Showing posts with label knots. Show all posts
Showing posts with label knots. Show all posts

Thursday, April 3, 2025

Captain Tying Knots


With all the topological mention these days, we have to ask - whatever happened to knots?

String figures shed light on cultural connections and the roots of mathematical reasoning
Dec 2024, phys.org

String figure games (like cat's cradle or jacob's ladder?) involve the manipulation of a loop of string with the fingers to create complex patterns. The researchers analyzed 826 string figures from 92 cultures around the world. They found 83 recurring designs. The results show that certain figures are globally prevalent. In certain cases, this suggests ancient cultural origins potentially extending back millennia. 

The researchers applied mathematical knot theory to develop a computational method to create a DNA-like symbolic representation of each string figure. This enables the cross-cultural comparison of string figures and the construction of their "family tree."

via University of Helsinki, Aarhus University, National Museum of Denmark and Seattle University: Roope O. Kaaronen et al, A global cross-cultural analysis of string figures reveals evidence of deep transmission and innovation, Journal of The Royal Society Interface (2024). DOI: 10.1098/rsif.2024.0673

Image credit: Fingers, not bad, not good enough. AI Art - Let Go - 2025

Wednesday, July 17, 2024

Topological Knot Gobbler


Watching two squirrels chase each other up, down, and all around a tree, a revelation came to me - why would we expect the "spatial organization" part of the brain to be limited to two-dimensional hexagonal tiles? These animals spend most of their time running around on trees, not on the ground. Their world is not flat. Their "surface" is a constantly curving tree trunk. Insects, same thing. For them, the basis of spatial dimension is not a flat plane, it's a curved plane. Up, down, and gravity in general are not constants. The default is a curved surface, not the other way around. And that's the more flexible model of the two, so why wouldn't it be the base model?

The idea that the spatial-brain is 2-D is a very human-based bias. It shouldn't be hard to accept the fact that not long after the hexagonal grid brain model was confirmed ("grid cells" 2005), the hyperdimensional toroid model came on the scene (2022). In other words, the brain thinks the landscape is a toroid. 

What's happening in the rapid upheaval of our understanding of space (quantum gravity, Moiré lattices etc.) might be less disorienting if we considered this. I'm not sure how we do this, re-wiring our brains to perform in topological space, but I bet psychedelic mushrooms would help. Or DMT:
The Hyperbolic Geometry of DMT Experiences at the Harvard Science of Psychedelics Club in the year 2020, with Andrés Gómez Emilsson from the Qualia Research Institute

And finally, aside from the spatial implications, topology seems to be a fertile area of study for discoveries on the nature of all things quantum, as seen below. 



Team discovers thousands of new transformable knots
Sep 2023, phys.org

They discovered thousands of new transformable knots including three novel shapes that the humble figure-eight knot can assume, doubling the number documented to date in scientific literature.

via EPFL Ecole Polytechnique Federale de Lausanne Geometric Computing Laboratory: Michele Vidulis et al, Computational Exploration of Multistable Elastic Knots, ACM Transactions on Graphics (2023). DOI: 10.1145/3592399


Molecular knots, left and right: How molecules form knots
Oct 2023, phys.org

They created a computational model for molecular knots, and mostly for optical topology.

via Max Planck Institute for Polymer Research in Mainz, Germany: Yani Zhao et al, Can Polymer Helicity Affect Topological Chirality of Polymer Knots?, ACS Macro Letters (2023). DOI: 10.1021/acsmacrolett.2c00600


Topologically structured light detects the position of nano-objects with atomic resolution
May 2023, phys.org

Just superoscillatory light, optical metrology, and topologically structured light.

via University of Southampton and Nanyang Technological University: Tongjun Liu et al, Picophotonic localization metrology beyond thermal fluctuations, Nature Materials (2023). DOI: 10.1038/s41563-023-01543-y


Researchers demonstrate that quantum entanglement and topology are inextricably linked
Jan 2024, phys.org

Skyrmion topology to be specific:

"We achieved this experimental milestone by entangling two identical photons and customizing their shared wave-function in such a way that their topology or structure becomes apparent only when the photons are treated as a unified entity" 

In the realm of condensed matter physics, skyrmions are highly regarded for their stability and noise resistance. 

"Our work presents a paradigm shift: the topology that has traditionally been thought to exist in a single and local configuration is now nonlocal or shared between spatially separated entities" says Ornelas.

