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martedì 5 aprile 2022

# gst: the solitary route to chimera states.

AA << show how solitary states in a system of globally coupled FitzHugh-Nagumo oscillators can lead to the emergence of chimera states. By a numerical bifurcation analysis of a suitable reduced system in the thermodynamic limit (they) demonstrate how solitary states, after emerging from the synchronous state, become chaotic in a period-doubling cascade. Subsequently, states with a single chaotic oscillator give rise to states with an increasing number of incoherent chaotic oscillators. In large systems, these chimera states show extensive chaos. (AA) demonstrate the coexistence of many of such chaotic attractors with different Lyapunov dimensions, due to different numbers of incoherent oscillators. >>

<<  While it is well known that self-organized wave patterns typically coexist within an interval of possible different wave numbers (..)(AA) show here the coexistence of coherence-incoherence patterns with different numbers of incoherent oscillators, which are in fact coexisting chaotic attractors with different Lyapunov dimensions. The incoherent oscillators in these coexisting attractors show extensive chaos of different dimensions. The total share of incoherent oscillators in a chimera state is a macroscopic quantity. Hence, within the range of such shares, where stable chimera states exist, (AA) find, for large systems, an increasing number of coexisting attractors with their numbers of incoherent oscillators increasing as well. (They) showed that, varying the coupling parameter, this extensive scenario is linked to the thermodynamic limit of the solitary regime, where the range of admissible numbers of incoherent oscillators shrinks down to one single oscillator in an infinitely large system. For this case, the emergence of the chaotic motion of the single incoherent oscillator could be shown in a period doubling cascade. >>

Leonhard Schulen, Alexander Gerdes, et al. The solitary route to chimera states. arXiv:2204.00385v1 [nlin.CD]. Apr 1, 2022.


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keyword 'FitzHugh-Nagumo oscillators' in APS | PubMed



keyword 'chaos' | 'chaotic' in Font



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



keywords: gst, solitons, solitary states, period-doubling cascade, chaos, Lyapunov dimension, FitzHugh-Nagumo oscillator, chimera state, dynamical systems.







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venerdì 1 aprile 2022

# life: Chimps distribute their time to groom other individuals in the same manner as humans structure their relationships.

AA << show that the time chimpanzees devote to grooming other individuals is well described by the same model used for human relationships, supporting the existence of similar social signatures for both humans and chimpanzees. Furthermore, the relationship structure depends on group size as predicted by the model, the proportion of high intensity connections being larger for smaller groups. >>

Diego Escribano, Victoria Doldan-Martelli, et al. Chimpanzees organize their social relationships like humans. bioRxiv. doi: 10.1101/ 2022.03.16.484664. March 17, 2022. 


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keywords 'chimp' | 'chimps' in FonT



keyword 'chimps' | 'sileno' in Notes (quasi-stochastic poetry)



keywords 'behav' in FonT


keywords: life, chimps, behav, behavior, behaviour, social relationships





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giovedì 31 marzo 2022

# gst: apropos of transitions, the vortex dynamics from a twisted baker map

<< A natural approach to understanding complicated systems is to analyze a col­lection of simple examples that retain some essential features of the complexity of the original systems. The baker map (..) is one of the simplest models of chaotic dynamical systems. It divides the unit square into p ≥ 2 equal vertical strips, and maps each strip to a horizontal one by squeezing it vertically by the factor p and stretching it horizontally by the same factor. The horizontal strips are laid out covering the square. Due to the squeezing/stretching, small initial errors get amplified under iteration, and results in an unpredictable long-term behavior. The name “baker” is used since the action of the map is reminiscent of the kneading dough (..). In this paper (AA) introduce a piecewise linear model of an interaction of stretching and twisting that produces vortex dynamics. >>

They << show that the set of hyperbolic repelling periodic points with complex conjugate eigenvalues and that without complex conjugate eigenvalues are simultaneously dense in the phase space >>

Yoshitaka Saiki, Hiroki Takahasi, James A. Yorke. The twisted baker map. arXiv: 2202.04304v2 [math.DS]. Feb 9, 2022. 


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keyword 'transition' | 'transitional' in FonT



keyword 'transition' | 'transizion*' in Notes (quasi-stochastic poetry)




keyword 'vortex' in FonT


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


keywords: gst, transition, vortex, baker map









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mercoledì 30 marzo 2022

# gst: solitary wave billiards

<<  In the present work (AA) introduce the concept of solitary wave billiards. I.e., instead of a point particle, (they) consider a solitary wave in an enclosed region and explore its collision with the boundaries and the resulting trajectories in cases which for particle billiards are known to be integrable and for cases that are known to be chaotic. A principal conclusion is that solitary wave billiards are generically found to be chaotic even in cases where the classical particle billiards are integrable. However, the degree of resulting chaoticity depends on the particle speed and on the properties of the potential. >>

J. Cuevas-Maraver, P.G. Kevrekidis, H. Zhang. Solitary wave billiards. arXiv: 2203.09489v1 [nlin.PS]. Mar 17, 2022. 


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keyword 'chaos' | 'chaotic' in Font



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



keyword | 'soliton' in FonT


keywords: gst, waves, solitons, billiard, chaos 





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sabato 26 marzo 2022

# gst life: apropos of critical points, love (at first sight and love from liking or friendship) might be a second-order phase transition.

