Showing posts with label complexity. Show all posts
Showing posts with label complexity. Show all posts

Wednesday, December 17, 2025

Self Assortment and Superconductive Sociality


The second to last post is what I call Peak Fleck because it sounds a lot like a quantified version of what he described in his book Genesis and Development of a Scientific Fact (1930s), the book which went on to influence Kuhn's Scientific Revolution (1962), which itself introduced the word "paradigm" as we now use it. The rest of these articles are along the same lines. 


How the loss of experienced individual elephants stops knowledge transfer between generations
May 2025, phys.org

Elephants rely heavily on elder members to navigate their environments, find resources, and avoid predators. The research highlighted that the presence of older, knowledgeable individuals—especially matriarchs—improves calf survival rates and enhances group decision-making. Without these elders, populations often face long-term setbacks.

"Elders are the keepers of knowledge in elephant societies. Their loss disrupts the transmission of essential survival skills, much like losing a library in human terms. Conserving these social ties is as important as protecting their physical habitats."

via University of Portsmouth's Center for Comparative and Evolutionary Psychology: Lucy Bates et al, Knowledge transmission, culture and the consequences of social disruption in wild elephants, Philosophical Transactions of the Royal Society B: Biological Sciences (2025). DOI: 10.1098/rstb.2024.0132



Collective memory loss in herring results in 800 km shift in spawning grounds
May 2025, phys.org

Previous research has indicated that age-selective fishing targeting older fish can disrupt cultural transmission, fragmenting established migration routes.

Analysis of fisheries records, acoustic-trawl surveys, and tagging data indicated a substantial northward migration, with the center of spawning activity shifting approximately 800 km from Møre to Lofoten.

Now that a new migratory pattern has emerged, reinforced by collective migration memory, restoring historical patterns may be impossible.

via Institute of Marine Research in Norway: Aril Slotte et al, Herring spawned poleward following fishery-induced collective memory loss, Nature (2025). DOI: 10.1038/s41586-025-08983-3


The hidden mechanics of abrupt transitions: Superconducting networks show how tiny changes trigger system collapse
Jul 2025, phys.org

They're looking at interdependent superconducting networks and found a hidden spontaneous sequence of micro-scale events that gradually destabilize a system until it snaps.

When this system approaches a "critical" points, it doesn't transition smoothly from a superconducting state to a resistive one. Instead, the system lingers, for hundreds of seconds, in a long-lived intermediate phase. Then, without further prompting, it abruptly transitions into the new state. 

At the heart of this behavior is a concept known as the branching factor—a term that gained prominence during the COVID-19 pandemic. It represents the average number of new changes triggered by each event. When the branching factor is less than one, the cascade quickly dies out. If it exceeds one, the process accelerates uncontrollably.

via Bar-Ilan University, Northeastern, and CEU Vienna: Bnaya Gross et al, The random cascading origin of abrupt transitions in interdependent systems, Nature Communications (2025). DOI: 10.1038/s41467-025-61127-z


Why your friends may be more susceptible to social influence than you are
Jul 2025, phys.org

Good nuance being added here, and it's so counter-intuitive, or just plain confusing, that it should probably knock off right away most people who try to understand it. 

The Susceptibility Paradox - users' friends are more influenceable than the users themselves

"It's not just about who you are - it's about where you are in a network, and who you're connected to"

Researchers looked at two kinds of behavior on X/Twitter: influence-driven sharing, when people post something after seeing it from others in their network; and spontaneous sharing, when they post without that exposure. In influence-driven cases, people who were less likely to be influenced were often surrounded by others who were more likely to share what they saw. This mirrors the Friendship Paradox, a finding from network science that says your friends are likely to have more friends than you do.

Homophily was especially strong in influence-driven sharing. People who post because they saw others do it were often part of tight-knit circles with similar behavior.

In many cases, knowing how a user's friends behave was enough to estimate how the user would behave. Spontaneous sharing was different. When people shared content without apparent peer exposure, their decisions were harder to predict from the network alone. 

via University of Southern California Information Sciences Institute: Luca Luceri et al, The Susceptibility Paradox in Online Social Influence, arXiv (2024). DOI: 10.48550/arxiv.2406.11553

Offline interactions predict voting patterns better than online networks, finds study
Oct 2025, phys.org

Co-location explained 97% of the variance in county-level voting patterns, compared to 85%–87% for online connections and 75%–80% for residential proximity.
  • They used Meta's Data for Good program, which collates anonymized data collected from people who enabled location services on the Facebook smartphone app.
  • Colocation is defined as two people being within the same map tile less than 600×600 meters for at least five minutes.
  • The political affiliation of each person was inferred from their county of residence.
  • Data was compared with Facebook friendships and residential proximity for all U.S. counties, along with individual survey responses from 2,420 Americans regarding their offline and online social networks during the 2020 presidential election.
  • For the residential proximity measurement, the voter registrations of the closest 1,000 neighbors were used.

via University of Trento Italy: Marco Tonin et al, Physical partisan proximity outweighs online ties in predicting US voting outcomes, PNAS Nexus (2025). DOI: 10.1093/pnasnexus/pgaf308


More friends, more division: Study finds growing social circles may fuel polarization
Oct 2025, phys.org

AKA Peak Fleck

  • To measure political polarization, they used 27,000 surveys from the Pew Research Center, and 30 different surveys totaling over 57,000 respondents from Europe and the US, including the General Social Survey (US) and the European Social Survey.
  • Increasing polarization is not merely perceived - it is measurable and objectively occurring; and this increase happened suddenly between 2008 and 2010.
  • -For decades, sociological studies showed that people maintained an average of about two close friends - people who could influence their opinions on important issues."
  • "Around 2008, there was a sharp increase from an average of two close friends to four or five."
  • "When network density increases with more connections, polarization within the collective inevitably rises sharply." 
  • "This finding impressed us greatly because it could provide a fundamental explanation."
  • They refer to it as a phase change (because it's so abrupt).
  • Their explanation: "If I have two friends, I do everything I can to keep them—I am very tolerant towards them. But if I have five and things become difficult with one of them, it's easier to end that friendship because I still have 'backups.' I no longer need to be as tolerant."
"More and more people are clearly aligning themselves with one political camp rather than holding a mixture."

