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Laser-assisted electron scattering seen with circularly polarized light for the first time

Researchers from Tokyo Metropolitan University have succeeded in detecting laser-assisted electron scattering (LAES) using circularly polarized light for the first time. The use of circularly polarized light promises valuable insights into how atomic scale “helicity” impacts how electrons interact with matter and light.

Using synchronized femtosecond laser pulses and electron pulses directed at argon atoms, they succeeded in detecting a LAES signal showing excellent agreement with theory. The findings are published in The Journal of Chemical Physics.

LAES is a cutting-edge tool for understanding how electrons interact with matter under the influence of strong fields. When electrons are fired at atoms or molecules, they are scattered in all directions; the presence of strong light can change the way in which the scattering takes place due to an exchange of energy with the surrounding light field.

Not just spin—electron orbitals can provide new method for controlling magnetism

Research is actively underway to develop a “dream memory” that can reduce heat generation in smartphones and laptops while delivering faster performance and lower power consumption. Korean researchers propose a new possibility for controlling magnetism using the exchange interaction of electron orbitals—the motion of electrons orbiting around an atomic nucleus—rather than relying on the conventional exchange interaction of electron spin, the rotational property of electrons inside semiconductors.

A joint research team led by Professor Kyung-Jin Lee of the Department of Physics at KAIST and Professor Kyoung-Whan Kim of the Department of Physics at Yonsei University has established, for the first time in the world, a new theoretical framework enabling magnetism to be freely controlled through orbital exchange interaction, surpassing the limitations of conventional technologies that control magnetism using electric currents. The study is published in the journal Nature Communications.

Until now, next-generation memory research has mainly focused on the spin of electrons. Spin refers to the property of electrons that rotate on their own axis like tiny spinning tops, and information can be stored by using the direction of this rotation. However, electrons simultaneously move around the atomic nucleus along paths known as orbitals.

Could a recently detected ultra-high-energy neutrino be linked to new physics?

Neutrinos are extremely lightweight and electrically neutral particles that rarely interact with ordinary matter. Due to these rare interactions, neutrinos can travel across space almost entirely unaffected, carrying information about highly energetic cosmological events, such as exploding stars or supermassive black holes.

The KM3NeT neutrino telescope, an observatory located at the bottom of the Mediterranean Sea, recently detected the presence of a neutrino carrying extremely high energy, above 100 PeV (peta-electronvolts). This is one of the most energetic neutrinos observed to date.

Theoretical predictions suggested that another large-scale neutrino detector, namely the IceCube detector, would also observe similar high-energy neutrino events. However, this did not happen, which might potentially hint at some new physics, such as a new type of neutrinos or non-standard interactions, that are not included in the standard model of physics.

Physicists break longstanding high-temperature superconductivity record at ambient pressure

Researchers from the Texas Center for Superconductivity (TcSUH) and the department of physics at the University of Houston have broken the temperature record for superconductivity at ambient pressure—a breakthrough that could eventually lead to more efficient ways to generate, transmit, and store energy.

The UH team achieved a transition temperature (Tc) of 151 Kelvin (about minus 122 degrees Celsius) under ambient pressure—the highest ever recorded for all the reported superconductors at ambient pressure since the discovery of superconductivity in 1911. The transition temperature is the point below which a material becomes superconducting, meaning electricity can flow through it without resistance.

Raising this temperature has been a major goal in superconductivity research for decades. The closer scientists can push the Tc toward room temperature, the more practical and affordable superconducting technologies could become.

New microscope offers sharper view into momentum space

Electrons are tiny and constantly in motion. How they behave in a crystal lattice determines key material properties: electrical conductivity, magnetism, or novel quantum effects. Anyone aiming to develop the information technologies of tomorrow must understand what electrons do. At Forschungszentrum Jülich, a new tool is now available for this purpose: a momentum microscope that was fully developed and built on site. “Internationally, we are currently seeing rapidly growing interest in this method,” explains Dr. Christian Tusche from Forschungszentrum Jülich.

Dr. Christian Tusche already played a key role in advancing momentum microscopy during his time at the Max Planck Institute of Microstructure Physics in Halle. Since moving to Jülich in 2015, he has continued to drive its development forward. His work has been recognized with several awards, including the Kai Siegbahn Prize in 2018 and the Innovation Award on Synchrotron Radiation in 2016. Most recently, he published a review article on the method in the journal Applied Physics Letters.

In recent years, numerous instruments have been commissioned at synchrotron facilities and X-ray lasers around the world. “The new device we built together with the Mechanical Workshop is a real innovation. There is currently nothing like it available from any specialist company,” says Dr. Tusche.