<< The hypothesis of the human brain operation in vicinity of a critical point has been a matter of a hot debate in the recent years. >>

<< In this work, (AA) suggest that love might be an example of a second-order phase transition occurring in the brain. (They) show that this hypothesis explains a lot of well-known properties of love. Analyzing several most famous literature examples and a private diary, (they) show that the intensity of feelings exhibits a universal scaling behavior, distinguishing two cases: love at first sight and love developing from liking or friendship (friends first), both being studied in psychology. >>

The theory of second-order phase transitions developed by L.D. Landau (1980) << has inspired a lot of activity in physics, because it turned out that such transitions are characterized by a universal scaling behavior. Independently of the nature of the system, their parameters exhibit power law dependencies on the dimensionless parameter (temperature). >>

<< The key hypothesis of the present work is that love is a second-order phase transition occurring in the human brain under the influence of hormones, such as dopamine and serotonin (..). The brain switches from the normal operation in the critical regime to the supercritical regime because of the increase of the excitation (more dopamine) and reduction of the inhibition (less serotonin) (..). The order parameter of the transition is the intensity of feelings: before the transition, the subject has no particular feelings, while after the transition the feelings are non-zero. The most direct consequence is that the order parameter should exhibit a universal power law behavior: the feelings should grow as a square root of time α ∼√ >>

<< Since it is impossible to analyze the human feelings directly during such uncontrollable phenomenon as ”love at first sight”, (AA) have decided to perform a quantitative study of the intensity of feelings depicted in the literature. (..) (They) have chosen three well-known books for this analysis: ”Romeo and Juliet” (W. Shakespeare), ”The Lily of the Valley” (H. de Balzac, (..)), and ”Martin Eden” (J. London). >>

<< the case of a non-zero external ”bias”, which is a situation that occurs more often than love at first sight. Indeed, one usually knows several persons better than all the others, and thus some positive feelings towards some of them can be present before the transition occurs. (..) To study this transition quantitatively, (AA) have chosen another well-known book, ”Jane Eyre” by Charlotte Bronte. This books is also quite autobiographic, and famous for the psychological details, that got its author the title of ”first historian of the private consciousness”. The delay between the initial acquaintance and love is now of several weeks (about 45 days).

Dmitry Solnyshkov, Guillaume Malpuech. Love might be a second-order phase transition. arXiv: 2203.13246v1 [cond-mat.stat-mech]. Mar 24, 2022. 


Also

keyword 'transition' in FonT: 


keyword 'transizione' | 'transition' in Notes (quasi-stochastic poetry): 



keywords: gst, life, love, transitions,  critical point, phasetransition, second-order phase transition, brain, mind, behavior.







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giovedì 17 marzo 2022

# gst: apropos of weird transitions: from non-equilibrium conditions square droplets and liquid lattices can emerge.


<< Spontaneous emergence of organized states in materials driven by non-equilibrium conditions is of notable fundamental and technological interest. In many cases, the states are complex, and their emergence is challenging to predict. Here, (AA) show that an unexpectedly diverse collection of dissipative organized states emerges in a simple system of two liquids under planar confinement when driven by electrohydrodynamic shearing.

At low shearing, a symmetry breaking at the liquid-liquid interface leads to a one-dimensional corrugation pattern. 

At slightly stronger shearing, topological changes give raise to the emergence of Quincke rolling filaments, filament networks, and two-dimensional bicontinuous fluidic lattices. 

At strong shearing, the system transitions into dissipating polygonal, toroidal, and active droplets that form dilute gas-like states at low densities and complex active emulsions at higher densities. >>

Geet Raju, Nikos Kyriakopoulos, Jaakko V. I. Timonen. Diversity of non-equilibrium patterns and emergence of activity in confined electrohydrodynamically driven liquids. Science  Advances. Vol 7, Issue 38. doi: 10.1126/ sciadv.abh1642. 15 Sep 15, 2021.


<< Things in equilibrium tend to be quite boring, (..) It's fascinating to drive systems out of equilibrium and see if the non-equilibrium structures can be controlled or be useful. Biological life itself is a good example of truly complex behavior in a bunch of molecules that are out of thermodynamic equilibrium. >>  Jaakko Timonen.

Physicists make square droplets and liquid lattices. Aalto University. Sep 15, 2021. 


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keyword 'drop' | 'droplet' in FonT



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


keywords: gst, drop, droplet, lattice, transition, out of equilibrium.



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mercoledì 2 marzo 2022

# life; a hypothetical externalization of knowledge effects; humans are thought to have decreased in brain volume since the end of the last ice age (3,000 y.ago)


<< Human brain size nearly quadrupled in the six million years since Homo last shared a common ancestor with chimpanzees, but human brains are thought to have decreased in volume since the end of the last Ice Age. The timing and reason for this decrease is enigmatic. Here (AA) use change-point analysis to estimate the timing of changes in the rate of hominin brain evolution. (They) find that hominin brains experienced positive rate changes at 2.1 and 1.5 million years ago, coincident with the early evolution of Homo and technological innovations evident in the archeological record. But (AA) also find that human brain size reduction was surprisingly recent, occurring in the last 3,000 years. >>

Jeremy M. DeSilva, James F. A. Traniello, et al. When and Why Did Human Brains Decrease in Size? A New Change-Point Analysis and Insights From Brain Evolution in Ants. Front. Ecol. Evol.,  doi: 10.3389/ fevo.2021.742639. Oct 22, 2021. 


When and why did human brains decrease in size 3,000 years ago? Ants may hold clues. Frontiers. Oct 22, 2021.


Also

keyword 'nomade' | 'nomad' | 'nomads' | 'nomadic' | 'hunter-gatherers' in FonT






keyword 'nomade' | 'nomadi' in Notes (quasi-stochastic poetry)




keywords: evolution, brain, brain size, nomads, post-nomads, sociocultural effects



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