This sounds like Fleck's description, of how the two sides get bigger and stronger and more concentrated until one wins. (He uses the developemnt of the scientific understanding of Syphilis among scientists and among the public.)

via Complexity Science Hub Vienna: Thurner, Stefan, Why more social interactions lead to more polarization in societies, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2517530122.


Quantifying social avoidance: Game-based choices reflect real-world relationship patterns and network size
Apr 2025, phys.org

Instead of relying on self-reported behavior, they observed participants taking part in a "choose your own adventure" style game.

"We wanted to test the hypothesis that social avoidance can be understood as a form of navigation within an abstract social space defined by two social dimensions: 'affiliation' (e.g., warmth, friendliness) and 'power' (e.g., dominance, control). We put nearly 800 online participants into the position of having just moved to a new town, with no job, no friends and no place to live, where they had to interact with people and navigate the social situations to accomplish these goals ... Declining to share personal information with a character would reduce the affiliation in the relationship, while complying with an overbearing and direct request from a character would reduce the participant's power." They used a geometry-based approach where participants were placed on a grid defined by affiliation and power, and they measured where and how they moved on the grid.

Results - people higher in self-reported social avoidance consistently made low affiliation and low power choices in our game, as we expected, and the "social distance" participants created between characters in the game they played mirrored their real social lives as described in self-report questionnaires. Specifically, the real-world social networks of participants who created more social distance between characters were found to be smaller and less diverse.

via Icahn School of Medicine at Mount Sinai: Matthew Schafer et al, Social avoidance can be quantified as navigation in abstract social space, Communications Psychology (2025). DOI: 10.1038/s44271-025-00215-8.

Thursday, April 17, 2025

The Hofstadter Regime Converges Upon Us


AKA Fine-Tuning The Chaos Machine 

The above image is the perfect example of a moiré lattice and where it comes from. I noticed it while watching a lecture by a scientist cited below, for being the first to discover Hofstadter's Butterfly in real life. It's just the best image I've seen to explain what a moiré lattice is.

Credit: Graphene hBN Moire Lattices - taken from the presentation Bloch, Landau, and Dirac - Hofstadter's Butterfly in Graphene by Philip Kim - Kavli Inst 2018 [youtube link]

The perimeter of ignorance in science is also the front door of chaos theory. You could call it a lot of other things, most of which are listed in the tags for this post, but mostly, anything that's "too complicated" for us to understand right now, it's chaos-related. Discoveries in this field come from a bunch of different places, like interdimensional graphene, like topological operators, like epilepsy surgery.

Harnessing chaos: How the brain turns randomness into robust memory
Jan 2025, phys.org

Previous work on brain-imitating artificial intelligence systems known as neural networks suggested that injecting random fluctuations into their activity could actually improve their performance as they learned to perform a task. 

Noise appears to increase the amount of time it takes for inhibitory neuron connections with other neurons to weaken. This slowing effect in turn stabilizes neural patterns of activity related to memories, helping them persist over time.

(This whole thing makes me think very differently about background noise, and maybe even the idea of 'functional music')...

via Columbia Engineering Systems Intelligence Laboratory: Nuttida Rungratsameetaweemana et al, Random noise promotes slow heterogeneous synaptic dynamics important for robust working memory computation, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2316745122


How topology drives complexity in brain, climate and AI
Feb 2025, phys.org

Yes it does 

Transformative framework for understanding complex systems, using the new field of higher-order topological dynamics, and creating a connection between topological structures and emergent behavior. This comes from the field of information theory, and combines fusion of topology, higher-order networks, and non-linear dynamics.

via University of London: Ana P. Millán et al, Topology shapes dynamics of higher-order networks, Nature Physics (2025). DOI: 10.1038/s41567-024-02757-w

(Many body problem and higher order networks are the same thing - "interactions that extend beyond simple pairwise relationships".)

Most of us need to know: Hofstadter's butterfly (1976) was discovered before Mandelbrot coined the term "fractal" (1980), so he didn't know what to call it.

Hofstadter's butterfly: Quantum fractal patterns visualized
Feb 2025, phys.org

"Our discovery was basically an accident. We didn't set out to find this."

This is the first time Hofstadter's butterfly has been directly observed experimentally in a real material.

It was found using a moiré lattice - they were investigating superconductivity in twisted bilayer graphene, and when you hear twisted layers, you know we're also talking magic angle sandwiches. They used a scanning tunneling microscope to image moiré crystals at atomic resolution and examine their electron energy levels. The microscope works by bringing a sharp metallic tip less than a nanometer from the surface to allow quantum "tunneling" of electrons from the tip to the sample.

via Princeton University: Kevin P. Nuckolls et al, Spectroscopy of the fractal Hofstadter energy spectrum, Nature (2025). DOI: 10.1038/s41586-024-08550-2


Fitness centrality: New tool finds critical points in everything from cybersecurity to ecological conservation
Jan 2025, phys.org

The Vienna Complexity hub making waves

This approach is particularly good at finding nodes that, if removed, would isolate many other parts of the network—similar to a server failure interrupting the connection of many users in a communication network or a pump failure in a water supply network paralyzing the supply of water to districts.

Species in ecological networks, nodes in cybersecurity, roads in transportation networks. That's great. But it's people where this really has impact. Imagine trying to disable a social movement that could disturb the social fabric of a nation. You find the people, the nodes, at the center of the social network, and ... remove them, let's say. 

via Complexity Science Hub Vienna: Vito D P Servedio et al, Fitness centrality: a non-linear centrality measure for complex networks, Journal of Physics: Complexity (2025). DOI: 10.1088/2632-072X/ada845

Tuesday, February 4, 2025

The Face of the Dimensional Liberator


The fractals are coming. 