Globular cluster NGC 5824 is embedded in a dark matter halo, study suggests

Using data from the Magellan Clay telescope and the Canada-France-Hawaii Telescope (CFHT), astronomers have investigated a galactic globular cluster known as NGC 5824. Results of the new study, available in a paper published March 5 on the arXiv pre-print server, suggest that the cluster is embedded in a dark matter halo.

NGC 5,824 is an old globular cluster (GC) located some 104,000 light years away in the Milky Way’s outer halo. It has a mass of about 1 million solar masses, an age of 12.8 billion years and is the second brightest globular cluster of the outer halo clusters. NGC 5,824 is known to have a diffuse stellar envelope that extends beyond its tidal radius and symmetrically surrounds the cluster.

Given that the origin of the stars in this envelope and whether they remain gravitationally bound to the cluster center is still unclear, a team of astronomers led by Paula B. Díaz of the University of Chile decided to investigate NGC 5,824 by analyzing the data from the survey of the Milky Way outer halo satellites, based on the images acquired by CFHT and the Magellan Clay telescope. The study was complemented by data from ESA’s Gaia satellite.

Communication-aware neural networks could advance edge computing

Edge computing is an emerging IT architecture that enables the processing of data locally by smartphones, autonomous vehicles, local servers, and other IoT devices instead of sending it to be processed at a centralized large data center. This approach could allow artificial intelligence (AI) models and other computational systems to perform tasks rapidly, while consuming less power.

Despite the potential of this approach, typically local devices have a limited battery capacity and restricted computing capabilities. This means they often need to send data to remote cloud servers via the internet to complete complex calculations. This transmission of information via wireless communication can consume significant amounts of energy, while also slowing down the rates of transmission.

Researchers at Nanjing University recently introduced a new approach that could potentially boost the speed of communication between edge devices and cloud servers, while also reducing energy consumption. Their proposed strategy, introduced in a paper published in Nature Electronics, relies on newly developed communication-aware in-memory wireless neural networks, new computational tools that combine computing, memory, and wireless communication into a single AI-powered system.

Novel AI semiconductor uses hydrogen ions for learning and memory

A research team led by Lee Hyun Jun and Noh Hee Yeon from the Division of Nanotechnology at DGIST has succeeded in implementing the world’s first two-terminal-based artificial intelligence (AI) semiconductor that precisely controls hydrogen with electrical signals to enable self-learning and memory. The team’s work appears in Advanced Science.

Whereas modern AI requires the rapid processing of vast amounts of data, the separation of computation and memory in conventional computers results in speed degradation and high power consumption. “Neuromorphic semiconductors,” which perform computation and storage simultaneously by mimicking the human brain, are gaining attention as a next-generation technology that can resolve this problem. At the heart of this semiconductor is an artificial synapse device that changes its conductivity based on electrical signals and maintains that state, and the research team focused on hydrogen as the solution.

Conventional oxide-based memory devices have primarily utilized the migration of oxygen vacancies (defects) as memory. However, this has made it difficult to ensure long-term stability and uniformity between devices. In contrast, the research team solved this problem by developing its own method to precisely control the injection and discharge of hydrogen ions (H+) using an electric field.

First-of-its-kind ion pump developed for seawater desalination, energy and biomedical applications

Researchers at the University of California, Irvine, Israel’s Tel Aviv University and other institutions have developed a first-of-its-kind membrane through which charged molecules pass using nothing more than a rapidly switching low-voltage signal. This “ratchet-based ion pump” has no moving parts and requires no chemical reactions.

The device opens the door to advances in water desalination, lithium ion harvesting from seawater, heavy-metal removal from drinking water, battery recycling and various biomedical applications. The team’s findings are outlined in a paper published recently in Nature Materials.

Mechanically activated liquid metal powder lets users draw circuits on paper

What if electronic circuits could be created simply by drawing lines with a pencil on paper or leaves—and then immediately applied to soft robots or skin-attached health monitoring devices? Korean researchers have developed an electronic materials technology that forms electrically conductive liquid metal in a fine powder form, allowing circuits to be drawn directly on a wide variety of surfaces.

This technology presents new possibilities for next-generation flexible electronics, including applications on paper and plastic as well as in soft robotic systems and wearable devices. The research was published in Advanced Functional Materials.

A research team led by Distinguished Professor Inkyu Park from the Department of Mechanical Engineering, in collaboration with Dr. Hye Jin Kim’s team at the Electronics and Telecommunications Research Institute (ETRI), has developed a liquid metal powder-based electronic material technology that allows electronic circuits to be directly drawn on desired surfaces.

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