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Category: physics

Programmable metasurface turns keyboard commands into dynamic holograms in milliseconds

Metasurfaces are ultrathin optical components engineered with arrays of nanoscale structures that can control light in ways that are difficult for conventional optics. Unlike traditional optical components, which typically rely on their shape and thickness, metasurfaces manipulate light using carefully designed nanostructures patterned on a flat surface.

“Active metasurfaces are extending the capabilities of flat optics by enabling optical functions to be dynamically reconfigured,” says Professor Laura Na Liu, director of the 2nd Physics Institute at the University of Stuttgart. “To tap into this potential, we need to learn how to address individual pixels within a two-dimensional metasurface at visible wavelengths.”

Researchers at the University of Stuttgart have developed an interactively addressable organic metadevice that uses electrically switchable organic materials to dynamically control light. The new platform enables every metasurface pixel to be electronically controlled independently, allowing user commands to be translated directly into dynamic holographic images.

How physics and mathematical modeling help us make better clothes

A new paper in the journal Nature Physics offers insights into the physics of liquid droplets—and while many people may not appreciate the mathematical accomplishment, they will benefit from the athletic wear and raincoats it makes possible. The recent article, “Tricky Tension,” explores the intersection of physics and textiles and how wetting is influenced by the structure of tiny individual liquid droplets.

In physics, the cohesive force between two phases is called surface tension. This allows small insects to walk on water.

In a three-phase system—where gas, liquid and solid objects all interact—there is a less-understood phenomenon called the line tension of a liquid droplet. This refers to the force acting at the boundary where the liquid droplet, the air and the solid surface on which the droplet sits all meet. Learning more about the mechanics of droplets on solid surfaces, known as sessile droplets, is important for understanding the wetting and drying of textiles, especially for very small droplets.

How Gravity from Entropy theory connects the second law of thermodynamics with the emergence of cosmic structure

A new study by Queen Mary University of London mathematician Professor Ginestra Bianconi proposes a new perspective on one of the deepest questions in modern physics: How can the universe become increasingly structured and complex while still obeying the second law of thermodynamics?

Einstein famously stated that “The second law of thermodynamics occupies a unique position among the laws of Nature,” reflecting his conviction that it is among the most fundamental principles of physics and unlikely to be overthrown. The second law states that the total entropy of an isolated system tends to increase over time, a principle often associated with the growth of disorder.

This presents a long-standing puzzle in cosmology. The early universe is generally believed to have existed in a low-entropy state and to evolve toward states of higher entropy. Yet over cosmic history, the universe has also given rise to increasingly complex structures, including galaxies, stars, planets and ultimately life itself. Reconciling the emergence of such ordered structures with the relentless increase of entropy remains an open challenge.

Scientists Solve The 40-Year Mystery of a Giant Structure Towering Over The Milky Way

Scientists have just discovered the Milky Way’s equivalent of a giant fake mustache.

For four decades, astronomers have puzzled over a giant loop apparently ballooning out of the center of the Milky Way.

Known as the Galactic center lobe (GCL), the structure has been blamed on everything from the aftermath of a supernova to an ancient eruption from the Milky Way’s core – so many competing explanations that one team described it as “a Rorschach test for Galactic astrophysics.”

Most Of The Universe Is Missing And We Don’t Know Why

Everything you see, touch and are built from is a minority of what the universe is actually made of, and the closer physics looks at the rest, the less the picture holds together. Over the next 3 hours, we move outwards through that problem: from the 85 per cent of matter that is invisible, to the visible matter whose textbook description is admittedly unfinished, to a dimension of space that scientists are now building by hand in a lab, and finally to the question of whether we can ever truly know what reality is made of at all.

Watch our interview with Dark Energy Researcher, Tessa Baker: • What If Dark Energy Comes From Space-Time…

00:00:00 Intro.
00:01:39 We May Be Wrong About Dark Matter.
00:31:38 Frank Close: We Were Wrong About Matter.
01:39:09 Scientists Build A Window Into The Fourth Dimension.
02:01:37 Sean Carroll: We May Never Understand Reality.

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A new ‘library’ for Feynman integrals

Theoretical physicists at Johannes Gutenberg University Mainz (JGU) have developed a new method of ordering Feynman integrals. This critical step in making theoretical predictions for high-energy precision measurements has posed a major computational bottleneck until now.

Scientists in the research group of Professor Stefan Weinzierl from the PRISMA⁺⁺ Cluster of Excellence propose a solution to this longstanding challenge in new articles published in Physical Review Letters and Physical Review D. By ordering the integrals according to their intrinsic geometric properties, they can speed computation times by a factor of about 1,000.

“Feynman integrals are mathematical expressions that researchers must evaluate to make precise predictions,” said Weinzierl. “These are the first pillars for precise predictions for measurements at facilities like the Large Hadron Collider in Switzerland.” The number of these integrals varies from process to process, with some processes needing up to one million.

Single fission experiment maps excess gamma rays from more than a dozen unstable nuclei

In a single experiment, physicists have measured the “excess” emission of high-energy gamma rays from more than a dozen heavy, unstable atomic nuclei. Mapping the gamma-ray emissions of so many isotopes produced in nuclear fission marks an important step toward a better understanding of one of the key phenomena in modern nuclear physics: the fission process itself.

Why do excited heavy nuclei produced in fission appear to emit excessive amounts of particularly energetic gamma radiation? New clues to this long-standing question have emerged from an international experiment conducted at the GANIL accelerator facility in Caen, northern France. Here, a beryllium-9 target was bombarded with uranium-238 ions, producing unstable curium-247 nuclei that rapidly underwent fission into two lighter fragments.

By combining unique experimental techniques, researchers were able—for the first time within a single experiment—to collect data on high-energy gamma-ray emissions from more than a dozen heavy, unstable isotopes. The first results of the experiment, to which the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Krakow made a significant contribution, have just been published in Physics Letters B.

‘Smaller than the tiniest scale in nature’: Physicists made a black hole out of light and used it to test Stephen Hawking’s elusive radiation theory

Scientists made a breakthrough discovery about the physics of Hawking radiation by making a miniature black hole out of light in the laboratory.

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