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Apr 17, 2023

The comprehensive characterization of hydrogen at ultra-high pressures

Posted by in categories: materials, physics

Physicists and material scientists have been trying to metallize hydrogen for many decades, but they have not yet succeeded. In 1968, British physicist Neil Ashcroft predicted that atomic metallic hydrogen would be a high-temperature semiconductor.

Most recent studies also suggested that this elusive and hypothetical form of hydrogen would also conduct electricity with no resistance when its temperature exceeds that of boiling water. This prediction ultimately paved the way for the discovery of high-temperature superconductivity in hydrides (i.e., compounds containing hydrogen and a metal).

Researchers at Sapienza University of Rome, Sorbonne University, CNRS, and the International School for Advanced Studies (SISSA) have recently carried out a study aimed at thoroughly characterizing the behavior and properties of hydrogen at high pressures. Their paper, published in Nature Physics, outlines a highly accurate phase diagram of high-pressure hydrogen, which could inform ongoing efforts aimed at creating atomic metallic hydrogen.

Apr 17, 2023

Study demonstrates the non-volatile electrical control of a 2D magnetic insulator using a thin ferroelectric polymer

Posted by in categories: computing, materials

Two-dimensional (2D) magnetic insulators, which are electrically insulating materials with long-range magnetic order, could be used to fabricate compact magneto-electric or magneto-optical devices. Efficiently and reliably controlling the properties of these atomically thin magnets through electrical means, however, has so far proved to be highly challenging, as the materials’ charge levels often cannot be largely adjusted and their crystal fields cannot be considerably altered using external electric fields.

Researchers at University of Maryland and their collaborators recently devised a new strategy that could be used to efficiently control 2D magnetic insulators. This strategy, outlined in a paper in Nature Electronics, relies on the use of a thin ferroelectric polymer that can modulate the 2D materials’ magnetic responses.

“When it comes to , people are primarily pursuing a smaller form factor (relating to higher integration density, which means more devices can be integrated on the unit area/volume of a chip), lower energy consumption, and higher performance,” Cheng Gong, the lead principal investigator for the study, told Tech Xplore.

Apr 17, 2023

Solar sails could guide interplanetary travel, says new study

Posted by in category: space

Space travel has brought us to our next-door neighbor, the moon, and to the depths of our larger solar community inhabited by giants such as Saturn and Jupiter.

In 1982, Voyager 2 whisked past Uranus closer than any other spacecraft has since, and now is sailing—46 years after its launch—through the constellation of Pavo, some 179 from Earth.

But there have been few comparable satellite missions in recent years. Cost is the main obstacle, but time frame is also a factor. The design for such long journeys takes years to calculate, and planning and construction of a space vehicle would take about a decade. Factoring in the time a satellite would require to reach distant targets means our next peek into the stars will likely not come any time soon.

Apr 17, 2023

Quantum light source goes fully on-chip, bringing scalability to the quantum cloud

Posted by in categories: computing, internet, quantum physics

An international team of researchers from Leibniz University Hannover (Germany), the University of Twente (Netherlands), and the start-up company QuiX Quantum has presented an entangled quantum light source fully integrated for the first time on a chip. The results of the study were published in the journal Nature Photonics.

“Our breakthrough allowed us to shrink the source size by a factor of more than 1,000, allowing reproducibility, stability over a longer time, scaling, and potentially mass-production. All these characteristics are required for real-world applications such as ,” says Prof. Dr. Michael Kues, head of the Institute of Photonics, and board member of the Cluster of Excellence PhoenixD at Leibniz University Hannover.

Quantum bits () are the basic building blocks of quantum computers and the quantum internet. Quantum light sources generate light quanta (photons) that can be used as . On-chip photonics has become a leading platform for processing optical quantum states as it is compact, robust, and allows to accommodate and arrange many elements on a . Here, light is directed on the chip through extremely compact structures, which are used to build photonic quantum computing systems. These are already accessible today through the cloud. Scalably implemented, they could solve tasks that are inaccessible to conventional computers due to their limited computing capacities. This superiority is referred to as quantum advantage.

Apr 17, 2023

Physicists discover first transformable nanoscale electronic devices

Posted by in categories: mobile phones, nanotechnology, quantum physics

The nanoscale electronic parts in devices like smartphones are solid, static objects that once designed and built cannot transform into anything else. But University of California, Irvine physicists have reported the discovery of nanoscale devices that can transform into many different shapes and sizes even though they exist in solid states.

