# gst: even tight-binding billiards could exhibit chaotic behaviors

<< Recent works have established universal entanglement properties and demonstrated validity of single-particle eigenstate thermalization in quantum-chaotic quadratic Hamiltonians. However, a common property of all quantum-chaotic quadratic Hamiltonians studied in this context so far is the presence of random terms that act as a source of disorder. >>

AA << introduce tight-binding billiards in two dimensions, which are described by non-interacting spinless fermions on a disorder-free square lattice subject to curved open boundaries. >>

They <<  show that many properties of tight-binding billiards match those of quantum-chaotic quadratic Hamiltonians (..) these properties indeed appear to be consistent with the emergence of quantum chaos in tight-binding billiards. This statement nevertheless needs to be taken with some care since there exist a sub-extensive (in lattice volume) set of single-particle eigenstates that are degenerate in the middle of the spectrum at zero energy (i.e., zero modes), for which the agreement with RMT (random matrix theory) predictions may not be established. >>

Iris Ulcakar, Lev Vidmar. Tight-binding billiards. arXiv:2206.07078v1 [cond-mat.stat-mech]. Jun 14, 2022. 

https://arxiv.org/abs/2206.07078

Also

keyword 'billiard' in FonT

https://flashontrack.blogspot.com/search?q=billiard

keyword 'chaos' | 'chaotic' in Font

https://flashontrack.blogspot.com/search?q=chaos

https://flashontrack.blogspot.com/search?q=chaotic

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

https://inkpi.blogspot.com/search?q=caos

https://inkpi.blogspot.com/search?q=caotico

keywords: gst, billiard, chaos, chaotic behavior

# gst: apropos of transitions, perspectives on viscoelastic flow instabilities; the 'porous individualism'

<< given the observation that disorder can suppress the transition to elastic turbulence in 2D porous media (..), it has been unclear whether and how this transition manifests in disordered 3D media — though elastic turbulence has been speculated to underlie the long-standing observation that the macroscopic flow resistance of an injected polymer solution can abruptly increase above a threshold flow rate in a porous medium, but not in bulk solution >>️

AA << found that the transition to unstable flow in each pore is continuous, arising due to the increased persistence of discrete bursts of instability above a critical value of the characteristic (Weissenberg no.) Wi; however, the onset value varies from pore to pore. This observation that single pores exposed to the same macroscopic flow rate become unstable in different ways provides a fascinating pore-scale analog of “molecular individualism” [P.  De Gennes, Molecular individualism. Science 276, 1999–2000 (1997)], in which single polymers exposed to the same extensional flow elongate in different ways; the authors therefore termed it “porous individualism”, although it is important to note that here, this effect is still at the continuum (not molecular) scale. Thus, unstable flow is spatially heterogeneous across the different pores of the medium, with unstable and laminar regions coexisting >>

AA << quantitatively established that the energy dissipated by unstable pore-scale fluctuations generates an anomalous increase in flow resistance through the entire medium that agrees well with macroscopic pressure drop measurements. >>

Sujit S. Datta, Arezoo M. Ardekani, et al. Perspectives on viscoelastic flow instabilities and elastic turbulence. arXiv: 2108.09841v1 [physics.flu-dyn]. Aug 22, 2021. 

https://arxiv.org/abs/2108.09841

Also

keyword 'transition' | 'transitional' in FonT

https://flashontrack.blogspot.com/search?q=transition

https://flashontrack.blogspot.com/search?q=transitional

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

https://inkpi.blogspot.com/search?q=transition

https://inkpi.blogspot.com/search?q=transizione

https://inkpi.blogspot.com/search?q=transizioni

keywords: gst, droplet, fluctuations, disorder, instability, viscoelastic flow instability, turbulence, elastic turbulence, individualism, porous individualism, transition

# gst: apropos of transitions, reversing order-disorder of Janus nano particles confined in two dimensions

<< Janus particles with different patch sizes, confined to two dimensions, generate a series of patterns of interest to the field of nanoscience >>

AA << observe reverse melting, where for some densities the system melts under cooling. For a broad range of hydrophobic patch sizes (..), a reentrant transition from solid to liquid and then to an ordered phase emerges as temperature (T) decreases due to the formation of rhombus chains at low T.  This reentrant phase has pseudo long-range orientational order but short-range translational order, >>

