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Floquet Chern insulators based on nonlinear photonic crystals achieved

Over the past few years, engineers and material scientists have been trying to devise new optical systems in which light particles (i.e., photons) can move freely and in useful ways, irrespective of defects and imperfections. Topological phases, unique states of matter that are not defined by local properties, but by non-local and global features, can enable the robust movement of photons despite material defects.

Researchers at the University of Pennsylvania and University of California-Santa Barbara recently demonstrated the realization of Floquet Chern insulators, materials in which the periodic application of an oscillating light field or other external fields give rise to a unique topological phase, in a nonlinear photonic system. The insulators presented in their paper, which was published in Nature Nanotechnology, are based on nonlinear photonic crystals, materials with repeating patterns that can control the and respond differently to light of different intensities.

“Topological photonics explores photonic systems that exhibit robustness against defects and disorder, enabled by protection from underlying ,” wrote Jicheng Jin, Li He and their colleagues in their paper. “These phases are typically realized in linear optical systems and characterized by their intrinsic photonic band structures. We experimentally study Floquet Chern insulators in periodically driven nonlinear photonic crystals, where the topological phase is controlled by the polarization and the frequency of the driving field.”

Mapping RNA-protein ‘chats’ could uncover new treatments for cancer and brain disease

Bioengineers at the University of California San Diego have developed a powerful new technology that can map the entire network of RNA-protein interactions inside human cells—an achievement that could offer new strategies for treating diseases ranging from cancer to Alzheimer’s.

RNA-protein interactions regulate many essential processes in cells, from turning genes on and off to responding to stress. But until now, scientists could only capture small subsets of these interactions, leaving much of the cellular “conversation” hidden.

“This technology is like a wiring map of the cell’s conversations,” said Sheng Zhong, professor in the Shu Chien-Gene Lay Department of Bioengineering at the UC San Diego Jacobs School of Engineering, who led the study published in Nature Biotechnology.

Silver-nanoring coating points to ‘self-regulating’ smart windows—without power or tinting

A new Danish research breakthrough could make buildings far more energy-efficient in the future. Researchers from Aarhus University’s Interdisciplinary Nanoscience Center (iNANO) have developed a light-responsive hybrid material based on so-called silver nanorings that automatically responds to solar intensity and regulates how much heat penetrates through windows.

The microscopic silver rings increasingly block near-infrared light as sunlight becomes stronger—without making the glass less transparent.

The technology functions without the use of power, sensors, or electronics—and could potentially be applied as a window coating in, for example, and modern residential buildings where large glass areas are common and heat radiation from the sun can be a challenge. This makes the solution particularly relevant at a time when for cooling exceeds the need for heating in large parts of the world.

Designing random nanofiber networks, optimized for strength and toughness

In nature, random fiber networks such as some of the tissues in the human body, are strong and tough with the ability to hold together but also stretch a lot before they fail. Studying this structural randomness—that nature seems to replicate so effortlessly—is extremely difficult in the lab and is even more difficult to accurately reproduce in engineering applications.

Recently, researchers at The Grainger College of Engineering, University of Illinois Urbana-Champaign and the Rensselaer Polytechnic Institute devised a method to repeatedly print random polymer nanofiber networks with desired characteristics and use to tune the random network characteristics for improved strength and toughness.

“This is a big leap in understanding how nanofiber networks behave,” said Ioannis Chasiotis, a professor in the Department of Aerospace Engineering. “Now, for the first time, we can reproduce randomness with desirable underlying structural parameters in the lab, and with the companion computer model, we can optimize the to find the network parameters, such as nanofiber density, that produce simultaneously higher network strength, stiffness and toughness.”

Molecular qubits can communicate at telecom frequencies

A team of scientists from the University of Chicago, the University of California Berkeley, Argonne National Laboratory, and Lawrence Berkeley National Laboratory has developed molecular qubits that bridge the gap between light and magnetism—and operate at the same frequencies as telecommunications technology. The advance, published today in Science, establishes a promising new building block for scalable quantum technologies that can integrate seamlessly with existing fiber-optic networks.

Because the new molecular qubits can interact at telecom-band frequencies, the work points toward future quantum networks—sometimes called the “.” Such networks could enable ultra-secure communication channels, connect quantum computers across long distances, and distribute quantum sensors with unprecedented precision.

Molecular qubits could also serve as highly sensitive quantum sensors; their tiny size and chemical flexibility mean they could be embedded in unusual environments—such as —to measure magnetic fields, temperature, or pressure at the nanoscale. And because they are compatible with silicon photonics, these molecules could be integrated directly into chips, paving the way for compact quantum devices that could be used for computing, communication, or sensing.

