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Dual-cation strategy boosts upconversion efficiency in stable oxide perovskites

Researchers at the Hefei Institutes of Physical Science of the Chinese Academy of Sciences have developed a new way to significantly enhance upconversion luminescence in oxide perovskites, a class of materials known for their thermal and chemical stability but limited optical efficiency.

Led by Professor Jiang Changlong, the team introduced a dual-cation substitution strategy in titanate perovskites by precisely adjusting the sodium-to-lithium ratio at the crystal’s A-site. This controlled substitution triggers a structural transition that improves energy transfer between rare-earth ions, resulting in a marked increase in luminescence intensity and quantum yield.

The findings are published in Journal of Alloys and Compounds.

Researchers discover a new superfluid phase in non-Hermitian quantum systems

A stable “exceptional fermionic superfluid,” a new quantum phase that intrinsically hosts singularities known as exceptional points, has been discovered by researchers at the Institute of Science Tokyo.

Their analysis of a non-Hermitian quantum model with spin depairing shows that dissipation can actively stabilize a superfluid with these singularities embedded within it. The work reveals how lattice geometry dictates the phase’s stability and provides a path to realizing it in experiments with ultracold atoms.

In the quantum world, open quantum systems are those where particle loss and directional asymmetry are fundamental features. These systems can no longer be described by conventional mathematics.

New materials, old physics—the science behind how your winter jacket keeps you warm

As the weather grows cold this winter, you may be one of the many Americans pulling their winter jackets out of the closet. Not only can this extra layer keep you warm on a chilly day, but modern winter jackets are also a testament to centuries-old physics and cutting-edge materials science.

Winter jackets keep you warm by managing heat through the three classical modes of heat transfer —conduction, convection and radiation—all while remaining breathable so sweat can escape.

The physics has been around for centuries, yet modern material innovations represent a leap forward that let those principles shine.

New optical method reveals micellar structure changes under extensional stress

Complex fluids, such as polymer melts and concentrated suspensions, are foundational materials for industrial products, including high-strength plastics and optical components. The final performance of these materials depends on their composition and internal microscopic structure. During manufacturing processes, however, fluids are subjected to mechanical forces that introduce internal stress, leading to microscopic structural damage, which in turn affects the material’s functionality.

Despite the pressing need to observe and control this structure–stress relationship, few measurement techniques are available for fluids subjected to uniaxially extensional flow. Conventional optical techniques, owing to their low resolution and scope, fail to accurately track changes in the region of maximum stress, making it difficult to link mechanical stresses with observable optical changes.

Addressing this challenge, a research team from Nagoya Institute of Technology (NITech) in Japan, led by Assistant Professor Masakazu Muto recently developed a novel rheo-optical technique that can accurately characterize structural deformations in a complex fluid under extensional flow. Collaborators included Mr. Naoki Kako, Mr. Tatsuya Yoshino, and Professor Shinji Tamano.

New model showcases microbubble behavior in viscoelastic fluid under ultrasound forcing

Encapsulated microbubbles (EMBs), tiny gas-filled bubbles coated in lipid or protein shells, play a central role in biomedical ultrasound. When exposed to ultrasound waves, EMBs contract, resulting in oscillations that enhance image contrast or deliver drugs directly by creating pores in cell membranes via sonoporation. However, while promising for biomedical applications, their behavior is far more complex.

Most existing theories on EMBs assume spherically symmetrical oscillations and only study them in simple Newtonian fluids. However, most biological fluids, such as blood, are viscoelastic (non-Newtonian) fluids. When inside the body, these fluid forces, pressure from vessel walls, and changing ultrasound pulses can influence the behavior of EMBs, affecting both imaging accuracy and treatment safety.

To better understand these effects, a multi-institutional research team has developed a comprehensive computational model that simulates the behavior of EMBs under real biological conditions. The team included Assistant Professor Haruki Furukawa and Professor Shuichi Iwata from Nagoya Institute of Technology (NITech), Japan, in collaboration with Emeritus Professor Tim N. Phillips, Dr. Michael J. Walters, and Reader Steven J. Lind from Cardiff University, Wales.

New method uses spin motion to control heat flow in magnetic materials

NIMS, in joint research with the University of Tokyo, AIST, the University of Osaka, and Tohoku University, have proposed a novel method for actively controlling heat flow in solids by utilizing the transport of magnons—quasiparticles corresponding to the collective motion of spins in a magnetic material—and demonstrated that magnons contribute to heat conduction in a ferromagnetic metal and its junction more significantly than previously believed.

The creation of new principles “magnon engineering” for modulating thermal transport using magnetic materials is expected to lead to the development of thermal management technologies. This research result is published in Advanced Functional Materials.

Thermal conductivity is a fundamental parameter characterizing heat conduction in a solid. The primary heat carriers are known to be electrons and phonons, quasiparticles corresponding to lattice vibrations. In current thermal engineering, efforts are underway to modulate thermal conductivity and interfacial thermal resistance by elucidating and controlling the transport properties of heat carriers. In particular, heat conduction modulation focusing on the transport and scattering of phonons has been actively studied over the past decades as “phonon engineering.”

Evidence of a quantum spin liquid ground state in a kagome material

Quantum spin liquids are exotic states of matter in which spins (i.e., the intrinsic angular momentum of electrons) do not settle into an ordered pattern and continue to fluctuate, even at extremely low temperatures. This state is characterized by high entanglement, a quantum effect that causes particles to become linked so that the state of one affects the others’ states, even over long distances.

Researchers at SLAC National Accelerator Laboratory and Stanford University recently gathered evidence of intrinsic quantum spin liquid behavior in a kagome material, a magnetic material in which atoms are arranged in a particular pattern known as a kagome lattice. Their findings, published in Nature Physics, could help to further delineate the fundamental principles underpinning quantum spin liquid states.

“I’ve been interested in understanding quantum spin liquids for the past 20+ years,” Young S. Lee, senior author of the paper, told Phys.org. “These are fascinating new states of quantum matter. In principle, their ground states may possess long-range quantum entanglement, which is extremely rare in real materials.

Your Music Playlist Could Influence Your Driving Ability in Unexpected Ways

For many of us, listening to music is simply part of the driving routine – as ordinary as wearing a seatbelt. We build playlists for road trips, pick songs to stay awake, and even turn the volume up when traffic gets stressful.

More than 80 percent of drivers listen to music on most trips. And many young drivers find it difficult to concentrate without it.

We tend to think music relaxes us, energises us, or helps us focus when we’re behind the wheel.

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