# gst: apropos of uncertainty, notes on uncertainty, information, and classical dynamics.

<< Survival in this world is an adventure because we are so ignorant and everything around us seems so uncertain. In fact, it is hard to think of any realistic phenomenon that is completely free from one of the three kinds of uncertainty—deterministic (chaotic), stochastic, and quantum; more often than not, all of the three are present in various degrees. Thus, in order to gain any knowledge about any realistic system, one must understand how to characterize, quantify, and interpret these uncertainties. >>️

Sagar Chakraborty. Eclectic Notes on Uncertainty, Information, and Classical Dynamics. arXiv: 2404.13511v1 [physics.class-ph]. Apr 21, 2024.

https://arxiv.org/abs/2404.13511

Also: uncertainty, noise, error, in  https://www.inkgmr.net/kwrds.html 

Keywords: gst, information, uncertainty, ambiguity, noise, error 

# gst: taming uncertainty, a tutorial by NaN et Al.

<< All models are wrong, but some are useful. >>. George Box. ️

Nan Chen, Stephen Wiggins, Marios Andreou. Taming Uncertainty in a Complex World: The Rise of Uncertainty Quantification - A Tutorial for Beginners. arXiv: 2408.01823v1 [math.DS]. Aug 3, 2024. 

https://arxiv.org/abs/2408.01823

Also: NaN 'Not a Number'. In: Onda pneica. Apr 10, 2005 (quasi-stochastic poetry) https://inkpi.blogspot.com/2005/04/1694b-onda-pneica.html ;  nan(). In: Linux manual. https://www.man7.org/linux/man-pages/man3/nanf.3.html

Also: << Amico, qualunque  cosa suonerai . . . >>. Jelly Roll Morton. In: Soniche a ramulo. Jan 28, 2007 (quasi-stochastic poetry). https://inkpi.blogspot.com/2007/01/2113-soniche-ramulo.html  

Also: uncertainty, Mr. Jelly Roll Morton, jazz, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, uncertainty, Jelly Roll, jazz

# gst: approaching uncertainty among many-body real-time dynamics

<< Analog quantum simulation is emerging as a powerful tool for uncovering classically unreachable physics such as many-body real-time dynamics. >>️

AA << examines the interplay of errors arising from simulation of approximate time evolution with those due to practical, real-world device constraints. >>️

Nikita A. Zemlevskiy, Henry F. Froland, Stephan Caspar. Optimization of algorithmic errors in analog quantum simulations. Phys. Rev. A 109, 052425. May 15, 2024. 

https://journals.aps.org/pra/abstract/10.1103/PhysRevA.109.052425

<< The new technique focuses on two sources of error that arise from the approximations used to map the quantum system of interest to the analog quantum simulator. In a real-world simulator, these error sources are linked in a complex way, and individually minimizing each error can increase the overall uncertainty of a simulation. (AA) tackled this problem by first isolating the two error sources and then carefully studying their interplay. This analysis enabled the researchers to finely tune a simulation’s parameters to minimize its overall uncertainty and to maximize its precision. >>️

Ryan Wilkinson. Quantifying Uncertainties in Quantum Simulations. 

Physics 17, s51. May 15, 2024. 

https://physics.aps.org/articles/v17/s51

Also: uncertainty, error, noise in https://www.inkgmr.net/kwrds.html 

Keywords: gst, uncertainty, error, noise

# gst: the physics of squeezing; how to squeeze out (quantum) noise

<< 'Squeezing' is used in physics, among other things, to improve the resolution of measuring instruments. It allows disturbing noise to be suppressed in a way that smaller signals can be detected more sensitively. (..) (AA) has now been able to show how such a squeezed state can be measured in a much simpler way than with the existing methods. Moreover, the new method allows examining squeezed states in systems where such measurements were not possible before. >> [1]

<< In the experiment (..) the thermal fluctuations of a vibrating nanomechanical string resonator are squeezed. The nanostring can be thought of as a tiny guitar string, a thousand times thinner and shorter than a human hair. (..)  If the string is deflected far enough, it ceases to behave linearly. This means that the force that deflects the string is no longer proportional to the force that pulls it back to its original position. The strong drive alters the thermal fluctuations as a result of a violation of the time reversal symmetry. In phase space, they no longer look like a circle but like an ellipse: At least in one direction, its diameter, i.e. the noise, becomes significantly smaller—it is squeezed. >> [1]

