature of dark matter has eluded astronomers for 90 years, since the realization that 85% of the matter in the universe is not visible through our telescopes. The most likely dark matter candidate today is the axion, a lightweight particle that researchers around the world are desperately trying to find.
Astrophysicists at the University of California, Berkeley, now argue that the axion could be discovered within seconds of the detection of gamma rays from a nearby supernova explosion. Axions, if they exist, would be produced in copious quantities during the first 10 seconds after the core collapse of a massive star into a neutron star, and those axions would escape and be transformed into high-energy gamma rays in the star’s intense magnetic field.
Such a detection is possible today only if the lone gamma-ray telescope in orbit, the Fermi Gamma-ray Space Telescope, is pointing in the direction of the supernova at the time it explodes. Given the telescope’s field of view, that is about one chance in 10.