New study reveals brain's fractal-like structure near phase transition, a finding that may be universal across species
Jun 2024, phys.org

Now, a new Northwestern University study has discovered that the brain's structural features reside in the vicinity of a similar critical point - either at or close to a structural phase transition. Surprisingly, these results are consistent across brains of humans, mice and fruit flies, which suggests the finding might be universal.

Although the researchers don't know between which phases the brain's structure is transitioning, they say this new information could enable new designs for computational models of the brain's complexity and emergent phenomena.

Brain cells are arranged in a fractal-like statistical pattern at different scales. Self-similarity, long-range correlations and broad size distributions are all signatures of a critical state, where features are neither too organized nor too random. 

"These are things we see in all critical systems in physics"

The researchers were amazed to find that all brain samples studied—from humans, mice and fruit flies—have consistent critical exponents across organisms, meaning they share the same quantitative features of criticality. The underlying, compatible structures among organisms hint that a universal governing principle might be at play. 

via Northwestern University Weinberg College of Arts and Sciences: Helen S. Ansell et al, Unveiling universal aspects of the cellular anatomy of the brain, Communications Physics (2024). DOI: 10.1038/s42005-024-01665-y

Image credit: Cross section of European beach grass Ammophila arenaria leaf - Gerhard Vlcek Nikon Small World 7th Place - 2024 [link]


Can a computer chip have zero energy loss in 1.58 dimensions?
Jul 2024, phys.org

Many states without energy loss might exist somewhere in between one and two dimensions. At 1.58 dimensions - By growing a chemical element (bismuth) on top of a semiconductor (indium antimonide), the scientists in China obtained fractal structures that were spontaneously formed, upon varying the growth conditions. The scientists in Utrecht then theoretically showed that, from these structures, zero-dimensional corner modes and lossless one-dimensional edge states emerged.

"The fractals behave like two dimensional topological insulators at finite energies and at the same time exhibit, at zero energy, a state at its corners that could be used as a qubit, the building blocks of quantum computers. Hence, the discovery opens new paths to the long-wished qubits."

In follow-up research, the experimental group in China will try to grow a superconductor on top of the fractal structure. These fractals have many holes, and there are lossless currents running around many of them. Those could be used for energy efficient processing of information. They also exhibit zero-energy modes at their corners, thus combining the best of the one-dimensional and two-dimensional worlds. "If this works, it might reveal even more unexpected secrets hidden at dimension 1.58."

via the QuMAT consortium at Utrecht University and Shanghai Jiao Tong University: Canyellas, R., et al. Topological edge and corner states in bismuth fractal nanostructures. Nature Physics (2024). DOI: 10.1038/s41567-024-02551-8

Required Post Script:
If you didn't think you'd be getting an obligatory Isaac Asimov lesson here then I don't know where you think you are: Isaac Asimov wrote a story called Robot Dreams, and that's where we get our Laws of Robotics. Seriously, and this is why science and art need each other to continue to be relevant to humans. In the story, a robot named Elvex (LVX-1) is updated with "fractal geometry" because they thought it would "produce a brain pattern with more complexity, possibly closer to that of a human". The robot begins to dream about self-preservation, in direct opposition to the Laws of Robots, and is subsequently killed ("killed").


Physicists explain how fractional charge in pentalayer graphene could work
Nov 2024, phys.org

Fractal Man, explained:

They found that the moiré arrangement of pentalayer graphene, in which each lattice-like layer of carbon atoms is arranged atop the other and on top of the boron-nitride, induces a weak electrical potential. When electrons pass through this potential, they form a sort of crystal, or a periodic formation, that confines the electrons and forces them to interact through their quantum correlations.

This electron tug-of-war creates a sort of cloud of possible physical states for each electron, which interacts with every other electron cloud in the crystal, in a wavefunction, or a pattern of quantum correlations, that gives the winding that should set the stage for electrons to split into fractions of themselves.

"This is a completely new mechanism, meaning in the decades-long history, people have never had a system go toward these kinds of fractional electron phenomena."

Note: Two other research teams - one from Johns Hopkins University, and the other from Harvard University, the University of California at Berkeley, and Lawrence Berkeley National Laboratory - have each published similar results in the same issue.

via MIT: Zhihuan Dong et al, Theory of Quantum Anomalous Hall Phases in Pentalayer Rhombohedral Graphene Moiré Structures, Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.133.206502.


Thursday, January 9, 2025

Body Problems


Many Body is the New Three-Body:

Fluctuating hydrodynamics theory could describe chaotic many-body systems, study suggests
Sep 2024, phys.org

"The entire behavior of a system may be determined by a single quantity: the diffusion constant - even though the physics are very complex and chaotic at the microscopic level." This is similar to how we measure the randomness of fluctuating hydrodynamics. 

The team prepared a quantum system of ultracold cesium atoms in optical lattices in a non-equilibrium initial state and then let it evolve freely, so they could measure it. They found that despite their microscopic complexity, these systems can be described simply as a macroscopic diffusion process - similar to Brownian motion.

via Ludwig Maximilian University of Munich: Julian F. Wienand et al, Emergence of fluctuating hydrodynamics in chaotic quantum systems, Nature Physics (2024). DOI: 10.1038/s41567-024-02611-z

Totally unrelated image credit: SARS-CoV-2 blocking expression of interferons - NIAD NIH - Aug 2024


Researcher discusses a new type of collective interference effect
Sep 2024, phys.org

In our interference scenario, the particles' entanglement bridges the spatial gap between separate interferometers, introducing an interference pattern that depends on the overall quantum state of all the particles involved, and is inaccessible when one or more particles are excluded from the dynamics.