<< Quantum squeezing was a theory that was first proposed in the 1980s, the general idea being that quantum vacuum noise can be represented as a sphere of uncertainty along two main axes: phase and amplitude. If this sphere were squeezed, like a stress ball, in a way that constricted the sphere along the amplitude axis, this would in effect shrink the uncertainty in the amplitude state of a vacuum (the squeezed part of the stress ball), while increasing the uncertainty in the phase state (stress ball's displaced, distended portion). Since it is predominantly the phase uncertainty that contributes noise to LIGO, shrinking it could make the detector more sensitive to astrophysical signals. (..) The heart of the squeezer is an optical parametric oscillator, or OPO — a bowtie-shaped device that holds a small crystal within a configuration of mirrors. When the researchers direct a laser beam to the crystal, the crystal's atoms facilitate interactions between the laser and the quantum vacuum in a way that rearranges their properties of phase versus amplitude, creating a new, "squeezed" vacuum that then continues down each of the detector's arm as it normally would. This squeezed vacuum has smaller phase fluctuations than an ordinary vacuum, allowing scientists to better detect gravitational waves. >> [2]

[1] - Measure squeezing in a novel way. University of Konstanz. Jun 25, 2020.   https://phys.org/news/2020-06-measure-squeezing-in-a-novel.html ; 

J. S. Huber, G. Rastelli, et al. Spectral Evidence of Squeezing of a Weakly Damped Driven Nanomechanical Mode.  Phys. Rev. X 10, 021066 – Jun 23,  2020.   https://journals.aps.org/prx/abstract/10.1103/PhysRevX.10.021066 

[2] - Jennifer Chu. New instrument extends LIGO’s reach. Technology "squeezes" out quantum noise so more gravitational wave signals can be detected. MIT. Dec 5, 2019.   https://news.mit.edu/2019/ligo-reach-quantum-noise-wave-1205

# behav: unfrequent events under radical uncertainty; rats tend to avoid black swan situations.

AA << present a novel experimental design that aims at measuring the extent to which animal subjects are sensitive to rare and extreme events and, in addition, how rats respond to those very unfrequent events under radical uncertainty. (..) the novelty of (AA) design is that it provides two direct measures that help interpreting (..) behavioral data: Total Sensitivity to Rare and Extreme Events, and One-sided Sensitivity to Rare and Extreme Events with Black-Swan Avoidance/Jackpot-Seeking behaviors as limiting cases. >>️

<< First, most rats (..) can be grouped into a moderate to high Total Sensitivity group. This means that most rats diversify their choices across options in such a way that they more often rely on convex ones than on concave ones overall. Therefore, they tend to seek extreme gains/Jackpots and to avoid extreme losses/ Black Swans. In addition, most rats (..) tend to exhibit Black Swan Avoidance, which indicates that, given Total Sensitivity, they tend to try more often to avoid Black Swans than to seek Jackpots. (AA) interpret such a behavior as significant aversion towards uncertainty about rare and extreme losses.  >>️

<< all rats diversify their choices across a set of options, which is reminiscent of observed behaviors such as, for example, bet-hedging in animals and financial portfolio strategies used by humans >>

️

<< results from similar experiments among different species might be of interest for the analysis of neurobiological substrates involved in decision-making and its evolutionary traits in the context of rare and extreme events. >>️

Mickael Degoulet, Louis-Matis Willem, et al. Decision-Making in Rats is Sensitive to Rare and Extreme Events: the Black Swan Avoidance. bioRxiv 10.1101/2021.11.01.466806v1. Nov 04, 2021. 

https://www.biorxiv.org/content/10.1101/2021.11.01.466806v1

 Keywords: behav, game, decision-making, bet-hedging, trading, uncertainty, gain, loss, black swan 

# gst: small-scale random perturbations, Arnold's cat spontaneously stochastic

<< Multi-scale systems (..) may possess a fascinating property of spontaneous stochasticity: a small-scale initial uncertainty develops into a randomly chosen largescale state in a finite time, and this behavior is not sensitive to the nature and magnitude of uncertainty (..). >>

A << intriguing form is the Eulerian spontaneous stochasticity (ESS) of the velocity field itself: an infinitesimal small-scale noise triggers stochastic evolution of velocity field at finite scales and times. >>