The << work provides guidelines to study the melting and assembly of Janus particles in two dimensions, as well as mechanisms to generate phases with specific symmetry. >>️️

️

Yihao Liang, Boran Ma, Monica Olvera de la Cruz. Reverse order-disorder transition of Janus particles confined in two dimensions. Phys. Rev. E 103, 062607. Jun 9, 2021.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.103.062607

Also

keyword 'nano' in FonT

https://flashontrack.blogspot.com/search?q=nano

keyword 'nano' in Notes 

(quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=nano

# gst: transitions in disordered medium.

AA << study computationally the dynamics of forced, Brownian particles through a disordered system. As the concentration of mobile particles and/or fixed obstacles increase, (AA) characterize the different regimes of flow and address how clogging develops. >>️

AA << show that clogging is preceded by a wide region of anomalous transport, characterized by a power law decay of intermittent bursts. (..) this abnormal flow region is characterized by a coexistence between mobile and arrested particles, and their relative populations change smoothly as clogging is approached. >>

️

Sergi G. Leyva, Ignacio Pagonabarraga. Clogging transition and anomalous transport in driven suspensions in a disordered medium. Phys. Rev. E 109, 014618. Jan 31, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.109.014618

img:  https://twitter.com/PhysRevE/status/1753068208586711072   

Also: transition, particle, disorder, in https://www.inkgmr.net/kwrds.html

Keywords: gst, transition, particle, disorder

# gst: ordered patterns found when mixing granular matter

AA << report remarkably persistent mixing and non-mixing regions in a three-dimensional dynamical system where randomness is expected. A spherical shell half-filled with dry non-cohesive particles and periodically rotated about two horizontal axes generates complex structures that vary non-trivially with the rotation angles. >>

Zafir Zaman, Mengqi Yu, et al.  Persistent structures in a three-dimensional dynamical system with flowing and non-flowing regions. Nature Comm vol 9, no 3122 (2018)  doi: 10.1038/s41467-018-05508-7

https://www.nature.com/articles/s41467-018-05508-7   

Emily Ayshford. When mixing granular matter, order among disorder. Northwestern University. Aug 14, 2018.

https://m.phys.org/news/2018-08-granular-disorder.html   

# gst: even a tiny noise could self-induce new chimera patterns through stochastic resonance

<< Noise induced order in excitable systems has diverse manifestations, such as coherence resonance (CR) and stochastic resonance. In this context a less explored phenomenon is self-induced stochastic resonance (SISR). Unlike CR, SISR may arise away from the bifurcation threshold and the properties of the induced oscillations depend upon both the noise intensity and the time-scale separation factor. In this work, (AA) report a new chimera pattern in a network of coupled excitable units, namely the self-induced stochastic resonance chimera or SISR-chimera that originates from the SISR phenomenon. (AA) explore the detailed dynamics of the SISR-chimera in the parameter space using proper quantitative measures. (AA) have found that unlike CR chimera, the SISR-chimera pattern strongly depends upon the ratio of time scale and noise intensity. Therefore, this type of chimera pattern can be induced even for a tiny noise intensity if the time scale separation of the activator and inhibitor is large enough. >>️

Taniya Khatun, Tanmoy Banerjee. Genesis of chimera patterns through self-induced stochastic resonance. arXiv:2305.06824v1 [nlin.AO]. May 11, 2023. 

https://arxiv.org/abs/2305.06824

Also:  chimera, noise, disorder in  https://www.inkgmr.net/kwrds.html  

Keywords: gst, noise, disorder, chimera, self-induced stochastic resonance chimera 

# gst: leading to an order-disorder transition to design of decentralized swarm systems.

<< Adaptive collective behavior underpinned by specialized optimization strategies is ubiquitous in the natural world. (AA) develop a minimal model of agents that explore their environment by means of sampling trajectories. (..) (They) find that, as cognitive agents build and update their internal, cognitive representation of the causal structure of their environment, complex patterns emerge in the system (..) Exchange of information among the agents leads to an order-disorder transition. As a result of the spontaneous breaking of translational symmetry, a Goldstone mode emerges, which points at a collective mechanism of information transfer >>