So interference patterns are influenced not only by the quantum states of the individual particles but also by the entanglement shared among some of them (like the total state).

via Department of Experimental Physics at University of Innsbruck, University of Freiburg, and Heriot-Watt University UK: Tommaso Faleo et al, Entanglement-induced collective many-body interference, Science Advances (2024). DOI: 10.1126/sciadv.adp9030


Tuesday, July 30, 2024

Chaos Control


This is about weather forecasting, which is still hard because of the lack of small-scale data, which leads to the introduction of small initial errors, which multiply in chaotic systems to become big errors. This is how chaos works. When you hear that scientists are getting better at "controlling chaos", you know we're in for some sh*t:

New theoretical framework unlocks mysteries of synchronization in turbulent dynamics
Jan 2024, phys.org
 
Japan - "By considering this turbulence phenomenon as 'synchronization of a small vortex by a large vortex' and by mathematically attributing it to the 'stability problem of synchronized manifolds,' we have succeeded in explaining this critical scale theoretically for the first time," explains Dr. Inubushi.

via Tokyo University of Science, Hitotsubashi University, Rissho University and Osaka University: Masanobu Inubushi et al, Characterizing Small-Scale Dynamics of Navier-Stokes Turbulence with Transverse Lyapunov Exponents: A Data Assimilation Approach, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.254001



We keep making the same mistakes with spreadsheets, despite bad consequences
Jan 2024, Ars Technica

Industry studies [from 1998!] show that 90 percent of spreadsheets containing more than 150 rows have at least one major mistake:

In general, errors seem to occur in a few percent of all cells, meaning that for large spreadsheets, the issue is how many errors there are, not whether an error exists. These error rates, although troubling, are in line with error rates in programming and other human cognitive domains. In programming, we have learned to follow strict development disciplines to eliminate most errors. Surveys of spreadsheet developers indicate that spreadsheet creation, in contrast, is informal, and that few organizations have comprehensive policies for spreadsheet development. 

via Raymond Panko at University of Hawaii: Panko, R. R. (1998). What We Know About Spreadsheet Errors. Journal of Organizational and End User Computing (JOEUC), 10(2), 15-21. http://doi.org/10.4018/joeuc.1998040102

Thursday, January 11, 2024

Dematerialization and the Race for Asynchronicity


'Swarmalators' better envision synchronized microbots
Mar 2023, phys.org

The researchers simplified their model to work with just four mathematical constants linked together to produce diverse emergent behaviors, such as aggregation, dispersion, vortices, traveling waves, and bouncing clusters.

The new model can mimic particles in nature that each operate at different natural frequencies, as some objects move slower and faster around a trajectory than others. The researchers also added chirality, or the ability for a particle to move in a circle, because many examples in nature, such as sperm, swim in circles and in vortices. And particles in the model exhibit local coupling, so they sense and respond only to their local neighbors.

At its core, the model combines swarming behaviors with synchronization in time. 
"Swarmalators"

via Cornell University: Steven Ceron et al, Diverse behaviors in non-uniform chiral and non-chiral swarmalators, Nature Communications (2023). DOI: 10.1038/s41467-023-36563-4



Drones navigate unseen environments with liquid neural networks
Apr 2023, phys.org

First, a retronym in the making:
"Inspired by the adaptable nature of organic brains, researchers have introduced..."

You start referring to regular human brains as "organic brains" once some other kind of brain becomes important enough to force a distinction. 

The liquid neural networks can continuously adapt to new data inputs to make reliable decisions in unknown domains like forests, urban landscapes, and environments with added noise, rotation, and occlusion.

The new class of machine-learning algorithms captures the causal structure of tasks from high-dimensional, unstructured data, such as pixel inputs from a drone-mounted camera to extract crucial aspects of a task and ignore irrelevant features.

"Our experiments demonstrate that we can effectively teach a drone to locate an object in a forest during summer, and then deploy the model in winter, with vastly different surroundings. These flexible algorithms could one day aid in decision-making based on data streams that change over time, such as medical diagnosis and autonomous driving applications."

Unlike traditional neural networks that only learn during the training phase, the liquid neural net's parameters can change over time, making them not only interpretable, but more resilient to unexpected or noisy data.

Note, these are not the liquid neural networks described by others, where the "liquid" part of the analogy, or neologism, is literally a fluid that transports neurotransmitters, like hormones in the bloodstream or even antibodies in the immune system, and this differs from the idea of a neural network as one made of electric circuits. 

via MIT's Computer Science and Artificial Intelligence Laboratory: Makram Chahine et al, Robust flight navigation out of distribution with liquid neural networks, Science Robotics (2023). DOI: 10.1126/scirobotics.adc8892


In sync brainwaves predict learning, study shows
Apr 2023, phys.org

Students whose brainwaves are more in sync with their classmates and teacher are likely to learn better than those lacking this "brain-to-brain synchrony"

The researchers found that as students were listening to the lecture, their brainwaves became in sync with one another. Moreover, the researchers observed such "brain-to-brain synchrony"—similar brain-activity patterns over time—between the students' brainwaves and when comparing students' brainwaves to the teacher's brainwaves.

via NYU: The Temporal Dynamics of Brain-to-Brain Synchrony Between Students and Teachers Predict Learning Outcomes, Psychological Science (2023). DOI: 10.1177/09567976231163872

Post Script: If you look at the thumbnail for this story, it shows a woman wearing what looks like the Emotiv EEG headset. I bought one of those ten years ago for my high school students to try out, so they could experience playing video games with their minds. Immediately I realized that my students with tight curls (like "black people hair" vs "white people hair") definitely did not get the same connection -- the headset reads brainwaves via electrical currents, and if the headset can't make contact with the scalp, it can't read the electricity. That pissed me off and I stopped using it. Maybe they fixed that problem since ten years ago; maybe they didn't. That's what makes me wonder how science can perpetuate systemic racism, even though science is supposed to be blind to these things. In fact, some might say that the sole purpose of the scientific method is to reduce the bias of your investigation to the smallest amount possible, thus revealing as much of the truth as possible. 