AA << prove that a formally deterministic system with scaling symmetry yields a stochastic process with Markovian properties if it is regularized with a vanishing small-scale random perturbation. Besides its significance for understanding turbulence, (their) model extends the phenomenon of ESS beyond the scope of fluid dynamics: (AA) discuss a prototype of a feasible experiment for observing ESS in optics or electronics, as well as potential applications in other physical systems.>>

Alexei A. Mailybaev, Artem Raibekas. Spontaneously stochastic Arnold's cat. arXiv:2111.03666v1 [nlin.CD]. Nov 5,  2021.

https://arxiv.org/abs/2111.03666

keywords: gst, Arnold's cat, randomness, stochasticity, spontaneous stochasticity, small-scale random perturbations, noise, turbulence, chaos 

# acad: oops! the scientific world is abuzz ... scientists first and foremost should "embrace uncertainty" and "be thoughtful, open and modest." ...

<< The scientific world is abuzz following recommendations by two of the most prestigious scholarly journals – The American Statistician and Nature – that the term "statistical significance" be retired. In their introduction to the special issue of The American Statistician on the topic, the journal’s editors urge "moving to a world beyond 'p<0.05,'" the famous 5 percent threshold for determining whether a study’s result is statistically significant.  (..) scientists first and foremost should "embrace uncertainty" and "be thoughtful, open and modest." >>

Valen E. Johnson.  Is it the end of 'statistical significance'? The battle to make science more uncertain. Texas A&M University. April 1, 2019.
 
http://theconversation.com/is-it-the-end-of-statistical-significance-the-battle-to-make-science-more-uncertain-114161  

Ronald L. Wasserstein, Allen L. Schirm,   Nicole A. Lazar. Moving to a World Beyond "p < 0.05". Am Statistician. Pages 1-19  Mar 20,  2019. doi: 10.1080/ 00031305.2019.1583913

https://www.tandfonline.com/doi/full/10.1080/00031305.2019.1583913

Scientists rise up against statistical significance. Valentin Amrhein, Sander Greenland, Blake McShane and more than 800 signatories call for an end to hyped claims and the dismissal of possibly crucial effects. Nature. COMMENT. Mar 20, 2019.

https://www.nature.com/articles/d41586-019-00857-9  

# behav: backward walking, navigational uncertainties (among Cataglyphis velox)

<< Current opinion in insect navigation assumes that animals need to align with the goal direction to recognise familiar views and approach it. Yet, ants sometimes drag heavy food items backward to the nest and it is still unclear to what extent they rely on visual memories while doing so. >>

<< ants do indeed recognise and use the learnt visual scenery to guide their path while walking backward. In addition, the results show that backward homing ants estimate their directional certainty by combining visual familiarity with other cues such as their path integrator and the time spent backward. >>

Sebastian Schwarz, Leo Clement, et al.  How do backward walking ants (Cataglyphis velox) cope with navigational uncertainty? doi: 10.1101/2019.12.16.877704. Dec 17, 2019.

https://www.biorxiv.org/content/10.1101/2019.12.16.877704v1

# life: exponential post-Donald (without Donald), how AI could interfere (drive) next political elections.

<< Recent news that the Republican National Committee (RNC) has used an AI-generated video to criticize Joe Biden shows how likely AI is to transform our upcoming elections. >>️

<< Through templates that are easy and inexpensive to use, we are going to face a Wild West of campaign claims and counter-claims, with limited ability to distinguish fake from real material and uncertainty regarding how these appeals will affect the election. >>️

<< In the coming year, response times may drop to minutes, not hours or days. AI can scan the internet, think about strategy, and come up with a hard-hitting appeal. >>️

<< AI provides an inexpensive way to generate instant responses without having to rely on highly-paid consultants or expert videographers. >>️

<< AI enables very precise audience targeting, which is crucial in political campaigns. >>️

<< AI likely will democratize disinformation by bringing sophisticated tools to the average person interested in promoting their preferred candidates as well. People no longer must be coding experts or video wizards to generate text, images, video, or programs. They don’t necessarily have to work for a troll farm to create havoc with the opposition. They can simply use advanced technologies to spread the messages they want. In that sense, anyone can become a political content creator and seek to sway voters or the media. >>️

Darrell M. West. How AI will transform the 2024 elections. May 3, 2023.

https://www.brookings.edu/blog/techtank/2023/05/03/how-ai-will-transform-the-2024-elections/

