An anonymous reader quotes a report from Phys.Org: A team of scientists at Freie Universitat Berlin has developed an artificial intelligence (AI) method for calculating the ground state of the Schrodinger equation in quantum chemistry. The goal of quantum chemistry is to predict chemical and physical properties of molecules based solely on the arrangement of their atoms in space, avoiding the need for resource-intensive and time-consuming laboratory experiments. In principle, this can be achieved by solving the Schrodinger equation, but in practice this is extremely difficult. Up to now, it has been impossible to find an exact solution for arbitrary molecules that can be efficiently computed. But the team at Freie Universitat has developed a deep learning method that can achieve an unprecedented combination of accuracy and computational efficiency.

The deep neural network designed by [the] team is a new way of representing the wave functions of electrons. "Instead of the standard approach of composing the wave function from relatively simple mathematical components, we designed an artificial neural network capable of learning the complex patterns of how electrons are located around the nuclei," [Professor Frank Noe, who led the team effort] explains. "One peculiar feature of electronic wave functions is their antisymmetry. When two electrons are exchanged, the wave function must change its sign. We had to build this property into the neural network architecture for the approach to work," adds [Dr. Jan Hermann of Freie Universitat Berlin, who designed the key features of the method in the study]. This feature, known as 'Pauli's exclusion principle,' is why the authors called their method 'PauliNet.' Besides the Pauli exclusion principle, electronic wave functions also have other fundamental physical properties, and much of the innovative success of PauliNet is that it integrates these properties into the deep neural network, rather than letting deep learning figure them out by just observing the data. "Building the fundamental physics into the AI is essential for its ability to make meaningful predictions in the field," says Noe. "This is really where scientists can make a substantial contribution to AI, and exactly what my group is focused on." The results were published in the journal Nature Chemistry.

An anonymous reader shares a report: Some diamonds were formed billions of years ago in space as the carbon-rich atmospheres of dying stars expanded and cooled. In our own planet's lifetime, high-temperatures and pressures in the mantle produced the diamonds that are familiar to us as gems. 5,000 years ago, a large meteorite that struck a carbon-rich sediment on Earth produced an impact diamond. Each of these diamonds differs from the others in both composition and genesis, but all are categorized as "diamond" by the authoritative guide to minerals -- the International Mineralogical Association's Commission on New Minerals, Nomenclature and Classification. For many physical scientists, this inconsistency poses no problem. But the IMA system leaves unanswered questions for planetary scientists, geobiologists, paleontologists and others who strive to understand minerals' historical context.

So, Carnegie's Robert Hazen and Shaunna Morrison teamed up with CU Boulder philosophy of science professor Carol Cleland to propose that scientists address this shortcoming with a new "evolutionary system" of mineral classification -- one that includes historical data and reflects changes in the diversity and distribution of minerals through more than 4 billion years of Earth's history. Their work is published by the Proceedings of the National Academy of Sciences. "We came together from the very different fields of philosophy and planetary science to see if there was a rigorous way to bring the dimension of time into discussions about the solid materials that compose Earth," Hazen said.

An anonymous reader quotes a report from NBC News: Several European countries have banned flights from the U.K. over fears about a new coronavirus variant that has forced millions of people in Britain to cancel their Christmas plans. Germany, the Netherlands, Belgium, Austria and Italy all announced restrictions on U.K. travel. Others will likely follow suit as scientists warned that the new strain spreads more quickly than its predecessor. [...] U.K. health officials first identified the new variant, which British scientists have called "VUI -- 202012/01," in mid-September, Maria Van Kerkhove, the Covid-19 technical lead for the World Health Organization, told the BBC on Sunday.

Chris Whitty, the chief medical officer for England, warned in a statement Saturday that it the virus considered to be spreading more quickly. But he said there was no evidence so far to suggest that the new strain is more potent in terms of severe illness or death. "Our working assumption from all the scientists is that the vaccine response should be adequate for this virus," Patrick Vallance, the U.K. government's chief scientific adviser, said at a news briefing Saturday. But Ravindra Gupta, a professor of clinical microbiology at the University of Cambridge, said he was concerned that the virus is on a pathway to become resistant to vaccines. "Whilst it may not be actually resistant, it may not take so many changes after this for it to get there," he said. However, Clarke said that different versions of flu vaccines are required every year and that he did not see why it could not be the same for the coronavirus. The report notes that the new variant "has so far been identified in Denmark, the Netherlands and Australia," adding that more sequencing that can be done will be helpful to determine if this variant is circulating elsewhere.

Gupta said the new strain should be cause for concern in the U.S. and other countries. Warning that the virus could mutate again, he said, "people need to step up their surveillance."

A team of astronomers has discovered evidence in over 150 galaxies for a long-standing alternative model of "modified gravity." New Atlas reports: [R]esearchers on the new study say they've observed the [external field effect] (EFE) in action in 153 different galaxies. The team was studying the rotation curve of the galaxies, which plots the orbital speed of stars and gas against their distance from the center of the galaxy. The researchers discovered that galaxies in strong external fields slowed down much more frequently than galaxies in weaker external fields did. That's a prediction made only by [Modified Newtonian dynamics] MOND, and the discovery surprised even the astronomers themselves.

"The external field effect on rotation curves is expected to be very tiny," says Federico Lelli, co-author of the study. "We spent months checking various systematics. In the end, it became clear we had a real, solid detection." It's an intriguing result, and it may lend some weight to the MOND hypothesis for further study. But it's important to keep in mind that so far the bulk of the evidence still points towards dark matter, and it'll take much more work to topple that hypothesis entirely. The research was published in the Astrophysical Journal.

Jupiter and Saturn will appear as a double planet in the night sky Monday evening thanks to a rare planetary alignment known as a "great conjunction." Axios explains how to see it: In order to see the two planets, step outside under clear skies not long after sundown and look to the southwest. Jupiter will look brighter than Saturn and will appear just above the ringed planet. If you hold out your hand to the sky, the tip of your pinky will be able to cover both planets at once, according to NASA. The two planets will be bright enough to see from most cities. For those interested, NASA has a dedicated article on how to photograph the conjunction.