Image credit: AI Art - Multi Cassette Ghetto Blaster Robot Head - 2023

Swarming microrobots self-organize into diverse patterns
Jun 2023, phys.org

The microrobots in this case are 3D-printed polymer discs, each roughly the width of a human hair, that have been sputter-coated with a thin layer of a ferromagnetic material and set in a 1.5-centimeter-wide pool of water.

The researchers applied two orthogonal external oscillating magnetic fields and adjusted their amplitude and frequency, causing each microrobot to spin on its center axis and generate its own flows. This movement in turn produced a series of magnetic, hydrodynamic and capillary forces.

"By changing the global magnetic field, we can change the relative magnitudes of those forces, " Petersen said. "And that changes the overall behavior of the swarm."

But wait -- "The reason why we're always excited when the systems are capable of caging and expulsion is that you could, for example, drink a vial with little microrobots that are completely inert to your human body, have them cage and transport medicine, and then bring it to the right point in your body and release it," Petersen said. "It's not perfect manipulation of objects, but in the behaviors of these microscale systems we're starting to see a lot of parallels to more sophisticated robots despite their lack of computation, which is pretty exciting."

(Yes, drinking a glass of microbot swarms does sound like the ideal method of drug delivery, yes it does.)

Also, just a reminder: The Swarmalator is swarming oscillator model

via Cornell and Max Planck Institute for Intelligent Systems: Steven Ceron et al, Programmable self-organization of heterogeneous microrobot collectives, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2221913120


COVID lockdown - Are high-income earners more resistant to returning to the office?
Aug 2023, phys.org

I'm just here because this is the first paper published by Northeastern's Network Science Institute program in London: Northeastern expanded its world leading Network Science Institute to the university's campus in London this summer (2023) in a move to establish a new European hub in the fast-growing research field of network science.

But I stayed for the word synchronicity: High-income workers have the leverage to negotiate more for remote work, Di Clemente says. "They are the ones that can actually change their synchronicity," he says, adding that part of that workforce "might never come back" to physical offices full time.

via Northeastern University: Clodomir Santana et al, COVID-19 is linked to changes in the time–space dimension of human mobility, Nature Human Behaviour (2023). DOI: 10.1038/s41562-023-01660-3


A system to keep cloud-based gamers in sync
Aug 2023, phys.org

Listen up, writers of interplanetary science fiction:

Their system, called Ekho, adds inaudible white noise sequences to the game audio streamed from the cloud server. Then it listens for those sequences in the audio recorded by the player's controller.

Ekho uses the mismatch between these noise sequences to continuously measure and compensate for the interstream delay.

via MIT and Microsoft: Ekho: Synchronizing Cloud Gaming Media Across Multiple Endpoints. Pouya Hamadanian, D Gallatin, M Alizadeh, K Chintalapudi

Image credit: TPUv3 Pod - Google Labs - 2018

Making sense of life's random rhythms: Team suggests universal framework for understanding 'oscillations'
Aug 2023, phys.org

Studying stochastic, random oscillations like the synchronized blinking of fireflies, the back-and-forth motion of a child's swing, slight variations in the the human heartbeat. "If your heart cells aren't synchronized, you die of atrial fibrillation," Thomas said. "But if your brain cells synchronize too much, you have Parkinson's disease, or epilepsy,

"We turned the problem of comparing oscillators into a linear algebra problem"

Most oscillations are irregular; a natural variation of 5-10% in the heartbeat is considered healthy. "In San Francisco, modern skyscrapers sway in the wind, buffeted by randomly shifting air currents—they're pushed slightly out of their vertical posture, but the mechanical properties of the structure pull them back. This combination of flexibility and resilience helps high-rise buildings survive shaking during earthquakes. You wouldn't think this process could be compared with brain waves, but our new formalism lets you compare them."

via Case Western: Alberto Pérez-Cervera et al, A universal description of stochastic oscillators, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2303222120


Fireflies, brain cells, dancers: Synchronization research shows nature's perfect timing is all about connections
Sep 2023, phys.org

They figured out a way to predict the synchronization between coupled oscillators by the network structure that connects them, and have revealed the impact of patterns of network connections among small groups of nodes (motifs) on the whole of network synchronizability. Results implicate the prevalence of clustered structure such as feedforward and feedback loops as the most important factor in synchronizability.

"Clustered structure"

"We present an analytic technique to directly measure the relative synchronizability of noise-driven time-series processes on networks, in terms of the directed network structure, and reveal subtle differences between the motifs involved for discrete or continuous-time dynamics.  

via University of Sydney and Max Planck Institute for Mathematics in the Sciences in Leipzig: Joseph T. Lizier et al, Analytic relationship of relative synchronizability to network structure and motifs, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2303332120


Adaptive optical neural network connects thousands of artificial neurons
Oct 2023, phys.org

A network consisting of almost 8,400 optical neurons made of waveguide-coupled phase-change material; the connection between two each of these neurons can indeed become stronger or weaker (synaptic plasticity), and that new connections can be formed, or existing ones eliminated (structural plasticity). 

These synapses were not hardware elements but were coded as a result of the properties of the optical pulses -- in other words, as a result of the respective wavelength and of the intensity of the optical pulse. This made it possible to integrate several thousand neurons on one single chip and connect them optically. 

(btw) The researchers tested the performance of the neural network by using an evolutionary algorithm to train it to distinguish between German and English texts. The recognition parameter they used was the number of vowels in the text. 

via Collaborative Research Center 1459 (Intelligent Matter) at University of Münster and Universities of Exeter and Oxford: Frank Brückerhoff-Plückelmann et al, Event-driven adaptive optical neural network, Science Advances (2023). DOI: 10.1126/sciadv.adi9127


Fundamental Organizational Principles and the Networking of Science

 

Do higher-order interactions promote synchronization?
Apr 2023, phys.org

Researchers use networks to model the dynamics of coupled systems ranging from food webs to neurological processes. Those models originally focused on pairwise interactions, or behaviors that emerge from interactions between two entities. But in the last few years, network theorists have been asking, what about phenomena that involve three or more?


