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Quantum-dot device can generate multiple frequency-entangled photons

Researchers have designed a new device that can efficiently create multiple frequency-entangled photons, a feat that cannot be achieved with today’s optical devices. The new approach could open a path to more powerful quantum communication and computing technologies.

“Entangling particles efficiently is a critical capability for unlocking the full power of quantum technologies—whether to accelerate computations, surpass fundamental limits in precision measurement, or guarantee unbreakable security using the laws of quantum physics,” said Nicolas Fabre from Telecom Paris at the Institut Polytechnique de Paris.

“Photons are ideal because they can travel long distances through optical fibers or free space; however, there hasn’t been a way to efficiently generate frequency entanglement between more than two photons.”

Massive impact could be the cause of our lopsided moon

Our nearest neighbor, the moon, is still something of a mystery to us. For decades, scientists have wondered why it appears so lopsided, with dark volcanic plains on the near side (the side we see) and rugged, cratered mountains and a thicker crust on the far side. Now we might be closer to knowing why.

Analysis of lunar soil and rock brought back from the far side by China’s Chang’e-6 mission suggests that a massive impact long ago changed the moon’s interior.

The samples were collected from the South Pole-Aitken basin, a massive impact crater covering nearly one-quarter of the moon’s surface. Because it is so deep, researchers from the Chinese Academy of Sciences wanted to see whether the impact had reached the moon’s mantle and changed its chemistry.

Fluid gears rotate without teeth, offering new mechanical flexibility

A team of New York University scientists has created a gear mechanism that relies on fluids to generate rotation. The invention holds potential for a new generation of mechanical devices that offer greater flexibility and durability than do existing gears—whose origins date back to ancient China.

The breakthrough is reported in the journal Physical Review Letters.

“We invented new types of gears that engage by spinning up fluid rather than interlocking teeth—and we discovered new capabilities for controlling the rotation speed and even direction,” says Jun Zhang, a professor of mathematics and physics at NYU and NYU Shanghai and the senior author of the paper.

Cyanobacteria can utilize toxic guanidine as a nitrogen source

Guanidine is an organic compound primarily used as a denaturing reagent to disrupt the structures of proteins and nucleic acids. Together with partner institutions, scientists at the Helmholtz Centre for Environmental Research (UFZ) have demonstrated that cyanobacteria, which play a central role in global biogeochemical cycles, use guanidine as a nitrogen source.

The results were recently published in the Proceedings of the National Academy of Sciences. The researchers shed light on the underlying mechanisms and the potential for a new tool for sustainable biotechnological applications.

Deformable lens enables real-time correction of image aberrations in single-pixel microscopy

Researchers from the Optics Group at the Universitat Jaume I in Castellón have managed to correct in real time problems related to image aberrations in single-pixel microscopy using a recent technology: programmable deformable lenses. The new method was described by the research team in an open-access article recently published in Nature Communications and is part of the development of the European CONcISE project.

The solution proposed by this team combines an adaptive lens (which “shapes” the light wavefront in real time) with a sensorless method that evaluates image sharpness directly from the data, without complex algorithms. This approach corrects distortions caused both by the system and by the sample itself, producing sharper images, close to the physical resolution limit, without adding complexity to the microscope.

This adaptive lens is known as a “multi-actuator adaptive lens” (M-AL), which can be easily integrated into the system without significantly modifying the traditional configuration of a single-pixel microscope based on structured illumination. These types of lenses consist of an optically transparent and deformable membrane (similar to a thin sheet of glass or polymer) that can change shape via actuators distributed around or behind it.

New tool lets anyone audit a country’s methane claims

For years, countries have told the United Nations how much methane they emit using a kind of bottom-up bookkeeping: Count the cows and oil barrels, estimate the volume of trash, and multiply by standard emission factors.

Those ledgers can miss the mark, suggest measurements from aircraft and satellites. But the tools to translate that data into national emissions estimates have largely remained the domain of specialists.

A team at Harvard is changing that. In a recent Nature Communications paper, the researchers describe Integrated Methane Inversion (IMI), an open-access system designed to let governments, researchers and civil society independently evaluate national methane claims against what satellites detect in the atmosphere, year after year.

Enthusiasts used their home computers to search for ET—scientists are homing in on 100 signals they found

For 21 years, between 1999 and 2020, millions of people worldwide loaned UC Berkeley scientists their computers to search for signs of advanced civilizations in our galaxy.

The project—called SETI@home, after the Search for Extraterrestrial Intelligence (SETI)—generated a loyal following eager to participate in one of the most popular crowd-sourced projects in the early days of the internet. They downloaded the SETI@home software to their home computers and allowed it to analyze data recorded at the now-defunct Arecibo Observatory in Puerto Rico to find unusual radio signals from space.

All told, these computations produced 12 billion detections— momentary blips of energy at a particular frequency coming from a particular point in the sky, according to computer scientist and project co-founder David Anderson.

New global standard set for testing graphene’s single-atom thickness

Graphene could transform everything from electric cars to smartphones, but only if we can guarantee its quality. The University of Manchester has led the world’s largest study to set a new global benchmark for testing graphene’s single-atom thickness. Working with the UK’s National Physical Laboratory (NPL) and 15 leading research institutes worldwide, the team has developed a reliable method using transmission electron microscopy (TEM) that will underpin future industrial standards.

Researchers at the University of Manchester, working with the UK’s National Physical Laboratory and 15 international partners, have developed a robust protocol using transmission electron microscopy (TEM). The results, published in 2D Materials, will underpin a new ISO technical specification for graphene.

“To incorporate graphene and other 2D materials into industrial applications, from light-weight vehicles to sports equipment, touch screens, sensors and electronics, you need to know you’re working with the right material. This study sets a global benchmark that industry can trust,” said Dr. William Thornley, who worked on the research during his Ph.D.

A dry surface thanks to fluid physics: Contact-free method gently remove liquids from delicate microstructures

Researchers at the University of Konstanz have developed a gentle, contact-free method to collect liquids and remove them from microscopic surface structures. The method uses vapor condensation to generate surface currents that transport droplets off surfaces.

Many modern technologies rely on microscopic elements, such as microchips in smartphones. The manufacturing process for these elements requires their surfaces to be exposed to different types of liquids that must be completely removed afterward.

A research team led by Stefan Karpitschka from the University of Konstanz has now developed a new method that uses surface tension to efficiently transport these liquids off the finished product. The work is published in the journal Proceedings of the National Academy of Sciences.

Taming heat: Novel solution enables unprecedented control of heat conduction

Prof. Gal Shmuel of the Faculty of Mechanical Engineering at the Technion—Israel Institute of Technology has developed an innovative approach that enables precise control of heat conduction in ways that do not occur naturally.

The breakthrough could lead to new applications in energy harvesting and in protecting heat-sensitive devices. The research, conducted in collaboration with Prof. John R. Willis of the University of Cambridge, was published in Physical Review Letters.

The researchers’ approach is based on designing materials with asymmetric and nonuniform microstructures, inspired by similar methods previously developed for controlling light and sound—but never applied before to heat conduction. The challenge in adapting these ideas stems from the fact that light and sound propagate as waves, while heat spreads through a spontaneous process known as diffusion.

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