Hannes Hornischer, Stephan Herminghaus, Marco G. Mazza. Structural transition in the collective behavior of cognitive agents. Scientific Reports. volume 9, Article number: 12477 (2019).   https://www.nature.com/articles/s41598-019-48638-8 

Nature's most beautiful performances could inspire the next generation of artificial intelligence. Loughborough University. Sep 6, 2019.    https://m.techxplore.com/news/2019-09-nature-beautiful-artificial-intelligence.html  

# gst: emergence of chimeras driven by non-normality

<< The emergence of order in nature manifests in different phenomena, with synchronization being one of the most representative examples. >>️

<< Particular attention has been paid to the emergence of chimera states, where subsets of synchronized oscillations coexist with asynchronous ones. Such coexistence of coherence and incoherence is a perfect example where order and disorder can persist in a long-lasting regime. >>

<< Based on a symmetry-breaking mechanism, in this paper, (AA) shed light on the role that non-normality, a ubiquitous structural property of real networks, has in the emergence of several diverse dynamical phenomena, e.g., amplitude chimeras or oscillon patterns. >>️

<< Specifically, (they) demonstrate that the prevalence of source or leader nodes in networks leads to the manifestation of phase chimera states. >>️

Riccardo Muolo, Joseph D. O'Brien, et al. Persistence of chimera states and the challenge for synchronization in real-world networks. arXiv: 2306.00237v1 [nlin.PS]. May 31, 2023.

https://arxiv.org/abs/2306.00237

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

Keywords: gst, chimera, network, synchronization, swarm, noise, order, disorder, normal

# gst: apropos of transitions, randomness can stabilize edge states in short- lifetime regions of disordered periodically-driven systems

<< lifetimes of the edge states exhibit universal behavior when random potentials exist since the edge- and bulk- dominant eigenstates are mixed, leading to that lifetimes are prolonged by random potentials in the region II (short- lifetime region) and shortened in the region I (long- lifetime region). >>

<<  it is an intriguing phenomenon that random potentials tend to stabilize edge states in the region II (short- lifetime regions). >>

Ken Mochizuki, Kaoru Mizuta, Norio Kawakami. Fate of Topological Edge States in Disordered Periodically-driven Nonlinear Systems. arXiv: 2108.00649 (nlin). Aug 2, 2021.

https://arxiv.org/abs/2108.00649

Also

keyword 'random' in FonT

https://flashontrack.blogspot.com/search?q=random

keyword 'disorder' in FonT

https://flashontrack.blogspot.com/search?q=disorder

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

https://inkpi.blogspot.com/search?q=disordine

# gst: how two chaotic systems can synchronize

<< For the first time the researchers were able to measure the fine grain process that leads from disorder to synchrony, discovering a new kind of synchronization between chaotic systems. They call this new phenomenon Topological Synchronization. >>

<< Chaotic systems, although unpredictable, still have a subtle global organization called strange attractor (..) Every chaotic system attracts its own unique strange attractor. By Topological Synchronization we mean that two strange attractors have the same organization and structures. At the beginning of the synchronization process, small areas on one strange attractor have the same structure of the other attractor, meaning that they are already synced to the other attractor. At the end of the process, all the areas of one strange attractor will have the structure of the other and complete Topological Synchronization has been reached. >> Nir Lahav.

Scientists reveal for first time the exact process by which chaotic systems synchronize. Bar-Ilan University. Jan 7, 2019.

https://m.phys.org/news/2019-01-scientists-reveal-exact-chaotic-synchronize.html

Nir Lahav, Irene Sendina-Nadal, et al.
Synchronization of chaotic systems: A microscopic description. Phys. Rev. E 98, 052204. Nov 6, 2018. doi: 10.1103/PhysRevE.98.052204

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.98.052204

# gst: diffusivity of ordered and freely evolving bubbly suspensions.

AA << investigate the dispersion of a passive scalar such as the concentration of a chemical species, or temperature, in homogeneous bubbly suspensions, by determining an effective diffusivity tensor. Defining the longitudinal and transverse components of this tensor with respect to the direction of averaged bubble rise velocity in a zero mixture velocity frame of reference, (AA) focus on the convective contribution thereof, this being expected to be dominant in commonly encountered bubbly flows. >>