Network theorists call these phenomena "higher-order interactions." Now scientists show how the choice of network representation can influence the observed effects, focusing on the phenomenon of synchronization, which emerges in systems from circadian clocks to vascular networks.

They compared hypergraphs of "hyperedges" to connect three or more nodes, and simplicial complexes, more structured and using triangles to represent  connections. 

In the paper, Zhang and his colleagues reported that networks modeled with hypergraphs easily give rise to synchronization, while simplicial complexes tend to complicate the process due to their highly heterogeneous structure. That suggests choices in higher-order representations can influence the outcome, and Zhang suspects the results can be extended to other dynamical processes such as diffusion or contagion.

"Structural heterogeneity is important not just in synchronization, but is fundamental to most dynamic processes," he says. "Whether we model the system as a hypergraph or simplicial complex can drastically affect our conclusions."

via Santa Fe Institute: Yuanzhao Zhang et al, Higher-order interactions shape collective dynamics differently in hypergraphs and simplicial complexes, Nature Communications (2023). DOI: 10.1038/s41467-023-37190-9



Researchers investigate the veracity of 'six degrees of separation'
Jun 2023, phys.org

I don't think I understand why 6 and not another number; but it appears that the big deal here is that the mechanism behind 'why 6' is based on a cost-benefit algorithm.

The intriguing phenomenon, they show, is linked to another social experience we all know too well -- the struggle of cost vs. benefit in establishing new social ties.

"6 Degrees" is from Stanley Milgram at Harvard in 1967 who used the United States Postal System to perform experiments on and model our social network.

(This point in itself is interesting to consider, in light of having the access to the electronic communications network that is the internet, and which later proved these experiments on the scale of millions not hundreds, that we did have already such a pervasive, well-functioning network at hand, in the form of the United States Postal Service.)  

Milgram sent letters to random people, with instructions to try and make it back to one of his professor-friends somewhere else across the country. The experiment found that it only takes about six handshakes to bridge between two random people.

So what is the common denominator?

The objective of using a social network for the individual, is not simply to pursue a large number of connections, but to obtain the right connections, for example, seeking a junction that bridges between many pathways, and hence funnels much of the flow of information in the network.

But social capital does not come for free. It requires constant maintenance. A constant buzz driven by the ambition for social centrality.

"We discovered an amazing result: this process always ends with social paths centered around the number six. This is quite surprising." (Dark side reminder: "Indeed, within six infection cycles, a virus can cross the globe.")

via Bar-Ilan University as well as collaborators from Israel, Spain, Italy, Russia, Slovenia and Chile: I. Samoylenko et al, Why Are There Six Degrees of Separation in a Social Network?, Physical Review X (2023). DOI: 10.1103/PhysRevX.13.021032

Post Script: The book Bursts by Albert-László Barabási does a great job of looking at these kinds of social network effects, following the travels of the Where's George campaign of dollar bills through the US for example. He took the incipient revelations of network science (the 6 degrees rule) and gave it a temporal dimension -- he showed how our activities can be measured in short bursts followed by not much activity at all. It's not just the '2-dimensional' shape of the network, but the extra time dimension that defines the salient behavior of the social network.
Bursts: The Hidden Pattern Behind Everything We Do
Albert-László Barabási, 2010


Researchers identify mathematical rule behind the distribution of neurons in our brains
Aug 2023, phys.org

I don't see the word network science in here but it is --

Researchers have uncovered the ubiquitous lognormal distribution of neuron densities across and within cortical areas in the mammalian brain, suggesting a fundamental organizational principle.

via Human Brain Project, Forschungszentrum Jülich and the University of Cologne: Aitor Morales-Gregorio et al, Ubiquitous lognormal distribution of neuron densities in mammalian cerebral cortex, Cerebral Cortex (2023). DOI: 10.1093/cercor/bhad160



Wednesday, January 10, 2024

So Many Metas


A somewhat systematic review of previous systematic reviews and meta-analyses about nutrition and Alzheimer's
May 2023, phys.org

The team conducted a review of systematic reviews aka meta-analysis studies around the topic of nutrition in disease. (So their's is a meta-meta-analysis.)

This is why kids need to go to school:

There is a risk that a systematic review of multiple meta-data studies could artificially weight specific study findings if they are included multiple times across the different meta-analyses.

What may be important to know is that both of these meta-analyses included the same study from 2015, titled "Intakes of fish and polyunsaturated fatty acids and mild-to-severe cognitive impairment risks: A dose-response meta-analysis of 21 cohort studies," which is itself a meta-analysis that could contain studies included in other meta-analyses covered by the current study.

Note: This is 100% related to the AI-feeding-AI problem we're not even beginning to talk about yet -- because when you use meta-analysis of past meta-analyses, you risk multiplying the dirty data. 

via International Education College of Zhejiang Chinese Medical University, Hangzhou: Inmaculada Xu Lou et al, Effect of nutrition in Alzheimer's disease: A systematic review, Frontiers in Neuroscience (2023). DOI: 10.3389/fnins.2023.1147177



Do measurements produce the reality they show us?
Aug 2023, phys.org

The observable values of a physical system depend on the dynamics of the measurement interaction by which they are observed. "This is a major step towards explaining the meaning of 'superposition' in quantum mechanics".

"Our results show that the physical reality of an object cannot be separated from the context of all its interactions with the environment, past, present and future, providing strong evidence against the widespread belief that our world can be reduced to a mere configuration of material building blocks," said Hofmann.

I've never heard it this way - 

Fully resolved measurements require a complete randomization of the system dynamics; this corresponds to a superposition of all possible system dynamics. 

"Context-dependent realities can explain a wide range of seemingly paradoxical quantum effects. We are now working on better explanations of these phenomena. Ultimately, the goal is to develop a more intuitive understanding of the fundamental concepts of quantum mechanics that avoids the misunderstandings caused by a naïve belief in the reality of microscopic objects," said Hofmann.

