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Category: physics – Page 13

New perspectives on light-matter interaction: How virtual charges influence material responses

Understanding what happens inside a material when it is hit by ultrashort light pulses is one of the great challenges of matter physics and modern photonics. A new study published in Nature Photonics and led by Politecnico di Milano reveals a hitherto neglected but essential aspect, precisely the contribution of virtual charges, charge carriers that exist only during interaction with light, but which profoundly influence the material’s response.

The research, conducted in partnership with the University of Tsukuba, the Max Planck Institute for the Structure and Dynamics of Matter, and the Institute of Photonics and Nanotechnology (CNR-IFN) investigated the behavior of monocrystalline diamonds subjected to lasting a few attoseconds (billionths of a billionth of a second), using an advanced technique called attosecond-scale transient reflection spectroscopy.

By comparing with state-of-the-art , researchers were able to isolate the effect of so-called virtual vertical transitions between the electronic bands of the material. Such an outcome changes the perspective on how light interacts with solids, even in hitherto attributed only to the movement of actual charges.

Key enzyme for high-value natural sweetener production identified and characterized

Steviol glycosides, natural sweeteners extracted from Stevia rebaudiana, are widely used as sucrose substitutes due to their high sweetness and low caloric value. Among them, Rebaudioside M (Reb M) is regarded as a next-generation, high-value steviol glycoside product because of its intense sweetness and superior taste profile. However, the natural abundance of Reb M in Stevia is extremely low.

Efficient biosynthetic methods are needed to meet market demand. Until now, the key enzyme catalyzing the conversion of Rebaudioside D (Reb D) to Reb M in the has not been identified, and it is generally assumed to be UGT76G1. However, UGT76G1 exhibits strict regioselectivity for the C13 position of steviol glycosides, while its at the C19 position is very weak.

In a study published in the Proceedings of the National Academy of Sciences on September 17, a team led by Prof. Yin Heng from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences identified the key glycosyltransferase that catalyzes the conversion of Reb D to Reb M, and revealed the underlying its substrate regioselectivity.

Researchers develop the first room temperature all-solid-state hydride ion battery

Hydride ion (H-), with their low mass and high redox potential, are considered promising charge carriers for next-generation electrochemical devices. However, the lack of an efficient electrolyte with fast hydride ion conductivity, thermal stability, and electrode compatibility has hindered their practical applications.

In a study published in Nature, Prof. Chen Ping’s group from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) developed a novel core–shell ion electrolyte, and constructed the first room temperature all-solid-state rechargeable hydride ion battery.

Using a heterojunction-inspired design, researchers synthesized a novel core–shell composite hydride, 3CeH3@BaH2, where a thin BaH2 shell encapsulates CeH3. This structure leverages the high hydride ion conductivity of CeH3 and the stability of BaH2, enabling fast hydride ion conduction at room temperature along with high thermal and electrochemical stability.

Self-locked microcomb on a chip tames Raman scattering to achieve broad spectrum and stable output

A research team has successfully developed a self-locked Raman-electro-optic (REO) microcomb on a single lithium niobate chip. By synergistically harnessing the electro-optic (EO), Kerr, and Raman effects within one microresonator, the microcomb has a spectral width exceeding 300 nm and a repetition rate of 26.03 GHz, without the need for external electronic feedback.

The research was published in the Nature Communications. The team was led by Prof. Dong Chunhua from the University of Science and Technology of China (USTC), in collaboration with Prof. Bo Fang’s group from Nankai University.

Optical frequency combs, light sources composed of equally spaced frequency lines, are essential tools in modern optical communications, , and fundamental physics research. While traditional are typically based on bulky mode-locked lasers, recent advances in integrated photonics have enabled chip-scale Kerr and EO combs.