<< In the limits of low and of high Péclet number, including inertial effect of the flow does not affect the scaling of the effective diffusivity with respect to the Péclet number. These results are confirmed by direct numerical simulations performed in different flow regimes, for spherical or very deformed bubbles and from vanishingly small to moderate values of the Reynolds number. Scalar transport in arrays of freely rising bubbles is considered by us subsequently, using numerical simulations. In this case, the dispersion is found to be convectively enhanced at low Péclet number, like in ordered arrays. At high Péclet number, the Taylor dispersion scaling obtained for ordered configurations is replaced by the one characterizing a purely mechanical dispersion, like in random media, even if the level of disorder is very low. >>️

Aurore Loisy, Aurore Naso, Peter D. M. Spelt. The effective diffusivity of ordered and freely evolving bubbly suspensions. arXiv:2301.00028v1 [physics.flu-dyn]. Dec 30, 2022. 

https://arxiv.org/abs/2301.00028

Also

keyword "bubble" in FonT

https://flashontrack.blogspot.com/search?q=bubble

keyword "bolla" | "bolle" in Notes (quasistochastic-poetry): 

https://inkpi.blogspot.com/search?q=bolla

https://inkpi.blogspot.com/search?q=bolle

Keywords: gst, bubble, bubbly suspensions, diffusion, fluctuation

# s-epidem: diurnal mosquitoes with Zika virus inside

<< Experts are concerned that the illness, which is increasingly linked to a disorder that causes paralysis, may become a problem in the U.S. >>

Dina Fine Maron. Zika Disease: Another Reason to Hate Mosquitoes.  October 8, 2015

http://www.scientificamerican.com/article/zika-disease-another-reason-to-hate-mosquitoes/

A new global map highlights places #Zika could spread

https://twitter.com/ScienceNews/status/690677908927598593

Meghan Rosen. Rapid spread of Zika virus in the Americas raises alarm. Mosquito-borne disease linked to birth defect is pushing northward from Brazil. 3:08PM, January 22, 2016

https://www.sciencenews.org/article/rapid-spread-zika-virus-americas-raises-alarm

# gst: local elastic properties of strongly disordered matter

<< The local elastic properties of strongly disordered material are investigated using the theory of correlated random matrices. A significant increase in stiffness is shown in the interfacial region, the thickness of which depends on the strength of disorder. It is shown that this effect plays a crucial role in nanocomposites, in which interfacial regions are formed around each nanoparticle. >>️

D. A. Conyuh, A. A. Semenov, Y. M. Beltukov. Effective elastic moduli of composites with a strongly disordered host material. Phys. Rev. E 108, 045004. Oct 20, 2023. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.108.045004

Also: elastic, noise, particle, nano, in https://www.inkgmr.net/kwrds.html

Keywords: gst, elastic, noise, particle, nano

# pharma: a 'magical' (engineered) Escherichia coli to produce psychedelic psilocybin

<< Psilocybin, the prodrug of the psychoactive molecule psilocin, has demonstrated promising results in clinical trials for the treatment of addiction, depression, and post-traumatic stress disorder.  >>

AA << present the development of a modular biosynthetic production platform in the model microbe, Escherichia coli. (..) This is the highest psilocybin titer achieved to date from a recombinant organism and a significant step towards demonstrating the feasibility of industrial production of biologically-derived psilocybin. >>

Alexandra M.Adams, Nicholas A.Kaplan, et al. In vivo production of psilocybin in E. coli. Metabolic Engineering. Volume 56, pages 111-9. doi: 10.1016/j.ymben.2019.09.009. Sep 21, 2019.

https://www.sciencedirect.com/science/article/pii/S109671761930309X

Tanya Lewis. E. coli Could Produce a Popular Psychedelic for Therapeutic Use. Scientists engineered the bacterium to produce psilocybin. SCIAM. 322, 1, 16. Jan 2020.

https://www.scientificamerican.com/article/e-coli-could-produce-a-popular-psychedelic-for-therapeutic-use/

Also

keyword 'magic' in FonT

https://flashontrack.blogspot.com/search?q=magic

# gst: riddles of the sphinx tilings, when at low temperatures you could find a chiral order.

<< The sphinx tile, a hexiamond composed of six equilateral triangles in the shape of a sphinx, has interesting and complex tiling behavior due to its chirality and asymmetry. >>️