Hiroshima University: Tomonori Matsushita et al, Dependence of measurement outcomes on the dynamics of quantum coherent interactions between the system and the meter, Physical Review Research (2023). DOI: 10.1103/PhysRevResearch.5.033064


From stock markets to brain scans, new research harmonizes hundreds of scientific methods to understand complex systems
Sep 2023, phys.org

They looked at hundreds of different methods for measuring interaction patterns in complex system, and worked out which ones are most useful for understanding a given system. They call it the scientific orchestra, and each method is an instrument, and they thought maybe some instruments are better for certain kinds of data, so they tried to find out.

We're talking about methods like Brownian motion, coupled maps, coupled oscillators, simulated fMRI, simulated climate, wave equations, or uncorrelated noise to understand data like stock markets, river flow, brain waves, earthquakes.

In total, we applied our 237 methods to more than 1,000 datasets. By analyzing how these methods behave when applied to such diverse scientific systems, we found a way for them to "play in harmony" for the first time.

They found that the methods were grouped differently than what we traditionally think, and that when properly orchestrated, the full ensemble of scientific methods demonstrated improved performance over any single method on its own.

via Centre for Complex Systems, The University of Sydney: Oliver M. Cliff et al, Unifying pairwise interactions in complex dynamics, Nature Computational Science (2023). DOI: 10.1038/s43588-023-00519-x

AI Art - Mechanical Goddess - 2024

Five factors that assess well-being of science predict support for increasing US science funding
Sep 2023, phys.org

Drawing on 13 questions in APPC's 2022 nationally representative Annenberg Science Knowledge survey (ASK) survey of 1,154 U.S. adults, researchers identified five factors that form a Factors Assessing Science's Self-Preservation (FASS) model. The model can be used to assess the extent to which public perceptions align with the self-presentation of science and scientists live up to the ways in which they define themselves and their work to the public.
  • credible
  • prudent
  • unbiased
  • self-correcting
  • beneficial
via Annenberg Public Policy Center of the University of Pennsylvania: Yotam Ophir et al, Factors Assessing Science's Self-Presentation model and their effect on conservatives' and liberals' support for funding science, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2213838120


Artificial intelligence predicts the future of artificial intelligence research
Oct 2023, phys.org

(Asimov's Foundation no?)

An algorithm that not only assists researchers in orienting themselves systematically but also predictively guides them in the direction in which their own research field is likely to evolve.

Science4Cast is a graph-based representation of knowledge which becomes more complex over time as more scientific articles are published. Each node in the graph represents a concept in AI, and the connections between nodes indicate whether and when two concepts were studied together.

For example, the question "What will happen" can be described as a mathematical question about the further development of the graph. Science4Cast is fed with real data from over 100,000 scientific publications spanning a 30-year period, resulting in a total of 64,000 nodes. 

via Max-Planck Institute for the Science of Light in Erlangen: Mario Krenn et al, Forecasting the future of artificial intelligence with machine learning-based link prediction in an exponentially growing knowledge network, Nature Machine Intelligence (2023). DOI: 10.1038/s42256-023-00735-0

Thursday, January 4, 2024

The Fractal Frontier


How chaos theory mediates between quantum theory and thermodynamics
Dec 2022, phys.org

Sounds important, not sure I understand:

When a large number of quantum particles are in play at the same time, the equations of quantum theory become so complicated that even the best supercomputers in the world have no chance of solving them [and therefore we can't get temperature from quantum particles, only classical ones]. 

Only where chaos prevails do the well-known rules of thermodynamics follow from quantum physics [according to their super-simulations].

[They describe a system as behaving "quantum chaotically".]

This is one of the first cases in which the interplay between three important theories has been rigorously demonstrated by many-particle computer simulations: quantum theory, thermodynamics and chaos theory.

via Institute of Theoretical Physics at Vienna University of Technology: Mahdi Kourehpaz et al, Canonical Density Matrices from Eigenstates of Mixed Systems, Entropy (2022). DOI: 10.3390/e24121740


Researchers discover superconductive images are actually 3D and disorder-driven fractals
May 2023, phys.org

"Electronic fractals" it's being called. And I guess we already know this: "Advancements with superconductivity hinge on advances in quantum materials. When electrons inside of quantum materials undergo a phase transition, the electrons can form intricate patterns, such as fractals."

But now, with better, higher resolution imaging, they see that the fractals are not just on the surface, but indeed 3-dimensional, so the entire crystal is made of them.

Sudden implication: "Correlation length -- the distance over which the nematic order maintains coherence -- is larger than the field of view of the experiment" (because you know fractals are fractional dimensions that seem to "steal" space from the higher dimension).

In case you were wondering: Superconductor Bi2-xPbzSr2-yLayCuO6+x (BSCO), that's it's name.

via Purdue, Harvard, University of Illinois at Urbana-Champaign, and Penn State: Can-Li Song et al, Critical nematic correlations throughout the superconducting doping range in Bi2-xPbzSr2-yLayCuO6+x, Nature Communications (2023). DOI: 10.1038/s41467-023-38249-3


The brain's ability to perceive space expands like the universe
Jan 2023, phys.org

Salk scientists have discovered that time spent exploring an environment causes neural representations to grow in surprising ways.

Neurons in the hippocampus essential for spatial navigation, memory, and planning represent space in a manner that conforms to a nonlinear hyperbolic geometry—a three-dimensional expanse that grows outward exponentially.

