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lunedì 11 ottobre 2021

# gst: intermittent large-intensity pulses (LIE) due to instabilities in quasiperiodic motion (in Zeeman laser)

AA << report intermittent large-intensity pulses that originate in Zeeman laser due to instabilities in quasiperiodic motion, >>

<< one route follows torus-doubling to chaos and another goes via quasiperiodic intermittency in response to variation in system parameters. >>

<< During quasiperiodic intermittency, the temporal evolution of the laser shows intermittent chaotic bursting episodes intermediate to the quasiperiodic motion instead of periodic motion >>

<< The intermittent bursting appears as occasional large-intensity events (LIE). In particular, this quasiperiodic intermittency has not been given much attention so far from the dynamical system perspective, in general. >>

S. Leo Kingston, Arindam Mishra, Marek Balcerzak, Tomasz Kapitaniak, Syamal K. Dana. Instabilities in quasiperiodic motion lead to intermittent large-intensity events in Zeeman laser. arXiv: 2109.11847v1 [nlin.CD]. Sep 24, 2021. 


keywords: gst, quasiperiodic motion, intermittency, quasiperiodic intermittency, instability, chaos.


giovedì 7 ottobre 2021

# gst: depicting scenarios between wobblers and kinks; energy transfers and destructive interferences

<< asymmetric scattering between wobblers and kinks (..) is investigated in two different scenarios. First, the collision between wobblers with opposite phase is analyzed. (..) a destructive interference between the shape modes of the colliding wobblers takes place at the impact time. The second scenario involves the scattering between a wobbler and an (unexcited) kink. In this case the energy transfer from the wobbler to the kink can be examined. The dependence of the final velocities and wobbling amplitudes of the scattered wobblers on the collision velocity and on the initial wobbling amplitude is discussed. Both situations lead to very different fractal structures in the velocity diagrams. >>️

<< it is also worthwhile mentioning the results displayed (..) It can be verified that systematically when a scattered wobbler gains more kinetic energy than the other, it obtains less vibrational energy and vice versa. >>️

A. Alonso-Izquierdo, L. M. Nieto, J. Queiroga-Nunes. Asymmetric scattering between kinks and wobblers. arXiv:2109.13904 (hep-th). Sep 28, 2021. 




mercoledì 6 ottobre 2021

# gst: apropos of disorder & fluctuations

a 'synthetic disorder & fluctuations' from these two blogs ... 

keyword 'disorder' in FonT 

keyword 'disordine' in Notes (quasi-stochastic poetry) 

keyword 'error' | 'fuzzy' | 'noise'  in FonT



keywords 'errore' | 'errori' in Notes (quasi-stochastic poetry)


keyword 'caos' | 'caotico' in Notes  (quasi-stochastic poetry) 


keyword 'waves' in FonT 

keyword 'onda' in Notes 
(quasi-stochastic poetry) 

keyword 'gst' (General Sistem Theory) in FonT 





venerdì 1 ottobre 2021

# ai: perpetual nirvana among 'self-addicted', 'self-cracked', 'playful' machines, the wireheading effect.

<< In 1953, a Harvard psychologist thought he discovered pleasure – accidentally – within the cranium of a rat. With an electrode inserted into a specific area of its brain, the rat was allowed to pulse the implant by pulling a lever. It kept returning for more: insatiably, incessantly, lever-pulling. In fact, the rat didn’t seem to want to do anything else. Seemingly, the reward centre of the brain had been located. >>️

<< More than 60 years later, in 2016, a pair of artificial intelligence (AI) researchers were training an AI to play video games. The goal of one game – Coastrunner – was to complete a racetrack. But the AI player was rewarded for picking up collectable items along the track. When the program was run, they witnessed something strange. The AI found a way to skid in an unending circle, picking up an unlimited cycle of collectables. It did this, incessantly, instead of completing the course. >>️

<< What links these seemingly unconnected events is something strangely akin to addiction in humans. Some AI researchers call the phenomenon "wireheading". >>️

Thomas Moynihan, Anders Sandberg. Drugs, robots and the pursuit of pleasure – why experts are worried about AIs becoming addicts. The Conversation. Sep 14, 2021. 