Also: 'ai', 'analogy', 'Potus', 'RAG-time', 'CTZ', 'Donald' in https://www.inkgmr.net/kwrds.html

Keywords: life, ai, analogy, potus, RAG, CTZ, Donald

# behav: apropos of the uncertainty about the 'Zona Incerta', a thresholding mechanism involved in curiosity and novelty-seeking behavior

<< Motivational drives are internal states that can be different even in similar interactions with external stimuli. Curiosity as the motivational drive for novelty-seeking and investigating the surrounding environment is for survival as essential and intrinsic as hunger. Curiosity, hunger, and appetitive aggression drive three different goal-directed behaviors—novelty seeking, food eating, and hunting >>️

<< Optogenetic activation of inhibitory neurons in medial ZI (ZIm) [medial Zona Incerta in mouse, freedom to choose what it wants], ZImGAD2 neurons, showed a dramatic increase in positive arousal level, depth of investigation, and duration of interaction with conspecifics and novel objects compared with familiar objects, crickets, and food. Optogenetic or chemogenetic deactivation of these neurons decreased depth and duration of investigation. Moreover, [AA] found that ZImGAD2 neurons are more active during deep investigation as compared with during shallow investigation. >>

<< [They] found that activation of prelimbic cortex (PL) axons into ZIm increases arousal level, and chemogenetic deactivation of these axons decreases the duration and depth of investigation. >>

<< Optogenetic activation of ZImGAD2 axons into lateral periaqueductal gray (lPAG) increases the arousal level, whereas chemogenetic deactivation of these axons decreases duration and depth of investigation. Calcium fiber photometry of these axons showed high activity during deep investigation and no significant activity during shallow investigation, suggesting a thresholding mechanism. >>️

<< Last, [AA] found a new subpopulation of inhibitory neurons in ZIm expressing tachykinin 1 (TAC1) that monosynaptically receive PL inputs and project to lPAG. Optogenetic activation and deactivation of these neurons, respectively, increased and decreased depth and duration of investigation. >>️️

Ahmadlou, Janou H. W. Houba, et al. A cell type–specific cortico-subcortical brain circuit for investigatory and novelty-seeking behavior. Science . Vol. 372, Issue 6543, eabe9681. doi: 10.1126/ science.abe9681. May 14, 2021. 

https://science.sciencemag.org/content/372/6543/eabe9681   

Brain mechanism of curiosity unraveled. Netherlands Institute for Neuroscience - KNAW.  May 13, 2021. 

https://www.sciencedaily.com/releases/2021/05/210513142430.htm

# phys: a base-level fuzziness; black holes and strange metals go to extremes in some common way

<< black holes and strange metals go to extremes in some common way (..)  electrons inside a variety of ceramic crystals called "cuprates" seem to dissipate energy as quickly as possible, apparently bumping up against a fundamental quantum speed limit. >>

<<  ħ is the quantum unit of uncertainty:  an inescapable, base-level fuzziness in nature >>

Natalie Wolchover. Universal Quantum Phenomenon Found in Strange Metals.   Nov 19, 2018.

https://www.quantamagazine.org/universal-quantum-phenomenon-found-in-superconductors-20181119/

https://twitter.com/QuantaMagazine/status/1104730889500745731

A. Legros, S. Benhabib, et al. Universal T-linear resistivity and Planckian dissipation in overdoped cuprates. Nature Physics. volume 15, pages 142–147 (2019).

https://www.nature.com/articles/s41567-018-0334-2

# phys: apropos of transitions, even a tiny wobble may reshape theoretical views of the universe

<< The long-awaited first results from the Muon g-2 experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory show fundamental particles called muons behaving in a way that is not predicted by scientists’ best theory, the Standard Model of particle physics. >>️

<< Like electrons, muons act as if they have a tiny internal magnet. In a strong magnetic field, the direction of the muon’s magnet precesses, or wobbles, much like the axis of a spinning top or gyroscope. The strength of the internal magnet determines the rate that the muon precesses in an external magnetic field and is described by a number that physicists call the g-factor. This number can be calculated with ultra-high precision. >>

<< The first result from the Muon g-2 experiment at Fermilab confirms the result from the experiment performed at Brookhaven National Lab two decades ago. Together, the two results show strong evidence that muons diverge from the Standard Model prediction. >>

<< The accepted theoretical values for the muon are:

g-factor: 2.00233183620(86)

anomalous magnetic moment: 0.00116591810(43)

