Phys.org Physics

• 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.

• The physics of sneaker squeaks: High-speed imaging shows how they arise from supersonic detachment pulses

  Basketball shoes on a gym floor, bicycle brakes in need of a tune-up, or the squeal of tires are everyday examples of squeaking sounds. Such sounds have long been attributed to stick-slip friction, or a cycle of intermittent sticking and sliding between surfaces. While this framework explains many rigid-on-rigid systems such as door hinges, it does not fully capture the physics of soft-on-rigid interfaces, like shoes on a floor.

• A protocol to realize near-perfect atom-photon entanglement

  Quantum technologies, devices and systems that operate leveraging quantum mechanical effects, could tackle some tasks more reliably and efficiently than any classical technology could. In recent years, some researchers have been trying to realize quantum networks to scale up the size of quantum computers, which essentially consist of several connected smaller quantum processors.

• Quantum effect could power the next generation of battery-free devices

  A new study has revealed how tiny imperfections and vibrations inside a promising quantum material could be used to control an unusual quantum effect, opening new possibilities for smaller, faster, and more efficient energy-harvesting devices.

• When light 'thinks' like the brain: The connection between photons and artificial memory

  An international study has revealed a surprising connection between quantum physics and the theoretical models underlying artificial intelligence. The study results from a collaboration between the Institute of Nanotechnology of the National Research Council (Cnr-Nanotec), the Italian Institute of Technology (IIT), and Sapienza University of Rome, together with international research institutions. The research paper was published recently in the journal Physical Review Letters.

• Physicists watch light drift in quantized steps for the first time

  In physics, the classical "Hall effect," discovered in the late 19th century, describes how a transverse voltage is generated when an electric current is exposed to a perpendicular magnetic field. Simply put, the magnetic field causes the electrons, which are negatively charged, to drift sideways, creating a negative charge on one edge of the conducting strip and a positive charge on the opposite side.

• AI develops easily understandable solutions for unusual experiments in quantum physics

  Researchers at the University of Tuebingen, working with an international team, have developed an artificial intelligence that designs entirely new, sometimes unusual, experiments in quantum physics and presents them in a way that is easily understandable for researchers. This includes experimental setups that humans might never have considered. The new AI doesn't just create a single design proposal; instead, it writes computer code that generates a whole series of physical experiments, that is, groups of experiments with similar outputs. The study has been published in the journal Nature Machine Intelligence.

• Clearing the path for turbulence-free quantum communication

  A University of Ottawa team has developed a new way to protect free-space quantum key distribution (QKD) from atmospheric turbulence, one of the main causes of distortion and errors when sending quantum information through air. Their paper, "All-optical turbulence mitigation for free-space quantum key distribution using stimulated parametric down-conversion," appears in the journal Optica.

• Electrical control of magnetism in 2D materials promises to advance spintronics

  Conventional electronics process information leveraging the electrical charge of electrons. Over the past few decades, some electronics engineers have been exploring the potential of a different type of device that instead processes and stores data exploiting the intrinsic magnetic moment (i.e., spin) of electrons.