Phys.org Physics

• Mott and Kondo insulators—how external stimuli can modify electronic energy bands

  A study from the Research Center for Materials Nanoarchitectonics (MANA) has uncovered a theoretical mechanism showing how the electronic band structures of strongly correlated insulators can be reshaped by spin and charge perturbations, opening up new possibilities for electronics with tunable band structures.

• Scientists unveil universal aging mechanism in glassy materials

  "Glass" has a unique and distinct meaning in physics—one that refers not just to the transparent material we associate with window glass. Instead, it refers to any system that looks solid but is not in true equilibrium and continues to change extremely slowly over time. Examples include window glass, plastics, metallic glasses, spin glasses (i.e., magnetic systems), and even some biological and computational systems.

• Smart fluorescent molecules provide cheaper path to sharper microscopy images

  Multiphoton microscopy is used in biomedical research to study cells and tissues. Today, so-called two-photon microscopy is used to study processes within cells, but the technique has limitations in terms of image resolution. Four-photon microscopy provides images with higher resolution. However, such instruments are very expensive and, when studying biological material, the powerful laser light required can damage samples.

• 3D-printed 'plug' links fiber optics to photonic chips with low loss

  Physicists and chemists at Heidelberg University have realized a photonic microchip that is driven by light just as easily as electronic components via a "plug." Their development could serve as the basis for fast and cost-effective production of photonic integrated systems that are of great importance for implementing innovative computing and communications systems.

• Laser-within-a-laser delivers MeV X-ray radiography in picoseconds

  Lawrence Livermore National Laboratory's National Ignition Facility (NIF) is the hottest place on Earth for the briefest of moments during an experiment. Now, it can be one of the brightest places thanks to the Advanced Radiographic Capability (ARC), NIF's laser-within-a-laser. How this is possible and how it's measured is detailed in a paper in Physics of Plasmas titled "Development and scaling of MeV X-ray radiography at NIF-ARC."

• Superfluids emerge in 2D moiré crystal formed from time, study predicts

  Conventional crystals are materials in which atoms arrange themselves in repeating spatial patterns. Time crystals, on the other hand, are phases of matter characterized by repeating motions over time without constantly heating up, breaking a physical rule known as time-translation symmetry.

• Simulations show a path to 'ideal glass' with crystal-like entropy

  The types of glass that we encounter in everyday life, such as window glass or smartphone screens, are disordered solids. This means that they consist of particles locked in place, like those in solids, but arranged randomly, similarly to how they would be in a liquid.

• Heavier hydrogen makes silicon T centers shine brighter for quantum networks

  Quantum technologies, computers or other devices that operate leveraging quantum mechanical effects, rely on the precise control of light and matter. Over the past decades, quantum physicists and material scientists have been trying to identify systems that can reliably generate photons (i.e., light particles) and could thus be used to create quantum technologies.

• Dynamical freezing can protect quantum information for near-cosmic timescales

  Preserving quantum information is key to developing useful quantum computing systems. But interacting quantum systems are chaotic and follow laws of thermodynamics, eventually leading to information loss. Physicists have long known of a strange exception, called dynamical freezing, when quantum systems shaken at precisely tuned frequencies evade these laws. But how long can this phenomenon postpone thermodynamics?

• InN thin films show transient Pauli blocking for broadband ultrafast optical switching

  Recent decades have witnessed rapid advancements in high-intensity laser technology. The combination of laser irradiation and novel materials is opening exciting avenues for the design of functional materials and devices. Semiconductors are ideal platforms for generating laser-driven functionalities because they can exhibit novel features such as ultrafast optical transparency. This effect arises from electronic occupation redistribution driven by ultrafast excitation, which manifests as a phenomenon called transient Pauli blocking.

• Cooling without gases: Molecular design brings solid-state cooling closer to reality

  Some solid materials can cool down or heat up when pressure is applied or released. This behavior enables cooling and heating technologies that do not rely on climate-damaging refrigerant gases. In practice, however, a major obstacle remains: many materials behave differently during heating and cooling, which makes their response difficult to use reliably in real devices. In a study published in the journal Communications Materials, researchers investigate a solid material known for its exceptionally large cooling/heating response (thermal response) under pressure and ask a simple question: can this response be made more reliable? They show that a very small change in composition leads to a clear improvement and use neutron experiments to explain why this improvement occurs.

• Metasurface-based SLM could enhance AR, VR and LiDAR performance

  Many cutting-edge technologies, ranging from augmented reality (AR) and virtual reality (VR) to LiDAR (light detection and ranging) systems, rely on components that enable the precise control of light. These components include so-called spatial light modulators (SLMs), systems that dynamically adjust the position of a light wave within its cycle (i.e., phase), as well as its amplitude or direction across several pixels.