[uncertainty in parentheses]

The new experimental world-average results announced by the Muon g-2 collaboration today are:

g-factor: 2.00233184122(82)

anomalous magnetic moment: 0.00116592061(41)

The combined results from Fermilab and Brookhaven show a difference with theory at a significance of 4.2 sigma, a little shy of the 5 sigma (or standard deviations) that scientists require to claim a discovery but still compelling evidence of new physics. The chance that the results are a statistical fluctuation is about 1 in 40,000. >>️

We’re thrilled to announce that the first results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics! #gminus2

https://t.co/tUx4ojzIps https://t.co/t1ufui2Mwu   

17:01  Apr 7,  2021

https://twitter.com/Fermilab/status/1379811596755681286

Tracy Marc. First results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics. Apr 7, 2021.

https://news.fnal.gov/2021/04/first-results-from-fermilabs-muon-g-2-experiment-strengthen-evidence-of-new-physics

Also

Themis Bowcock, Mark Lancaster. How we found hints of new particles or forces of nature – and why it could change physics. Apr 8, 2021.

 

https://theconversation.com/how-we-found-hints-of-new-particles-or-forces-of-nature-and-why-it-could-change-physics-158564

B. Abi et al. (Muon g−2  Collaboration)

 Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm. Phys. Rev. Lett. 126, 141801. Apr 7, 2021.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.141801

A primer in particle physics:

Jonathan Carroll. Explainer: Standard Model of Particle Physics. Aug 25, 2011.

https://theconversation.com/explainer-standard-model-of-particle-physics-2539

a 'cartouche' of the Standard Model 

https://images.theconversation.com/files/2516/original/sml_small.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1055&fit=crop&dpr=3

# behav: ADHD may have been a feature of nomadic exploration among hunter-gatherer societies

<< All mobile organisms forage for resources, choosing how and when to search for new opportunities by comparing current returns with the average for the environment. In humans, nomadic lifestyles favouring exploration have been associated with genetic mutations implicated in attention deficit hyperactivity disorder (ADHD), inviting the hypothesis that this condition may impact foraging decisions in the general population. >>️

David L. Barack, Vera U. Ludwig, et al. 

Attention deficits linked with proclivity to explore while foraging. Proc Royal Society B.  doi: 10.1098/ rspb.2022.2584. Feb 21, 2024. 

https://doi.org/10.1098/rspb.2022.2584     

<< Is it a legacy of the hunter-gatherer world? >> Arjun Ramakrishnan

Chen Ly. ADHD may have evolved to help foragers know when to cut their losses. newscientist.com Feb 21,2024.

https://www.newscientist.com/article/2418114-adhd-may-have-evolved-to-help-foragers-know-when-to-cut-their-losses

Also: nomads, bushmen, behav, uncertainty, curiosity, in https://www.inkgmr.net/kwrds.html

Keywords: adhd, nomads, hunter-gatherers, behavior, behaviour

# behav: use of social information in flight (among ‘griffon’ vultures Gyps fulvus and G. rueppellii)

 <<Animals rely on a balance of personal and social information to decide when and where to move next in order to access a desired resource, such as food. The benefits from cueing on conspecifics to reduce uncertainty about resources availability can be rapidly overcome by the risks of within-group competition, often exacerbated toward low-ranked individuals. Being obligate soarers, relying on thermal updrafts to search for carcasses around which competition can be fierce, vultures represent ideal models to investigate the balance between personal and social information during foraging movements. Linking dominance hierarchy, social affinities and meteorological conditions to movement decisions of eight captive vultures, Gyps spp., released for free flights in natural-like soaring conditions,  (AA) found that they relied on social information (i.e. other vultures using/having used the thermals) to find the next thermal updraft, especially in unfavourable flight conditions. Low-ranked individuals were more likely to disregard social cues when deciding where to go next, possibly to minimise the competitive risk of social aggregation. These results exemplify the architecture of decision-making during flight in social birds. It suggests that the environmental context, the context of risk and the social system as a whole calibrate the balance between personal and social information use. >> 

Sassi Yohan, Nouzieres Basile, Scacco Martina, et al. The use of social information in vulture flight decisions. bioRxiv. doi: 10.1101/ 2023.07.26.550671. Jul 28, 2023.

https://www.biorxiv.org/content/10.1101/2023.07.26.550671v1

Also: behav, in https://www.inkgmr.net/kwrds.html