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Category: physics – Page 9

‘Manu jumping’: The physics behind making humongous splashes in the pool

Whether diving off docks, cannonballing into lakes or leaping off the high board, there’s nothing quite like the joy of jumping into water.

Olympic divers turned this natural act into a sophisticated science, with the goal of making a as small as possible. But another sport looks for just the opposite: the extreme maximum splash, one as high, wide and loud as possible.

Welcome to the world of “manu jumping.” Although not a familiar term in the United States, manu jumping is beloved throughout New Zealand. The sport originated in the Māori community, where popping a manu is a way of life. There, manu jumpers leap from bridges, wharves and diving platforms to make the giant splashes.

Optical technique detects ultra-weak atomic motion in crystals with high precision

A team of researchers from TU Dortmund University, the University of Paderborn, and the University of Nottingham has developed a new optical method to detect ultra-weak atomic motion. Their experiment performed in Dortmund has demonstrated unprecedented sensitivity of the detection of atomic motion in crystals by exploiting light interference.

The findings, recently published in Nature Materials, open new ways for studying ultrafast processes in materials.

Precise optical measurements rely on interferometers, where the beam probing a distance of interest interferes with a reference beam traveling a fixed path. This allows for assessing the path length difference of the two beams with high precision. A striking example is gravitational interferometers, which detect induced by a distant event in the universe, such as the collision of black holes.

Roses Offer Mechanical Clues for Shape-Shifting Materials

To validate these simulated results, PhD student Omri Cohen fabricated a series of disks from two polymer layers. The lower layer was patterned with a regular matrix and the upper one consisted of thin lines radiating out from the center. When the disks were heated and then cooled again, the matrix layer remained the same, while the upper layer contracted by a varying amount along the radial direction. This difference induced a curvature in the disk, and the team was able to replicate the simulated series of shape transitions by varying the curvature and thickness of the disks.

Further analysis shows that the formation of each cusp acts as a focal point for the stresses that accumulate in the petal. In older petals this localized concentration of stress inhibits growth around the cusps, producing a concave distortion on the rounded edge of the petal. “This completes a nice feedback cycle,” explains Sharon. “Simple growth first generates Mainardi-Codazzi-Peterson incompatibility, leading to a mechanical instability that forms cusps. These cusps then focus the stress, which affects the further growth of the tissue.”

Understanding the mechanical mechanisms that alter the shape of rose petals as they grow could inform the design of self-shaping materials and structures for applications like soft robotics and deployable spacecraft. “The idea is to program internal forces to enable the material to shape itself, and this work offers a new strategy for creating more localized shaping,” explains Benoît Roman of ESPCI ParisTech, an expert in shape-changing materials. “But the real value of this study is that it provides a perfect example of using physics to uncover and describe a deep and general phenomenon.”

Harnessing gradient doping boosts end-pumped Nd: YAG laser performance

In recent research published in Optics & Laser Technology and Infrared Physics & Technology, a research team led by Prof. Cheng Tingqing at the Hefei Institutes of Physical Science of the Chinese Academy of Sciences has introduced a novel low-thermal-effect gradient-doped crystal to tame thermal effects and improve the brightness of high-power end-pumped Nd: YAG lasers.

Traditional end-pumped solid-state lasers rely on uniformly doped crystals, which develop significant temperature gradients and thermal stresses under high pump power due to the axial absorption decay of pump power. These effects not only limit maximum pump power, but also degrade beam quality and conversion efficiency.

In this study, the researchers devised a numerical model for crystals whose neodymium concentration gradually increases along the rod, providing a theoretical basis for optimizing the concentration distribution and growth of novel gradient-doped crystals.

Photonic chip design offers simpler solution for one-way light flow in optical circuits

To improve photonic and electronic circuitry used in semiconductor chips and fiber optic systems, researchers at the McKelvey School of Engineering at Washington University in St. Louis tinkered with the rules of physics that govern the movement of light over time and space. They have introduced a new way to manipulate light transmission, opening possibilities for advanced optical devices.

Their method causes a “mirror-flip of the system,” said Lan Yang, the Edwin H. & Florence G. Skinner Professor of electrical and and senior author of the research, now published in Science Advances.

Using parity-time (PT) symmetric photonic waveguides, they can manipulate the light waves to “reverse time” so the system behaves the same as before, Yang added.

The Great Cosmic Wiggle: Quasars Reveal Gravity’s Hidden Rhythm

Gravitational waves are constantly washing over Earth, but an astrophysicist aims to capture them in an entirely new way—by watching distant quasars appear to wiggle due to spacetime distortions.

Using data from the Gaia satellite, he’s searching for three-dimensional effects that previous techniques might have missed.

Exploring a new method to detect gravitational waves.

30-year Mystery of Dissonance in The ‘Ringing’ of Black Holes Explained

A scientist from Tokyo Metropolitan University has solved the longstanding problem of a “dissonance” in gravitational waves emitted by a black hole.

Using high precision computing and a new theoretical physics framework, it was discovered that it was caused by a resonance between a pair of distinctive “modes” i.e. different ways in which a black hole can “ring.” The phenomenon offers new insights into the nascent field of black hole spectroscopy.

The research is published in the journal Physical Review Letters.

Could gravity be evidence that the universe is a computer simulation? My new study suggests why this might be so

We have long taken it for granted that gravity is one of the basic forces of nature – one of the invisible threads that keeps the universe stitched together. But suppose that this is not true. Suppose the law of gravity is simply an echo of something more fundamental: a byproduct of the universe operating under a computer-like code.

That is the premise of my latest research, published in the journal AIP Advances. It suggests that gravity is not a mysterious force that attracts objects towards one another, but the product of an informational law of nature that I call the second law of infodynamics.

It is a notion that seems like science fiction – but one that is based in physics and evidence that the universe appears to be operating suspiciously like a computer simulation.

Butterflies hover differently from other flying organisms, thanks to body pitch

Butterflies’ flight trajectories often appear random or chaotic, and compared with other hovering insects, their bodies follow seemingly mysterious, jagged, jerking motions.

These unique hovering patterns, however, can potentially provide critical design insights for developing micro-aerial vehicles (MAVs) with flapping wings. To help achieve these applications, researchers from Beihang University studied how butterflies use aerodynamic generation to achieve hovering. They discuss their findings in Physics of Fluids.

“Hovering serves as an essential survival mechanism for critical behaviors, including flower visitation and predator evasion,” said author Yanlai Zhang. “Elucidating its aerodynamic mechanisms provides fundamental insights into the evolutionary adaptations of butterflies’ flight kinematics.”

Researchers observe time crystal in a spin maser system

Time crystals represent a new phase of matter proposed by Frank Wilczek, the Nobel laureate of Physics in 2004; they can break original time-translation symmetry and create new time oscillations spontaneously.

Recently, a joint research team from the National Time Service Center (NTSC) of the Chinese Academy of Sciences and Shanghai Jiao Tong University observed a time crystal in a maser system.

The results are published in Communications Physics.