It’s a finding that could fundamentally change the nature of , as well as the way scientists research atomic-scale quantum materials. The study is published in Science Advances.

“What we discovered is that for a particular set of materials, you can make nanoscale electronic devices that aren’t stuck together,” said Javier Sanchez-Yamagishi, an assistant professor of physics & astronomy whose lab performed the new research. “The parts can move, and so that allows us to modify the size and shape of a device after it’s been made.”

Apr 17, 2023

Physicists find unusual waves in nickel-based magnet

Posted by in category: particle physics

Perturbing electron spins in a magnet usually results in excitations called “spin waves” that ripple through the magnet like waves on a pond that’s been struck by a pebble. In a new study, Rice University physicists and their collaborators have discovered dramatically different excitations called “spin excitons” that can also “ripple” through a nickel-based magnet as a coherent wave.

In a study published in Nature Communications, the researchers reported finding unusual properties in nickel molybdate, a layered magnetic crystal. Subatomic particles called electrons resemble miniscule magnets, and they typically orient themselves like compass needles in relation to magnetic fields. In experiments where neutrons were scattered from magnetic nickel ions inside the crystals, the researchers found that two outermost electrons from each nickel ion behaved differently. Rather than aligning their spins like compass needles, the two canceled one another in a phenomenon physicists call a spin singlet.

“Such a substance should not be a magnet at all,” said Rice’s Pengcheng Dai, corresponding author of the study. “And if a neutron scatters off a given nickel ion, the excitations should remain local and not propagate through the sample.”

Apr 17, 2023

Computer scientists create ‘believable’ human interactions in AI world of Smallville

Posted by in categories: robotics/AI, virtual reality

Make a template based on a 1980s virtual reality game, create 25 AI characters, give them personalities and histories, equip them with memory, and throw in some ChatGPT—and what do you get?

A pretty impressive representation of a functioning society with compelling, believable human interactions.

That’s the conclusion of six from Stanford University and Google Research who designed a Sims-like environment to observe the daily routines of inhabitants of an AI-generated virtual town.

Apr 17, 2023

Humans Are Erasing Billions of Years of Data From Ancient Meteorites

Posted by in categories: evolution, space

A popular and easy method for validating whether or not a chunk of rock is a meteorite, and what kind of meteorite it is, has been inadvertently erasing invaluable information locked inside.

The use of rare-earth magnets such as neodymium erases and overwrites the magnetic record locked inside ferromagnetic minerals in meteorites, scientists from MIT in the US and Paris Cité University in France found. Since many meteorites that fall to Earth have a significant iron content, this means we’re losing important data on the way magnetic fields in space have altered these meteorites over billions of years.

Meteorites provide invaluable records of planetary formation and evolution. Studies of their paleomagnetism have constrained accretion in the protoplanetary disk, the thermal evolution and differentiation of planetesimals, and the history of planetary dynamos.

Apr 17, 2023

Researchers discover how some brain cells transfer material to neurons in mice

Posted by in categories: biotech/medical, life extension, neuroscience

Researchers at UC Davis are the first to report how a specific type of brain cells, known as oligodendrocyte-lineage cells, transfer cell material to neurons in the mouse brain. Their work provides evidence of a coordinated nuclear interaction between these cells and neurons. The study was published today in the Journal of Experimental Medicine.

“This novel concept of material transfer to neurons opens new possibilities for understanding brain maturation and finding treatments for neurological conditions, such as Alzheimer’s disease, cerebral palsy, Parkinson’s and Huntington’s disease,” said corresponding author Olga Chechneva is an assistant project scientist at UC Davis Department of Biochemistry and Molecular Medicine and independent principal investigator in the Institute for Pediatric Regenerative Medicine at Shriners Children’s Northern California.

Oligodendrocyte-lineage , also called oligodendroglia, are a type of glial cells found in the central nervous system. From birth onward, these glial cells arise to support neural circuit maturation. They are mostly known for their role in myelination—the formation of the insulating myelin sheath around nerve axons.

Apr 17, 2023

What it will look like if China launches cyberattacks in the U.S.

Posted by in categories: cybercrime/malcode, government, internet, military

Chinese hackers could also attack the networks of companies that provide services to the military or to critical infrastructure operators, holding their systems hostage for ransom payments.

“If you get the right supply chain, it can have a lot of effects against a lot of targets,” said John Hultquist, head of Mandiant Intelligence Analysis at Google Cloud.

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