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Temporal anti-parity–time symmetry offers new way to steer energy through systems

The movement of waves, patterns that carry sound, light or heat, through materials has been widely studied by physicists, as it has implications for the development of numerous modern technologies. In several materials, the movement of waves depends on a physical property known as parity-time (PT) symmetry, which combines mirror-like spatial symmetry with a symmetry in a system’s behavior when time runs forward and backwards.

Systems with PT symmetry can suddenly alter their behavior when they pass specific thresholds known as phase transitions, where they shift from balanced to unbalanced states. So far, systems exhibiting PT symmetry are mostly static, meaning that they exhibit fixed properties over time.

In Nature Physics, researchers at University of Shanghai for Science and Technology, Fudan University and National University of Singapore introduce a new concept called temporal anti-parity–time (APT) symmetry, which delineates more clearly both where and when a phase transition happens in a non-Hermitian system, a system that exchanges energy with its surroundings.

The ocean absorbed a stunning amount of heat in 2025

Earth’s oceans reached their highest heat levels on record in 2025, absorbing vast amounts of excess energy from the atmosphere. This steady buildup has accelerated since the 1990s and is now driving stronger storms, heavier rainfall, and rising sea levels. While surface temperatures fluctuate year to year, the ocean’s long-term warming trend shows no sign of slowing.

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.

Sunlight-driven nanoparticles enable cleaner ammonia synthesis at room temperature

Ammonia (NH3) is a colorless chemical compound comprised of nitrogen and hydrogen that is widely used in agriculture and in industrial settings. Among other things, it is used to produce fertilizers, as well as cleaning products and explosives.

Currently, ammonia is primarily produced via the so-called Haber-Bosch process, an industrial technique that entails prompting a reaction between nitrogen and hydrogen at very high temperatures and pressure. Despite its widespread use, this process is known to be highly energy-intensive and is estimated to be responsible for approximately 3% of global greenhouse gas emissions.

Researchers at Stanford University School of Engineering, Boston College and other institutes have identified new promising catalysts (i.e., materials that speed up chemical reactions) that could enable the sunlight-driven synthesis of ammonia at room temperature and under normal atmospheric pressure.

Acid-treated carbon nanotubes boost efficiency and stability of flexible perovskite solar modules

Flexible perovskite solar modules (f-PSMs) are a key innovation in current renewable energy technology, offering a pathway toward sustainable and efficient energy solutions. However, ensuring long-term operational stability without compromising efficiency or increasing material costs remains a critical challenge.

In a study published in Joule, a joint research team from the Institute of Metal Research (IMR) of the Chinese Academy of Sciences and Zhengzhou University has achieved power conversion efficiency (PCE) surpassing 20% in flexible modules capable of withstanding a range of external stresses. The study highlights the use of single-walled carbon nanotubes (SWCNTs) as window electrodes for scalable f-PSMs.

SWCNT films exhibit excellent hydrophobicity, resisting moisture-induced degradation while enhancing device stability. Their flexibility and affordability further position SWCNT-based electrodes as a practical option for sustainable energy systems, providing an ideal opportunity for buildings and infrastructure to incorporate their own power sources in support of a net-zero carbon emissions future.

Iron-based magnetic material achieves major reduction in core loss

A research team from NIMS, Tohoku University and AIST has developed a new technique for controlling the nanostructures and magnetic domain structures of iron-based soft amorphous ribbons, achieving more than a 50% reduction in core loss compared with the initial amorphous material.

The developed material exhibits particularly high performance in the high-frequency range of several tens of kilohertz—required for next-generation, high-frequency transformers and EV drive power supply circuits. This breakthrough is expected to contribute to the advancement of these technologies, development of more energy-efficient electric machines and progress toward carbon neutrality.

The research is published in Nature Communications.

MIT engineers fly first-ever plane with no moving parts

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Since the first airplane took flight over 100 years ago, virtually every aircraft in the sky has flown with the help of moving parts such as propellers, turbine blades, or fans that produce a persistent, whining buzz.

Now MIT engineers have built and flown the first-ever plane with no moving parts. Instead of propellers or turbines, the light aircraft is powered by an “ionic wind” — a silent but mighty flow of ions that is produced aboard the plane, and that generates enough thrust to propel the plane over a sustained, steady flight.

Unlike turbine-powered planes, the aircraft does not depend on fossil fuels to fly. And unlike propeller-driven drones, the new design is completely silent.

Two-step flash Joule heating method recovers lithium‑ion battery materials quickly and cleanly

A research team at Rice University led by James Tour has developed a two-step flash Joule heating-chlorination and oxidation (FJH-ClO) process that rapidly separates lithium and transition metals from spent lithium-ion batteries. The method provides an acid-free, energy-saving alternative to conventional recycling techniques, a breakthrough that aligns with the surging global demand for batteries used in electric vehicles and portable electronics.

Published in Advanced Materials, this research could transform the recovery of critical battery materials. Traditional recycling methods are often energy intensive, generate wastewater and frequently require harsh chemicals. In contrast, the FJH-ClO process achieves high yields and purity of lithium, cobalt and graphite while reducing energy consumption, chemical usage and costs.

“We designed the FJH-ClO process to challenge the notion that battery recycling must rely on acid leaching,” said Tour, the T.T. and W.F. Chao Professor of Chemistry and professor of materials science and nanoengineering. “FJH-ClO is a fast, precise way to extract valuable materials without damaging them or harming the environment.”

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