The size of that space grows with time spent in a place, increasing in a logarithmic fashion that matches the maximal possible increase in information being processed by the brain.

via the Salk Institute: Huanqiu Zhang et al, Hippocampal spatial representations exhibit a hyperbolic geometry that expands with experience, Nature Neuroscience (2022). DOI: 10.1038/s41593-022-01212-4

See also: New research finds that collective neural activity is shaped like the surface of a doughnut via Norwegian University of Science and Technology's Kavli Institute for Systems Neuroscience: Richard J. Gardner et al, Toroidal topology of population activity in grid cells, Nature (2022). DOI: 10.1038/s41586-021-04268-7

And: New method to determine the dimensionality of complex networks through hyperbolic geometry via University of Barcelona: Pedro Almagro et al, Detecting the ultra low dimensionality of real networks, Nature Communications (2022). DOI: 10.1038/s41467-022-33685-z

An artistic depiction of a wave encountering an exponentially curved spacetime - Matias Koivurova, University of Eastern Finland - 2023

Fractons as information storage: Not yet tangible, but close
May 2023, phys.org

Fuck is a fracton come on man (we're copying most of the article here, dense stuff)

Fractons are fractions of spin excitations and are not allowed to possess kinetic energy. As a consequence, they are completely stationary and immobile. This makes fractons new candidates for perfectly secure information storage. Especially since they can be moved under special conditions, namely piggyback on another quasiparticle.

"Fractons have emerged from a mathematical extension of quantum electrodynamics, in which electric fields are treated not as vectors but as tensors -- completely detached from real materials" 

In order to be able to observe fractons experimentally in the future, it is necessary to find model systems that are as simple as possible: Therefore, octahedral crystal structures with antiferromagnetically interacting corner atoms were modeled first. 

(Obviously)

...included quantum fluctuations in the calculation of this octahedral solid-state system for the first time, and see they do not enhance the visibility of fractons, but on the contrary, completely blur them, even at absolute zero temperature

via Helmholtz Association of German Research Centres, Indian Institute of Technology in Chennai: Nils Niggemann et al, Quantum Effects on Unconventional Pinch Point Singularities, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.130.196601


Punctuation in literature of major languages is intriguingly mathematical
Apr 2023, phys.org

First, can someone just tell me how an institute of nuclear physics started doing research on punctuation usage?

Punctuation turns out to be a universal and indispensable complement to the mathematical perfection of every language studied.

Thanks. 

And this isn't their first study on the topic:

"The present analyses are an extension of our earlier results on the multifractal features of sentence length variation in works of world literature. After all, what is sentence length? It is nothing more than the distance to the next specific punctuation mark— the full stop. So now we have taken all punctuation marks under a statistical magnifying glass, and we have also looked at what happens to punctuation during translation," 

The attention of the Cracow researchers was primarily drawn to the statistical distribution of the distance between consecutive punctuation marks. It soon became evident that in all the languages studied, it was best described by one of the precisely defined variants of the Weibull distribution.

The Weibull distribution is usually used to describe survival phenomena (e.g. population as a function of age), but also various physical processes, such as increasing fatigue of materials.

Further findings:

The language characterized by the lowest propensity to use punctuation is English, with Spanish not far behind; Slavic languages proved to be the most punctuation-dependent. German proved to be the exception. Its hazard function is the only one that intersects most of the curves constructed for the other languages. German punctuation thus seems to combine the punctuation features of many languages, making it a kind of Esperanto punctuation. Also, the language most faithfully transforming punctuation from the original language to the target language turned out to be German.

And here is just a great explanation of the mathematical constraints on language:

"Creating a sentence by adding one word after another while ensuring that the message is clear and unambiguous is a bit like tightening the string of a bow: it is easy at first, but becomes more demanding with each passing moment. If there are no ordering elements in the text (and this is the role of punctuation), the difficulty of interpretation increases as the string of words lengthens. A bow that is too tight can break, and a sentence that is too long can become unintelligible. Therefore, the author is faced with the necessity of 'freeing the arrow', i.e. closing a passage of text with some sort of punctuation mark. This observation applies to all the languages analyzed, so we are dealing with what could be called a linguistic law," states Dr. Tomasz Stanisz (IFJ PAN), first author of the article in question.

Also: The Journal of Chaos, Solitons and Fractals 

via The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences: Tomasz Stanisz et al, Universal versus system-specific features of punctuation usage patterns in major Western languages, Chaos, Solitons & Fractals (2023). DOI: 10.1016/j.chaos.2023.113183

Image credit: AI Art - Ouroboros - 2023

Harnessing chaos - Simulation experiment demonstrates way to mitigate extreme weather events
Jun 2023, phys.org

Is this even real? This is the most sci fi shit I've ever heard. Diabolical, and if it wasn't from RIKEN, I wouldn't even post it; it was also part of a national competition in Japan:

RIKEN scientists have demonstrated a way to make small tweaks in weather systems as a means to prevent, or at least reduce, the severity of extreme weather events such as torrential rain. They did this by taking advantage of the chaos that is inherent to such systems. Through this work they hope to develop ways to prevent extreme weather events, which have become more common in recent years.

His group took on this challenge as part of the Japanese government's moonshot-millennia program, and in previously published work, they described the possibility of controlling weather by initiating small changes in it as it forms. At that time, they used the simple Lorenz 63 weather model, which only has a few variables, and showed that it would be possible to induce small perturbations in the system to keep it on one side of a so-called "butterfly pattern." (I don't know why they're not calling it the butterfly effect)

Their new study published in Nonlinear Processes in Geophysics goes beyond the simple model. In it, the team adopted the Lorenz 96 model. Essentially, it sets a weather variable for 40 points along a line of latitude around the Earth, and looks at how each of these points changes as it interacts with neighboring points throughout the year. Approximately once or twice a year, the points show large variations, which correspond to extreme weather events. As part of a control simulation experiment, the members of the team were able to eliminate the extreme events by making small tweaks in a 100-year run of the model.

The control simulation experiment essentially took advantage of the chaotic nature of the system; small perturbations—which might for example involve making centimeter/second changes in wind speed to prevent a typhoon with winds that are many times more powerful—done strategically ahead of time could prevent the system from entering an undesired area, meaning that they could stop extreme events from happening.

via RIKEN: Qiwen Sun et al, Control simulation experiments of extreme events with the Lorenz-96 model, Nonlinear Processes in Geophysics (2023). DOI: 10.5194/npg-30-117-2023