<< for larger frames (AA) introduce a Monte Carlo (MC) method to create randomized tilings. Key to the latter is the identification of fundamental shapes ("polyads") that have multiple tilings and allow a rejection-free MC move once the polyad is identified. >>

AA << also introduce an Ising-like chiral interaction energy between neighboring sphinx tiles and study how the system behaves as a function of temperature; at low temperatures, chiral ordering is found. >>️

Greg Huber, Craig Knecht, Walter Trump, Robert M. Ziff. Riddles of the sphinx tilings. arXiv: 2304.14388v2 [cond-mat.stat-mech]. May 1, 2023.

https://arxiv.org/abs/2304.14388

Also: 'chiral', 'disorder' in https://www.inkgmr.net/kwrds.html

Keywords: gst, sphinx, sphinx tiles, chirality, asymmetry

# 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

# gst: density fluctuations may exist in an amorphous matrix

<< Silicon does not have to be crystalline, but can also be produced as an amorphous thin film. In such amorphous films, the atomic structure is disordered like in a liquid or glass. If additional hydrogen is incorporated during the production of these thin layers, so-called a-Si:H layers are formed. >>

<< With this study, we show that the a-Si:H is by no means a homogeneously amorphous material. The amorphous matrix is interspersed with nanometre-sized areas of varying local density, from cavities to areas of extremely high order, >> Klaus Lips

<< We find a nanoscopic order in the disorder of the a-Si:H layers by X-ray scattering measurements (..) We were then able to determine the distribution of the hydrogen atoms in the amorphous network by neutron scattering (..) We were able to discover nanometer-sized voids, which are created by slightly more than 10 missing atoms. These voids arrange themselves into clusters with a recurrent distance of about 1.6 nanometres to each other, >> Eike Gericke

Density fluctuations in amorphous silicon discovered. Helmholtz Association of German Research Centres. Oct 29, 2020. 

https://phys.org/news/2020-10-density-fluctuations-amorphous-silicon.html

Eike Gericke, Jimmy Melskens, et al. Quantification of Nanoscale Density Fluctuations in Hydrogenated Amorphous Silicon. Phys. Rev. Lett. 125, 185501. Oct 29,  2020. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.185501

# s-behav: two (multi?) step sleeper

A. Roger  Ekirch. Segmented  Sleep  in  Preindustrial  Societies. Sleep. Volume 39,  Issue  03. Letters To The Editor. http://dx.doi.org/10.5665/sleep.5558

http://journalsleep.org/ViewAbstract.aspx?pid=30498.

Bora Zivkovic. What is a `natural' sleep pattern? December 5, 2011

http://blogs.scientificamerican.com/a-blog-around-the-clock/what-is-a-natural-sleep-pattern/    

http://blogs.scientificamerican.com/a-blog-around-the-clock/2011/08/29/everything-you-always-wanted-to-know-about-sleep-but-were-too-afraid-to-ask/

Richard A. Friedman. Sleep  Disorder?  Wake  Up  and  Smell  the  Savanna. March  14,  2006

http://www.nytimes.com/2006/03/14/health/14beha.html

http://circadiana.blogspot.com/2006/03/what-is-natural-sleep-pattern.html

# gst: transitions by coupled instabilities

AA << present an experimental study of quasiperiodic transitions between a highly ordered square-lattice pattern and a disordered, defect-riddled state, in a circular Faraday system. (They)  show that the transition is driven initially by a long-wave amplitude modulation instability, which excites the oscillatory transition phase instability, leading to the formation of dislocations in the Faraday lattice. The appearance of dislocations dampens amplitude modulations, which prevents further defects from being created and allows the system to relax back to its ordered state. The process then repeats itself in a quasiperiodic manner. >>

Valeri Frumkin, Shreyas Gokhale. Coupled instabilities drive quasiperiodic order-disorder transitions in Faraday waves. Phys. Rev. E 108, L012601. July 17, 2023. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.108.L012601

Also: parrondo, tit-for-tat, game, transition, chaos, in https://www.inkgmr.net/kwrds.html

Keywords: parrondo, tit-for-tat, game,  transition, chaos