• Beam-spin asymmetry study puts proton models to the test

  Getting an up-close view of life at the cellular level can be as simple as placing onion skin under a microscope and adjusting the knobs. Peering deeper, into the heart of the atoms within, isn't as easy. It requires peeling through layers of particle accelerator data to shed light on protons, neutrons and the subatomic processes at play.

• The screech of peeling sticky tape conceals a rapid train of tiny shockwaves, ultrafast imaging shows

  A new experiment has uncovered the mechanism responsible for the screeching sound made by peeling sticky tape. Using a combination of ultrafast imaging and synchronized acoustic recordings, Sigurdur Thoroddsen and colleagues at King Abdullah University of Science and Technology have shown that the noise is produced by a rapid train of tiny shockwaves, released through a specialized form of stick–slip motion. The research is published in Physical Review E.

• Matching vibrations is all it takes to shut down superconductivity in a nearby crystal

  The world is never really at rest. Even in a vacuum near ultracold temperatures where all classical motion should come to a halt, you'll find quantum fluctuations. In thin, two-dimensional materials, these include random vibrations that can alter electromagnetic fields, a feature that theorists have posited could be quite useful for modifying materials.

• What does it mean to compute? Framework maps hidden computations running inside natural dynamic systems

  Some computers are easy to spot. Artificial, human-built computers like those found in smartphones and laptops are abstract dynamic systems with observable computational elements like input, output, energy cost, and logical processes. Other computers aren't so readily recognized.

• Why you can't tie knots in four dimensions

  We all know we live in three-dimensional space. But what does it mean when people talk about four dimensions? Is it just a bigger kind of space? Is it "space-time," the popular idea which emerged from Einstein's theory of relativity?

• From theory to safety: New model predicts how combustion scenarios unfold

  Researchers from Skoltech have published a paper in the journal Physica D: Nonlinear Phenomena presenting an analysis of steady propagating combustion waves—from slow flames to supersonic detonation waves. The study relies on the authors' mathematical model, which captures the key physical properties of complex combustion processes and yields accurate analytical and numerical solutions. The findings are important for understanding the physical mechanisms behind the transition from deflagration to detonation, as well as for developing safer engines, fuel combustion systems, and protection against unwanted explosions in industrial settings.

• Rydberg atoms detect clear signals from a handheld radio

  For the first time, a team of US researchers has used sensors containing highly excited Rydberg atoms to detect signals from an ordinary handheld radio. Through a careful approach to demodulating the incoming signals, Noah Schlossberger and colleagues at the National Institute of Standards and Technology (NIST) were able to recover audio encoded in multiple public radio channels, with promising implications for everyday uses in consumer electronics. The research has been published in Physical Review Applied.

• Energy loss triggers quantum thermal Hall-like effect at macroscopic scale

  In many quantum materials—materials with unusual electrical and magnetic properties driven by quantum mechanical effects—electrons can organize themselves into Landau levels. Landau levels are essentially quantized energy states that form when charged particles move in a magnetic field.

• Tackling industry's burdensome bubble problem

  In industrial plants around the world, tiny bubbles cause big problems. Bubbles clog filters, disrupt chemical reactions, reduce throughput during biomanufacturing, and can even cause overheating in electronics and nuclear power plants. MIT Professor Kripa Varanasi has long studied methods to reduce bubble disruption.

• A puddle that jumps: What bubble bursts reveal about water on lotus-like surfaces

  Water droplets have a unique ability: They can leap from a surface on their own. This can happen for a variety of reasons, such as when a surface repels water or when heat is involved, such as a water or oil droplet skittering across a hot pan.

• A world first at the microscopic scale: Metamaterials that can shrink and expand on their own

  Leiden physicists Daniela Kraft and Julio Melio have created soft structures that can take on different shapes without any external drive in their lab. They present their research on microscale metamaterials in Nature—a breakthrough that opens the door to smart, reconfigurable materials and microscopic robots.

• A robust new telecom qubit identified in silicon

  Quantum technologies are anticipated to transform computing, communication, and sensing by harnessing the unusual behavior of matter at the atomic scale. Translating quantum's promise into practical devices will require physical systems that have desirable quantum properties and can be easily manufactured. Silicon, the material behind today's computer chips, is highly attractive as a platform because it plays to the strengths of the trillion-dollar semiconductor industry that has already been built. Identifying quantum building blocks—qubits—in silicon is, therefore, an important frontier research area.

• Ion bombardment triggers a reliable quantum switch in tantalum disulfide crystals

  When you toss a coin, you put it into a higher-energy state until it falls back down again. It can then end up in one of two possible states: heads or tails. No matter which state the coin was in before, after the toss both outcomes are equally likely. A team at TU Wien has analyzed a quantum system that also has two equivalent ground states. By supplying energy through ion bombardment, this state can be changed.