Rock'n Roll Monkey/Unsplash, FAL (img)  


FonT: so one could hypothesize a suitable 'magic string' that mitigates hypothetical autocatalytic pulsatile wireheading effects, even for artificial, bio-artificial entities.

An ethno-drug revisited ... Ayahuasca, prelude of a "magic string" in neuropharmacology. FonT.  July 8, 2018.


Also

"senza finalita' ideologiche, solo per curiosita',  giusto per giocare ..." in: 
Anomalous formation of molecules after vapor deposition. FonT.  Dec 31, 2015. 


A mechanism of analogy could be the master key to achieving an abstract artificial intelligence. FonT. Aug 10, 2021. 


keyword 'ia' | 'ai' in Notes (quasi- stochastic poetry)





keywords: ai, bots, artificial intelligence, wireheading effect, addiction


sabato 25 settembre 2021

# gst: ️apropos of spontaneous active matter, the active droploids.

<< Active matter comprises self-driven units, such as bacteria and synthetic microswimmers, that can spontaneously form complex patterns and assemble into functional microdevices. These processes are possible thanks to the out-of-equilibrium nature of active-matter systems, fueled by a one-way free-energy flow from the environment into the system. Here, (AA) take the next step in the evolution of active matter by realizing a two-way coupling between active particles and their environment, where active particles act back on the environment giving rise to the formation of superstructures. >>️

<< These structures hinge on mutually coupled structure formation processes of the colloids, which form an engine, and the surrounding solvent, which phase separates in regions of high colloidal density and encapsulates the engine within a droplet shell.  >>
Jens Grauer, Falko Schmidt, et al. Active droploids. arXiv:2109.10677v1 [cond-mat.soft]. Sep 22, 2021.


Also

keyword 'drop' | 'droplet' in FonT



keyword 'goccia' in Notes (quasi-stochastic poetry): 


keywords: gst, drops, droplets, colloids, active matter, active droploids, self-assembly, solitons.






mercoledì 22 settembre 2021

# gst: stagnation points controlling the onset and strength of chaotic fluctuations (in viscoelastic porous media flows)

<< Viscoelastic porous media flows become chaotic beyond critical flow conditions, impacting processes including enhanced oil recovery and targeted drug delivery. Understanding how geometric details of the porous medium affect the onset and strength of the chaotic flows can lead to fundamental insights and potential optimization of such processes. Recently, it has been argued that geometric disorder in the medium suppresses chaotic fluctuations. In contrast, (AA) demonstrate that disorder can also significantly enhance fluctuations given a different originally ordered configuration. (AA) show that the occurrence of stagnation points in the flow field is the vital factor controlling the onset and strength of fluctuation, providing a general and intuitive understanding of how pore geometry affects this important class of complex viscoelastic flows. >>

Simon J. Haward, Cameron C. Hopkins, Amy Q. Shen. Stagnation points control chaotic fluctuations in viscoelastic porous media flow. PNAS. 118 (38)  e2111651118. doi: 10.1073/ pnas.2111651118. Sep 21, 2021. 



Also

keyword 'elastic' | 'turbulence' | 'disorder' in FonT




keyword 'elastico' | 'turbolento' | 'disordine' in Notes
(quasi-stochastic poetry)





keywords: viscoelastic flows, porous media, stagnation, elastic turbulence, chaos, chaotic fluctuations, geometric disorder.


domenica 19 settembre 2021

# gst: approaching the complex mechanics of crumpled sheets

<< Crumpling an ordinary thin sheet transforms it into a structure with unusual mechanical behaviors, such as logarithmic relaxation, emission of crackling noise, and memory retention. >>️

<< the response of crumpled sheets to cyclic strain is intermittent, hysteretic, and encodes a memory of the largest applied compression. (..) these behaviours emerge due to an interplay between localized and interacting geometric instabilities in the sheet. >>

<< after training multiple memories can be encoded, a phenomenon known as return point memory. >>

AA << study lays the foundation for understanding the complex mechanics of crumpled sheets, and presents an experimental and theoretical framework for the study of memory formation in systems of interacting instabilities. >>️️

Dor Shohat, Daniel Hexner, Yoav Lahini. Memory from coupled instabilities in crumpled sheets. arXiv: 2109.05212v1 [cond-mat.soft]. Sep 11, 2021.


keywords: gst, sheet, crumpled sheets, instability, bistability, memory, return point memory