Expanding on this concept, the researchers utilize topology as a framework to classify or distinguish entangled states. They envisage that "this fresh perspective can serve as a labeling system for entangled states, akin to an alphabet," says Dr. Isaac Nape, a co-investigator.

via Structured Light Laboratory in the School of Physics at the University of the Witwatersrand in South Africa, string theorist Robert de Mello Koch from Huzhou University in China, previously from Wits University: Pedro Ornelas et al, Non-local skyrmions as topologically resilient quantum entangled states of light, Nature Photonics (2024). DOI: 10.1038/s41566-023-01360-4

AI Art - Pink Healthy Ovary - 2024

Quantum physicists develop robust and ultra-sensitive topological quantum device
Jan 2024, phys.org

They were the first to realize the topological skin effect on a microscopic scale in a semiconductor material. This quantum phenomenon was initially demonstrated at a macroscopic level three years ago—but only in an artificial metamaterial, not a natural one. This is therefore the first time that a tiny, semiconductor-based topological quantum device that's both highly robust and ultra-sensitive has been developed.

via Würzburg-Dresdner Exzellenzcluster for Complexity and Topology in Quantum Matter: Kyrylo Ochkan et al, Non-Hermitian topology in a multi-terminal quantum Hall device, Nature Physics (2024). DOI: 10.1038/s41567-023-02337-4


Classifying quantum secrets: Pendulum experiment reveals insights into topological materials
Mar 2024, phys.org

Interesting analog (quantum analog)

They built an array of 50 coupled pendula, with string lengths that slightly varied from one pendulum to the other. The strings of each neighboring pair of pendula were connected at a controlled height, such that each one's motion would affect its neighbors' motion.

The system obeyed Newton's laws of motion, but the precise lengths of the pendula and the connections between them created a magical phenomenon: Newton's laws caused the wave of the pendula's motion to approximately obey Schrödinger's equation. Therefore, the motion of the pendula, which is visible in the macroscopic world, reproduces the behaviors of electrons in periodic systems such as crystals.

via the Nuclear Research Center, Department of Biomedical Engineering, School of Mechanical Engineering, and School of Physics and Astronomy at Tel Aviv University: Izhar Neder et al, Bloch oscillations, Landau–Zener transition, and topological phase evolution in an array of coupled pendula, Proceedings of the Nation


'Tube map' around planets and moons made possible by knot theory
Apr 2024, phys.org

Knot Theory

In recent decades, space missions have increasingly relied on the ability to change the course of a satellite's path through space without using fuel by finding 'heteroclinic connections', usually calculated by using vast computing power to churn through one option after another or by making an 'intelligent guess' and then investigating it further. A new technique uses an area of math called knot theory to quickly generate rough trajectories.

via University of Surrey: Danny Owen et al, Applications of knot theory to the detection of heteroclinic connections between quasi-periodic orbits, Astrodynamics (2024). DOI: 10.1007/s42064-024-0201-0


Wednesday, January 13, 2021

Origamibots and Trefoil Knots - Messengers of the Future


Quantum origami and light knots, we just can't get enough.

image credit: Microphoto of a human hair by Robert Vierthaler for the the Nikon Small World 2020 competition.

Origami microbots - Centuries-old artform guides cutting-edge advances in tiny machines
Aug 2020, phys.org

Origamibots.

They change shape depending on what they need to do. It's more efficient, and they can now be made smaller, faster, and more precise. It also sounds like it's covered in a thin layer of gold, then polymer, and this allows heat to be applied and to travel across the surface of the microbot, controlling its folds with hots and colds. 

via University of Michigan, Yi Zhu et al, Elastically and Plastically Foldable Electrothermal Micro‐Origami for Controllable and Rapid Shape Morphing, Advanced Functional Materials (2020). DOI: 10.1002/adfm.202003741

This is a Kressling pattern, courtesy of NOVA

Building mechanical memory boards using origami
Aug 2020, phys.org

It's an origami mechanical memory board. It's called a Kresling-inspired mechanical switch, or KIMS. Kressling pattern origami are ones that can flip between two shapes, depending on how you configure them, and this one is configured by vibrating a platform on which it rests. The vibration activates a mechanical switch.
 
This is just fucking crazy. Imagine making origami metamaterial that have properties like an electric circuit. It would be like a 3D computer where the transistors are an integral part if the structure, instead of being in a central location, they're all over, like cells in a body.

Framed Trefoil Knot, University of Ottawa

Classified knots - Researchers create optical framed knots to encode information
Oct 2020, phys.org

More origami people. Made of lights, of course.

Optical framed knots distributing secret cryptographic keys, providing a platform for topological quantum computations, they say.

Framed knots are when you take a strip of paper and try to tie a knot with it, kind of like M.C.Escher's mobius strip.

It has to do with light beams, structured light beams, using beam-shaping techniques that can actually shape the light beam to have knots in it? Cryptographic code knots sounds like a great idea.

Hugo Larocque et al, Optical framed knots as information carriers, Nature Communications (2020). DOI: 10.1038/s41467-020-18792-z

Wednesday, January 4, 2017

On Knots

Captain Tying Knots

You've heard of string theory. What about knot theory?
Feb 2016, phys.org

Tait Flyping Conjecture: the basis for a periodic table of knots in which hydrogen would be the "unknot" — the unknotted circle — and heavier elements would be knots whose filaments crossed over themselves an ever-higher number of times.

A new mathematical model predicts a knot's stability
Jan 2020, phys.org