Rare-earth tritellurides reveal a hidden ferroaxial order of electronic origin

The discovery of “hidden orders,” organization patterns in materials that cannot be detected using conventional measurement tools, can yield valuable insight, which can in turn support the design of new materials with advantageous properties and characteristics. The hidden orders that condensed matter physicists hope to uncover lie within so-called charge density waves (CDWs).

CDWs are periodic wave-like modulations of the electronic charge inside a crystal. CDWs in rare-earth tellurides, compounds containing tellurium and other rare-earth elements, have been found to sometimes give rise to unusual physical phenomena that are not observed in the absence of these wave-like states of matter.

Researchers at Boston College, Cornell University and other institutes recently observed a ferroaxial order in rare-earth tellurides that appears to originate from a combination of coupled orbital and charge patterns.

TRAPPIST-1e observations narrow down possibilities for atmosphere and surface water on elusive exoplanet

University of Bristol astrophysicists are helping shed new light on an Earth-sized exoplanet 40 light years away where liquid water in the form of a global ocean or icy expanse might exist on its surface. That would only be possible if an atmosphere is present—a big mystery that the scientists are attempting to unravel and now even closer to solving using the largest telescope in space.

Deploying NASA’s JWST, the researchers have reached these discoveries as part of a major international project which is probing the atmosphere and surface of TRAPPIST-1e, also more simply known as planet e in the system, orbiting within the habitable zone of red dwarf star TRAPPIST-1.

Exoplanets are highly varied planets which orbit stars outside the solar system. Planet e is of particular interest because the presence of liquid water—not too hot or cold—is theoretically viable, but only if the planet has an atmosphere.

Google DeepMind discovers new solutions to century-old problems in fluid dynamics

For centuries, mathematicians have developed complex equations to describe the fundamental physics involved in fluid dynamics. These laws govern everything from the swirling vortex of a hurricane to airflow lifting an airplane’s wing.

Experts can carefully craft scenarios that make theory go against practice, leading to situations which could never physically happen. These situations, such as when quantities like velocity or pressure become infinite, are called ‘singularities’ or ‘blow ups’. They help mathematicians identify fundamental limitations in the equations of fluid dynamics, and help improve our understanding of how the physical world functions.

In a new paper, we introduce an entirely new family of mathematical blow ups to some of the most complex equations that describe fluid motion. We’re publishing this work in collaboration with mathematicians and geophysicists from institutions including Brown University, New York University and Stanford University.

Solar breakthrough — hotter panels mean better storage

Scientists have uncovered a surprising advantage in next-generation solar technology—the hotter it gets, the better it can store energy. Traditionally, heat has been seen as the enemy of solar power. Standard solar panels lose efficiency as temperatures rise.

But a new study, published in The Journal of Chemical Physics, shows that in special “solar-plus-storage” devices, heat can actually boost performance by speeding up the internal chemical reactions that store energy.

The team studied photoelectrochemical (PEC) flow cells—an emerging technology that combines the sunlight-harvesting ability of a solar panel with the storage power of a battery.

Neuromorphic Intelligence Leverages Dynamical Systems Theory To Model Inference And Learning In Sustainable, Adaptable Systems

The pursuit of artificial intelligence increasingly focuses on replicating the efficiency and adaptability of the human brain, and a new approach, termed neuromorphic intelligence, offers a promising path forward. Marcel van Gerven from Radboud University and colleagues demonstrate how brain-inspired systems can achieve significantly greater energy efficiency than conventional digital computers. This research establishes a unifying theoretical framework, rooted in dynamical systems theory, to integrate insights from diverse fields including neuroscience, physics, and artificial intelligence. By harnessing noise as a learning resource and employing differential genetic programming, the team advances the development of truly adaptive and sustainable artificial intelligence, paving the way for emergent intelligence arising directly from physical substrates.

Researchers demonstrate that applying dynamical systems theory, a mathematical framework describing change over time, to artificial intelligence enables the creation of more sustainable and adaptable systems by harnessing noise as a learning tool and allowing intelligence to emerge from the physical properties of the system itself.

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