AI techniques excel at solving complex equations in physics, especially inverse problems

Differential equations are fundamental tools in physics: they are used to describe phenomena ranging from fluid dynamics to general relativity. But when these equations become stiff (i.e. they involve very different scales or highly sensitive parameters), they become extremely difficult to solve. This is especially relevant in inverse problems, where scientists try to deduce unknown physical laws from observed data.

To tackle this challenge, the researchers have enhanced the capabilities of Physics-Informed Neural Networks (PINNs), a type of artificial intelligence that incorporates physical laws into its .

Their approach, reported in Communications Physics, combines two innovative techniques: Multi-Head (MH) training, which allows the neural network to learn a general space of solutions for a family of equations—rather than just one specific case—and Unimodular Regularization (UR), inspired by concepts from differential geometry and , which stabilizes the learning process and improves the network’s ability to generalize to new, more difficult problems.

Quantum key distribution method tested in urban infrastructure offers secure communications

In the era of instant data exchange and growing risks of cyberattacks, scientists are seeking secure methods of transmitting information. One promising solution is quantum cryptography—a quantum technology that uses single photons to establish encryption keys.

A team from the Faculty of Physics at the University of Warsaw has developed and tested in a novel system for quantum key distribution (QKD). The system employs so-called high-dimensional encoding. The proposed setup is simpler to build and scale than existing solutions, while being based on a phenomenon known to physicists for nearly two centuries—the Talbot effect. The research results have been published in the journals Optica Quantum, Optica, and Physical Review Applied.

“Our research focuses on quantum key distribution (QKD)—a technology that uses single photons to establish a secure cryptographic key between two parties,” says Dr. Michał Karpiński, head of the Quantum Photonics Laboratory at the Faculty of Physics, University of Warsaw.

Finding buried treasures with physics: ‘Fingerprint matrix’ method uncovers what lies beneath the sand

Can we reveal objects that are hidden in environments completely opaque to the human eye? With conventional imaging techniques, the answer is no: a dense cloud or layer of material blocks light so completely that a simple photograph contains no information about what lies behind it.

However, a between the Institut Langevin and TU Wien has now shown that, with the help of innovative mathematical tricks, objects can be detected even in such cases—using what is known as the fingerprint .

The team tested the newly developed method on metal objects buried in sand and in applications in the field of medical imaging. A joint publication on this topic has just been published in the journal Nature Physics.

Supercritical fluids once thought uniform found to contain liquid clusters

A supercritical fluid refers to a state in which the temperature and pressure of a substance exceed its critical point, where no distinction exists between liquid and gas phases. Traditionally, it has been regarded as a single, uniform phase. However, a research team at POSTECH (Pohang University of Science and Technology) experimentally demonstrated nonequilibrium phase separation within supercritical fluids by observing nanometer-sized “liquid clusters” that persist for up to one hour.

The research team led by Professor Gunsu Yun from the Division of Advanced Nuclear Engineering and the Department of Physics at POSTECH, in collaboration with Dr. Jong Dae Jang’s group at the Korea Atomic Energy Research Institute (KAERI), Professor Min Young Ha at Kyung Hee University, and Dr. Changwoo Do’s team at Oak Ridge National Laboratory (ORNL) in the U.S., experimentally verified the existence of nano-clusters that exist separately in a liquid-like state within previously considered a uniform phases.

The experiment utilized the Small-Angle Neutron Scattering (SANS) instrument at Korea’s neutron research facility, HANARO.

Meet Irene Curie, the Nobel-winning atomic physicist who changed the course of modern cancer treatment

The adage goes “like mother like daughter,” and in the case of Irene Joliot-Curie, truer words were never spoken. She was the daughter of two Nobel Prize laureates, Marie Curie and Pierre Curie, and was herself awarded the Nobel Prize in chemistry in 1935 together with her husband, Frederic Joliot.

While her parents received the prize for the discovery of natural radioactivity, Irene’s prize was for the synthesis of artificial radioactivity. This discovery changed many fields of science and many aspects of our everyday lives. Artificial radioactivity is used today in medicine, agriculture, energy production, food sterilization, industrial quality control and more.

We are two nuclear physicists who perform experiments at different accelerator facilities around the world. Irene’s discovery laid the foundation for our experimental studies, which use artificial radioactivity to understand questions related to astrophysics, energy, medicine and more.

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